NDT HANDBOOK

Non-Destructive Testing
Inspector's
'v
Handbook
Visual Inspection (VT)
Liquid Penetrant Inspection (PT)
Magnetic Particle Testing (MT)
Ultrasonic Testing (UT)
Eddy Current Testing (ET)
RadiographicInspection (RT)

Preface
This referencebook was designed for use in the field and to support onthe-jobtraining. It should not be
Lised as a standardor referred to as a stand-alone document. This book covers basic formulas,charts, and other
NDT related information.
Dedication
To allthe people who have influencedmy naval career and where I am today in the NonDestructive field.
Thank you. I originally startedthis project as a self-knowledgeapplication and began receiving commentsfrom my
fellow colleagues requesting a copy. I soon realized that this would prove to be an invaluabletool for general
infomation in our field. I have received support from both military and civilian personnel and have taken a sample
of their suggestionsand compiled them for you, the end user. I wanted to take personal credit for this project and
realized it would not benefit the NDT field as a whole. Instead, I encourage you, the end user, to change,
manipulate, or configurethis book for yourself. In closing, "Share the Wealth with Others."
Last Revision Date
20 April 2002
Contact Information
Keoke526@hotmail.com
ndthandbook.zapto.org
Disclaimer
Thisbook is not intended for sale or any monetary benefit to the editor.
Inspector's Handbook

Table of Contents
Scope of Standards..............................................................................................................................................iv. .
.................................................................Chapter 1- General Information I d
..............................................................................................................ScheduleDesignationsof Pipe Sizes
.Copper Tubing Wall Thickness.....................................................................................................................1 1
...........................................................................................................................................Decimal to Inches 1 1
.............................................................................................................................TemperatureConversions -1 1
Fraction to Decimal Equivalent..................................................................................................................1-2
Decimal to Second Conversion.....................................................................................................................1-2
......................................................................................................................Numerical Place Value Chart 1 - 2
Elements of a Nondestructive Examination Symbol....................................................................................1-3
Elements of a Welding SyrnboL....................................................................................................................1-3
....................................................................................................................................Examples of Grooves 1-4
..................................................................................................................................Basic Joints (Welding) 1-4
.................................................................................................Order ofPerformingArithmetic Operations 1-5
....................................................................................................................................Ratio And Proportion 1-6
....................................................................................................................................Calculationof Area 1 - 7
Weld Area Calculation..................................................................................................................................1-7
.......................................................................................................................Common Symbolsand Terms 1-7
...............................................................................................................Solutionof Right-angled Triangles 1-9
................................................................................................................... .Basic Illustration of a Weld 1 10
.......................................................................................................................................WeldingProcesses - 11
.................................................................................................. .Backing Ring Common Defect Locations 1 12
.......................................................................................... .Consumable Insert Common Defect Locations 1 12
............................................................................................................Primary ProcessingDiscontinuities 4
Finish Processing Discontinuities................................................................................................................
..............................................................................................................................Dial Indicating Calipers 1-15
...............................................................................................................................................Micrometer 1 -15
.................................................................................................................Thread Terminology (fasteners) 1 -16
.............................................................................................................................Tap and Drill Size Chart: 1-16
.................................................................................................................Julian Date Calendar (Perpetual) 1-17
..............................................................................................................JulianDate Calendarp a p Year) -1-18
Chapter 2 .Visual Inspection......................................................................2-1
...........................................................................................................Common Definitionsand Examples 2 - 1
Chapter 3 .Liquid Penetrant Testing..........................................................3-1
Common Terms and Definitions..................................................................................................................-3-1
Prorated Maximum Number of Indications ..................................................................................................3-6
Areas of Circles.............................................................................................................................................3-6
Penetrant Wetting Characteristics.................................................................................................................3-7
Chapter 4 .Magnetic Particle Testing.........................................................4-1
.............................................................................................................CommonDefinitionsand Examples 4. 1
..................................................................................................LongitudinalMagnetizationMath Formula 4F7
..................................................................................................Prorated MaximumNumber of Indications -.............................................................................................................................................Areas of Circles 4
CommonTypes of Magnetization................................................................................................................4-9
Inspector's H m m k

..........................................................................................................................Theory: "RigheHand Rule -4-9
........................................................................................................................................Hysteresis=Curve -4-10
..............................................................................................Magnetic ParticleField Indicator(Pie Gage) 4- 11
. ....................................................................* & Chapter 5 Ultrasonic Testing 5-1
...................................................................................................................Common Terms and Definitions 5-1
............................................................................................................................CommonMath Formulas 5-12
.............................................................................................................Calibration Chart.UT Shearwave 5- 13
FPADSCRhD..............................................................................................................................................5-14
.............................................................................................................................................Velocity Chart 5-15
Chapter 6 .Eddy Current Testing ...............................................................6-1
...................................................................................................................Common Terms and Definitions - 1
Two Types of Electrical Current ...................................................................................................................6-6
Conductivity and the IACS...........................................................................................................................6-7
Right Hand Rule............................................................................................................................................6-7
Magnetic Domains ........................................................................................................................................6-9
Depth of Penetration................................................................................................................................... 6-12
Limitations of Eddy Current Testing .........................................................................................................6-18
Advantagesof Eddy Current Testing...................................................................................................... 6 18
Summaryof Properties of Eddy Currents ...................................................................................................6-18
Eddy Current Relationshipof Properties ............................................................................................6 - 18
...........................................................Chapter 7 .Radiographic Inspection 7-1
Common Definitions and Examples ............................................................................................................-7-1
..........................................................................................................Structureof the Atom and an Element 7-8
.............................................................................................................................Componentsof an Isotope 7-8
Characteristics of A Radioactive Element .................................................................................................... 7-8
Two Types of Radiation................................................................................................................................7-8
History of Radiography.................................................................................................................................7-9
60' Coverage for Pipes and Location Marker Measurements....................................................................7-11
Common Math Formulas ....................................................................................................................... 7 12
Magic Circles .......................................................................................................................................7 1 5
SingleWall Exposure I Single Wall Viewing for Plate ...........................................................................7-15
SingleWall Exposure1SingleWall Viewing for Pipe.............................................................................7-16
Double Wall Exposure 1Double Wall View (superimposed)...................................................................7-16
Double Wall ExposureI Double Wall View (offset) .............................................................................7-17
Double Wall Exposure 1SingleWall View ...............................................................................................7-17
KILLER CARL...........................................................................................................................................7-18
Penetrameter Material and GroupNumbers..............................................................................................7-18
Penny T-Hole Maximum Density.....................................................................................................7 19
2% PenetrameterQuality ConversionChart (X-RAY ONLY)...................................................................7-20
Basic Componentsof an X-ray Tube..........................................................................................................7-25
Types of ScatterRadiation.......................................................................................................................... 7-25
. .Radiographc Fllm Interpretation................................................................................................................7-25
. . ................................................................................................................Radiographic Film Interpretation 7-26
...................................................Probable Causes and CorrectiveAction for Automatic Film Processing 7-50
................................................Probable Causes and CorrectiveAction for Processed RadiographicFilm 7-51
Inspector's Handbook iii

Scope of Standards ..
NSTP 271 REQUIREMENTSFOR NONDESTRUCTIVETESTINGMETHODS - -
This document covers the requirements for conducting nondestructivetests (NDT) used in detenninin(
presence of surface and internal discontinuities in metals. It also containsthe -mum requirements necessary .qualifLnondestructivetest and inspection personnel, procedures, and nondestructiveequipment. This document
does not contain acceptancecriteria for nondestructivetest. This document does not cover all of the requirements
for performing nondestructivetests in an underwater environment.Nondestructivetests in an underwater
environment shallbe performed as specified in NAVSEA S0600-AA-PRO-070.
NSTP 248 REQUIREMENTS FOR WELDING AND BRAZING PROCEDURE AND PERFORMANCE
QUALIFICATION
This document contains the requirements for the qualificationof welding and brazing procedures, welders,
welding operators,brazers and brazing operators that must be met prior to any production fabrication. It includes
manual, semiautomatic,automatic and machine welding and brazing of ferrous, nonferrous, and dissimilarmetals.
The qualificationtests required by this document are devisedto demonstratethe adequacy of the welding or
brazing procedures and to demonstratethe abilityof welders, brazers, welding operatorsand brazing operatorsto
produce soundwelds orbrazes.
NSTP 278 REQUIREMENTSFOR FABRICATIONWELDING AND INSPECTION,AND CASTING
INSPECTIONAND REPAIR FOR MACHINERY,PIPING, AND PRESSUREVESSELS
Thisdocumentcontainsthe welding and alliedprocesses (exceptbrazing) and casting requirements
including inspection for the fabrication,alteration, or repair of any item or component of machinery, piping, and
pressure vessels in ships of the United StatesNavy.
MILSTD 2035 NONDESTRUCTIVE TESTING ACCEPTANCE CRITERIA
The acceptance criteriacontainedherein are for use in determining the acceptability of nondestructive t. -(NDT)discontinuitiesin castings,welds, forgings, extrusions, cladding, and other productswhen specifiedby the
applicableNaval Sea Systems Command (NAVSEA)drawing, specification, contract, order, or directive.
NSTP 1688FABRICATION,WELDING AND INSPECTION SUBMARINEAPPLICATIONS
This document containsminimum requirements for fabrication and inspectionof submarineand non
combatant submersiblestructures, including shipbuildingpractices, specificationsfor materials, weldjoint design,
workmanship,welding, inspection, and record requirements.
MILSTD 1689FABRICATION,WELDING, AND INSPECTION OF SHIPSSTRUCTURE
This standard contains the minimum requiremeas for the fabrication and inspection of the hull and
associated structures of combatant surface ships. The requirements for shipbuilding,materials, welding, welding
design, mechanicalfasteners, workmanship, inspection, forming, castings and records are included. It also applies
to those submarine structureswhich are not high-yield strengthsteels.
MILSTD 22DWELDED JOINT DESIGN
This standard covers welded joint designs for manual, semi-automatic, and automatic arc and gaswelding
processes for use onmetalsand weldments, as applicable, when invoked by a fabricationdocument. The welded
joint designs shownherein represent standardjoint designsused in welded fabrication and are not intendedto be
all inclusive.

NSTP CHAPTER 074-VOLUME 1WELDING AND ALLIED PROCESSES
This chapter furnishesboth the minimum mandatory requirements (indicatedby the word shall) and
guidance information (indicatedby the words should or may) necessary for welding, brazing, inspection, and
safetywhen used for ship maintenance, repair, and alteration.
-NSTP CHAPTER074-VOLUME 2 NONDESTRUCTIVE TESTING OF METALS QUALIFICATION
AND CERTIFICATION REQUIREMENTS FOR NAVAL PERSONNEL (NON-NUCLEAR)
This chapter is M s h e d to ensure achievementof uniform and reliable nondestructivetests on naval
materialsand components,implementationof the training, qualification, and certificationprograms described in
this chapter shouldbe followedprecisely.

Decimal to Inches
inches 112 = decimal
decimal 12 = inches
Temperature Conversions-
Fahrenheit= (915 * C) +32
Celsius=(F- 32) * 519
Copper TubingWall Thickness

Fraction to Decimal Eauivalent 1 I Decimal to Second Conversion I
I PLACE) I
Numerical Place Value ChartI
F o r E x a m p l e 2 , 2 6 2 . 3 5 7 . 6 1 9 8 4 4
2
THOUSANDS
bI UNITS I 1 ILI
2
3
5
MILLIONS
100,MK)
TEN
THOUSANDS
THOUSANDS
HUNDREDS
TENS
1,000,000
E
10,000
1,000
loo
10
D
1
C
1
A
6
HUNDREDTHS
9
8
4
TENTHS
I
1/10 I 0.1
1/100
THOUSANDTHS
TEN
THOUSANDTHS
HUNDRED TEN
THOUSANDTHS
MILLIONTHS
0.01
111,000
1110,000
1H00.000
111,000,000
0.001
0.0001
0.00001
0.000001

Elements of a NondestructiveExamination Symbol
Elements of a Welding Symbol
NUMBER OF EXAMINATIONS LENGTH OF SECTION TO BE
EXAMINED
REFERENCE LINE
-EXAMINE IN FIELD
SPECIFICATION OR OTHER
REFERENCE EXAMINE-ALL-AROUND
TAIL ARROW
GROOVE ANGLE: INCLUDED ANGLE OF
FINISH SYMBOL COUNTERSINK FOR PLUG WELDS
ROOT 0PENING:DEPTH OF FILLING FOR PLUG
GROOVE WELD SIZE AND SLOT WELDS
DEPTH OF BEVEL; SIZE OR STRENGTH FOR LENGTH OF WELD
CERTAIN WELDS PITCH OF WELDS
-FIELD WELD
SPECIFICATIONOR OTHER
NOT USED)
REFERENCE (OMITTEDWHEN T WELD-ALL-AROUND
TAIL ARROW
NUMBER OF SPOT, SEAM, STUD,
PLUG. OR PROJECTION WELDSA
RADIATION DIRECTIONEXAMINE ALL AROUND
Plugor Spot or Back or Flange
Fillet Slot Stud Projetiin Seam Backing Surfacrng Edge 1 Corner
FIELD EXAMINATION
/
L
GROOVE
Basic Weld Symbols
Square
--LL--- -
i
Scad
--.
-7r-
Weld all
around
V
-v---A-
FieldWeld
/--
i
Mvel
- --1'T--
Melt
~hrough
-Tee
U
--Y----A--
Consumable
Insen
(Square)
J
--Y----K-
Backing
or Spacer
(Recrangle)
Flare-V
-I/_-
-2x--
,Contour
Flare-
bevel
--LC-
--rc-
Flush
or Flat Convex Concave

Examples of Grooves
square SingleJ Single Bevel
SingleVee Double Bevel SingleU
Basic Joints (Welding) I
I Lav
' / I corner / /
w e Tee

Order of PerformingArithmetic Operations
When severalnumbers or quantitiesin a formula are connected by signs indicatingthat additions,
subtractions,multiplications, or divisions are to be made, the multiplicationsand divisions should be carried out
1,%st, in the order in which they appear,before the additions or subtractionsare performed.
Examples: 10+26X7-2=10+182-2=190
18+6+15X3=3+45=48
12+14+2-4=12+7-4=15
When it is required that certain additions and subtractionsshouldprecede multiplication's and divisions,use
is made of parentheses 0 and brackets n.
These indicatethat the calculation inside the parentheses or brackets shouldbe carriedout completeby itself
before the remaining calculations are commenced. If one bracket is placed inside of another, the one inside is first
calculated.
Examples: (6-2)X5+8=4X5+8=20+8=28
6X(4+7)+22=6X 11-22=66+22=3
2+[1OX6(8+2)-4]X2=2+[1OX6Xl0-4]X2
=2+[600-4]X2=2+596X2=2+1192=1194
The parentheses are consideredas a sign of multiplication;for example, 6(8 +2) = 6 x (8 +2).
The line or bar between the numeratorand denominatorin a fractionalexpressionis to be consideredas a
division sign. For Example,
In formulasthe multiplicationsign(X) is often left out between symbolsor letters, the values of which are to be
multiplied. Thus
ABC
AB=AXB,and-= (AXBXC)+D
D

Ratio And Proportion
The ratio between two quantitiesis the quotient obtainedby dividingthe first quantityby the second. For
example, the ration between 3 and 12is '14, and the ratiobetween 12and 3 is 4. Ratio is generallyindicatedP - *
sign (:); thus 12 :3 indicatesthe ratio of 12to 3. d
A reciprocal or inverseratio is the reciprocalor the original ratio. Thus, the inverseratio 5 :7 is 7 :5.
In a compound ratio each term is the product of the correspondingterms in two or more simpleratios.
Thus when
then the compound ratio is:
Prop is the equality of ratios. Thus,
The firstand last tenns in a proportion are called the extremes;the second and thirds, the means. The
product of the extremesis equalto the product of the means. Thus,
If third terms in the proportion are known, the remaining term may be found by the followingrules:
1)The firstterm is equalto the product of the secondand third terms, dividedby the fourth term.
2) The second term is equal to the product of the first and fourth terms, divided by the third.
3) The third term is equal to the product of the first and fourth terms, dividedby the second.
4) The fourthterm is equalto the product of the second and third tenns, dividedby the first.

Calculationof Area
Square/Rectangle = Length * Width
Circles -- w2
Triangle = Height * Base * 1/2
Sphere -- 4m2
Weld Area Calculation
Structural Welds = Length * Width (measured)
Piping Welds = Circumference(OD*7t) * Width
Socket Welds = L x W
L = ((OD at A + OD at B) / 2) *7t
W = Width of the weld is measured.
Common Symbols and Terms
3.1415
Diameter / 2
Inside Diameter
Outside Diameter
Less Than (ie 6 ~ 9 )
Greater Than (ie 9>6)
Equal To or Less Than
Equal To or Greater Than
Plus or Minus
InspectaPs Handbook

Change percent ( % ) to decimal (0.0).
Move decimal point 2 spaces to the left and drop the percent sign.,
Example: 2% = 2.0% = -02 d
Change decimal (0.0) to percent ( % ) . ..
Move decimal point 2 units to the right and add the percent sign.
Example: .43 = 43%
Change a fraction to a decimal.
Divide the numerator by the denominator.
Example: 1/2 = 1 divided by 2 = .5
Tm = Material Thickness, thickness of the thinner member
excluding reinforcements.
Ts = Specimen Thickness, thickness of the thinner member
including reinforcements.
Minimum Weld Throat Thickness = .7 x Tm
Based upon 1T X 1T

Solutionof Right-angled Triangles

Basic Illustrationof a Weld
FILLET LEG
SIZE OF WEW
1qxctoP"sHandbook

Welding Processes ha
ELECTRODE COVERING
Shielded Metal Arc Welding (SMAW)
An arc weldingprocess, which melts and
b,ins metals by heating them with an arc
oetween a covered metal electrode and the
work. Shielding gas is obtained fromthe
electrodeouter coating, often called flux. METALAND SLAG
Commonly referred to as "stick" welding. SOLIDIFIEL)SLAG
SHELDINGGASIN ON
WELD
CURRENT CONDUCTOR
WIRE GUIDE
DIRECTION AND CONTACT
Gas Metal Arc Welding (GMAW)
OFWELDING An arc welding process, whichjoins metals by heatingthem
GAS NOZZLE with an arc. The arc is between a continuously-fedfiller metal
(consumable) electrodeand the mrk piece. Shieldinggas is
supplied from an external source of inert gas, normally argon,
helium, or a mixture of the two. Commonlyreferred to as
"MIG" welding.
joins metalsby heatingthem with an arc
WIRE GUIDE 6. between a continuous,consumableelectrode
CONTACTTUBE wire and the work Shielding is obtained from a
flux containedwithin the electrode core.
Depending upon the type of flux-cored wire,
added shieldingmay or may not be provided
from externallysuppliedgas or gas mixture.
tungsten electrode, which shouldnot become part of the
L
*ompletedweld. Filler metal is normally used when welding.
Jsually helium or argon, or mixture, is used for shielding gas.
Inspector's Handbook 1-1 1

Backing Ring Common Defect Locations
CRACKING
OVERLAP SLAG/OXIDEINCLUSIONS i

u
UNDERCUT TUNGSTEN INCLUSIONS
POROSITY INCOMPLETE (LACK OF) FUSION
I CRACKING
BURN-THROUGH
ConsumableInsert CommonDefect Locations
/
INCOMPLETE (LACK OF) PENETRATION
SLAGOR UNDERCUTAT THE ROOT
TOES
CRACKING
OVERLAP SLAG/OXIDEINCLUSIONS
UNDERCU
INcLuSroNS INCOMPLETE (LACK OF) FUSION
POROSITY
I CRACKING
BAD FITUP
SLAGBETWEEN BACKING
RING AND PIPE ID
u
CONCAVITY MELT-THROUGH
BURN-THROUGH INCOMPLETE (LACK OF) FUSION 4
UNDERBEAD CRATERS CENTERLINE CREASE
OVERLAP CRACKING
UNDERCUT AT THE#OO&OTTO#
BACKING GAS LOS A% MPLETE (LACKOF) PENETMTION
CRACKING
MELT-THROUGH

Hot Tear
Primary Processing Discontinuities
IDifference in cooling rates between thin sections
and thick sections
1 surface
I
Location
Surface
Caused By
Lack of h i o n between two interceptingsurfaces
of metal as it flows into the cast
Process
:L
Casting
I Porosity
IEntrapped internal gasses
Discontinuity
Cold Shut
BlowHoles
Cavity
Microshrinkage
Inability of external gassesto escape h m the
mold
Forging
I
IFlatteningand lengtheningof discontinuities
L sdgem (bar found in parent material
( Subsurface I
Lack of enough molten metal to fill the space
createdby shrinkage
Improperlydesigned mold causingpremature
blockage at the mold gate
Surface
I Laminations(flatplate)
Lengthening of surfacecracks found in parent I Surface
I
Subsurface
Subsurface
Lap
Burst
Flatteningand lengtheningof discontinuitiesin
parent material I Subsurface (
F r I L a C k o f Fusion IIncomplete weld I Surface
(inner and outer)
Folding of metal in a thin plate on the surface of
the forging
Forging at impropertemperature
Surface
Surfaceor
Subsurface
Seams
pipe
IPresent in the parent material (roundbar stock)
Laminations
Gouges
Seamless
Pipes and
Tubes
ISizing mandrel dragging
Present in the parent material (sheet or parent
material)
1- Seams
Subsurface
Slugs
Present in parent material ( Surface 1
Porosity ( Present in parent material
,
Metal buildup on piercingmaterial
Inner
Surface
Inspector's Handbook 1-13
I
I
w
1
Galling (cracks) Impropermetal flow through the die Surface

I Heat Treating
FinishProcessing Discontinuities
Explosive
Forming
Process
Grinding
Welding
StressCracks
Discontinuity
Cracks
Cracks and Tears
Crater Cracks (star,
transverse,and
longitudinal)
Caused By
Excess localized heat created between the
grinding wheel and the material
StressCracks
Location
Surface .-/
- -
Porosity
Slag Inclusions
TungstenInclusions
I
Lack of Penetration
Lack of Fusion
Undercut
Overlapping
I
Extreme deformationoverstresses the material I surface
I
~ -
Stressbuilt up by improper processing-unequal
heating and cooling
Improper use of heat source
Surface
Surfaceor
I Subsurface I
Entrapped gasses
Stressesbuilt up by the weld contraction(if
material is restrained)
Surfaceor
I Subsurface
Surface
Excessive current used during GTAW
Incomplete cleaningof slag fiomthe weld
betweenpasses
I Subsurface I
Surfaceor
Subsurface
Improper welding technique Surfaceor
I Subsurface I
Improperwelding technique Subsurface 1
Improperwelding technique I surface (
Weld overlapsparent material -not b e d I surface
I
I Bending Cracks
I
- -
Overstress of material
I Machining 1 Tears IWorkingwith dull tools or cutting too deep 1 Surface
I
I Pz?,"I Cracks
1 Electroplating
I Cracks
Inspector's Harrdbook
Relief of internal stress
Relief of internal stress
Surface
Surface

Dial IndicatingCalipers
1.VerifLthe caliper's calibration date is current, and clean all dirt fiom measuring faces. Performuser
calibration ondial indicator, ensure reading is zero, and tightenthe bezel clamp as needed.
2. Adjust measuring faces, contactpoints, to fit item being measured.
3. Apply f m pressure to fine adjustingroll and ensure measuringcontacts are in contact with the material
being measured.
4. Apply lock screw and read measurement in place if practical. If not, remove caliperscarefullyto prevent
false measurements.
Micrometer
PART TO BE MEASURED
GRADUATIONS
TO BE READ
FRAME
READING LINE
1.Verifj.that the micrometer's
calibration date is current, and cleanall
dirt from measuringcontacts. VEPN~ER
C
.000/
G I R H R T / O N S
IS
2. Attach ball if measuringcurved
surfaces.
3. Adjust micrometerto fit the item s-L fCYrC
being measured, do not spin frame to -too 4%vo.Olb
GRRDVRT/O/YS
adjust the micrometer.
4. Slipthe micrometer overthe areato be measured by placingthe anvilf d y againstthe material and slowlyturn
the thimble clockwiseuntil spindle is firmly against the material. Then turn the ratchet three clicks to be sure equal
pressure is applied.
5. Take reading in place, or set the lockingnut and remove fiomthe item. Determinereading on scale and note
w
accordingly. Do not forget to minus the ball measurement if used.

AXIS
PITCH
DIAMETER
Tap and Drill Size Chart
7
THREAD
1 SIZE
CREST
R m

"w
L'
L
Day
I
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Dec
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
Nov
305
306
307
308
309
310
311
-312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
Oct
274
275
276
277
278
279
280
281-
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
Sep
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
(Perpetual)
Aug
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
July
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
Date Calendar
June
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
Julian
May
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
Apr
091
092
093
094
095
096
097
098
099
100
101
102
103
104
105
106
107
108
109
110
111
112
I13
114
115
116
117
118
119
120
Mar
060
061
062
063
064
065
066
067
068
069
070
071
072
073
074
075
076
077
078
079
080
081
082
083
084
085
086
087
088
089
090
Feb
032
033
034
035
036
037
038
039
040
041
042
043
044
045
046
047
048
049
050
051
052
053
054
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059
Day
1
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15
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27
28
29
30
. 31
Jan
0 0 1
002
003
004
005
006
007
008
009
010
011
012
013
014
015
016
017
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019
020
021
022
023
024
025
026
027
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029
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031

1-18 Inspector's Handbook
Day
1
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5
6
7
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9
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I 1
12
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Jan
001
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Feb
032
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Mar
061
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Apr
092
093
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096
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102
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Julian
May
122
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135
136
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Date Calendar
June
153
154
155
156
157
158
159
160
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162
163
164
165
166
167
168
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170
171
172
173
174
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176
177
178
179
180
181
182
(Leap
July
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
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200
201
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213
Year)
Aug
214
215
216
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228
229
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232
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Sep
245
246
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254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
Dec
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
Oct
275
276
277
278
279
280
281
282
283
284
285
2 8 6
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
Nov
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
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330
331
332
333
334
335
i
C
1 *
2
3
4
5
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7
8
9
I 0
I 1
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15 '
l b ,
v
17
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3 . 4

Chapter 2 -Visual Inspection
Common Definitions and Examples
r Aligned rounded indications
i/ Four or more indications in a line, where each is separated
fromthe adjacent indication by less then 1/16inch or D, whichever
is greater,where D is the major diameter of the larger of the adjacent
indication.
Arc strike
Any localized heat-effected zone or changein the contour of
the surfaceof the finished weld or adjacent base metal resulting from
m atc or heat generatedby the passage of electricalenergybetween
the surfaceof the finished weld or base metal and a current source,
such as welding electrodesor magnetic particle inspectionprods.
Burnthrou~h
A void or open hole that extends through a backing ring, strip, fused root, or adjacent base metal.
Burst
A rupture causedby forging at improper temperatures. Bursts may be either internal or externalto the
surface.
Cold shut
The result ofpouring metal over solidifiedmetal.
/
Trackor tear
+ A linear rupture of metal under stress.
Craterpit
An approximatelycircular surfacecondition exceeding into
the weld in an irregular manner caused by insufficient filler metal at
theweld stop.
Defect
One or more flawswhose aggregate; size, shape, orientation,
location, or properties do not meet the specified acceptancecriteria
and are rejectable.
Discontinuity
Any interruption in the normal physical structure or
configurationof a part, which will cause a detectable indicationor
signal when nondestmctively examined.
Evaluation
A review, following interpretationof the indicationsnoted, to determine whether they meet specified
cceptance criteria.
L

False indication
An indicationthat is interpretedto be causedby a condition other than a discontinuityor imperfection.
Heat checks
Fissures or tears in the weld heat affected zone of material containinglow meltingpoint.
Indicatic
I
ure of quality characteristicfrom its intended condition.
Ln
Zvidence of a discontinuitythat requires interpretationto determine its significance.
ete fusion I,ack of completefusion of someportion of the metal in a
Weldjolnt with adjacent metal. The adjacentmetal may be either
base metal or previously deposited weld metal, or consumable insert.
Incompletepenetration
Lack of penetration of the weld through the thickness of the
joint, or penetrationwhich is lessthanspecified.
Interpretation
The determination of whether indicationsare relevant,
nonrelevant, or false.
Lap (forginas)
Folding of metal on the surface of the forging, usually occ ' u
when some of the forgingmetal is squeezedout between the two dies.
Linear indication
An indication in whichthe lengthis equalto or
greaterthanthree times the width.
Melt through
A convexor concave irregularityon the surfaceof a backing ring or strip, fusedroot, or adjacentbase metal
resulting from fusion completely through a localized region but without developmentof a void or open hole.
Non-linear rounded indications
Indication whose length is less thanthree times its width.
Nonrelevant indications
An indicationthat is causedby a condition or type of discontinuitythat is not relevant.

Oxidation
A condition resulting from partial or completelack of inert gas shieldingof a surfacewhich is heated
ring weldingresulting in formation of oxide on the surface. This condition may range fiom slight oxidation
idenced by a multicolored or tightly adheringblack film to the extreme of a very rough surfacehaving a
crystalline appearance.
Porosity
Gas pockets or voids in weld metal or castings.
Quenchcrack
A crack formed as a result of the& stressesproducedby
rapid cooling fiom a high temperature.
Root surfaceconcavity
A depression on the root surfaceof a weld which may be due
to gravity, internalpurge, or shrinkage.
Root surface centerlinecrease or shrinkage
An intermittentor continuousperipheral centerline concavity formed on the root surface.
Root undercut
A groove in the internal surfaceof a base metal or backingring or strip alongthe edge of the root of the
weld.
Shrinkage
Void, or voids, that may occur in molten metal due to
contractionduring solidification.
s&
Non-metallic solidmaterial entrapped in the weld metal,
between weld metal and base metal, or in a casting.
Tungsten inclusion
Tungsten entrapped in the weld deposit.
Undercut
A groove melted into the base metal at the toe of the weld and left unfilled by weld metal.
Unfusedchaplet
A metal supportused in the castingprocess, which has not
fused with casting material.
Weld spatter
Metal particles which deposit on the surface of the weld or
adjacent base metal duringwelding and which do not form a part of
theweld.

Chapter 3 - Liquid Penetrant Testing
CommonTerms and Definitions
Alkaline
L Any solublemineral salt or mixtures of salt capable of neutralizing acids.
Angstrom Unit (A)
A unit of length equal to lo8cm and used to expresswavelengths of light; i.e., electromagneticradiation.
Background
The surfaceupon which an indication is viewed. It may be the natural surfaceof the test article or it may be
the developercoating on the surface. This background may containtraces of unremoved penetrant (fluorescentor
visible), which, if present, can interfere with the visibility of indications.
Background Fluorescence
Fluorescent residues observed overthe general surface of the test article duringfluorescent penetrant
E h
Term used colloquially to designate the liquid penetrant inspectionmaterials into which test articles are
immersed during inspectionprocess.
Black Li~ht
Light radiation in the near ultraviolet range of wavelengths (3200 to 4000 A), just shorterthan visible light.
Black Light Filter
L A filter that transmits black light while suppressingvisible light and hard ultravioletradiation with
wavelengths less than 3200 angstroms.
Bleedout
The action of the entrappedPenetrant in spreading out from surface discontinuitiesto form an indication.
Blotting
The action of the developerin soakingup the entrappedpenetrant from d a c e discontinuities to form an
indication.
CapillaryAction or Capillarity
The tendency of liquidsto penetrate or migrate into small openings such as cracks,pits, or fissures.
CarrierFluid (Vehicleor Medium)
A fluid in which liquid penetrant inspection materials are dissolved or suspended.
Clean
Free from interferingsolid or liquid contaminationon the d a c e .
ComparativeTest Block
An intentionally crackedmetalblock having two separatebut adjacent areas for the application of different
penetrants sothat a d<ect comparisonof their relative effeativeness canbe obtained. Can alsobe used to evaluate
?enetranttest techniques and test conditions.

Contact Emulsifier
An emulsifierthat begins emulsifyingpenetrant upon simple contact with the penetrant; usually oil-base
(Lipophilic).
Contrast w
The difference in visibility (brightness or coloration)between an indication and the surroundingsurface.
DarkAdaptation
The adjustment of the eyeswhen one passes from a bright to a darkened area.
Detergent Remover
A penetrant remover that is a solution of a detergent in water. Also Hydrophilic Emulsifjer.
Developer
A materialthat is applied to the test article surfaceafter excess penetrant has been removed and that is
designedto enhancethe penetrantbleedout to form indications. The developermay be a finepowder, a solution
that dries to a fine powder, or a suspension(in solvent, water, alcohol, etc.) that dries leavingan absorptive film on
the test surface.
DevelopingTime
The elapsedtime necessary for the applied developerto bring out indications from penetrant entrapments.
Also calledDevelopment Time.
Dragout
Thecanput or loss of penetrant materials as a result of their adherence to the articles being processed.
Drain Time w
That portion of the penetrant inspectionprocess duringwhich the excesspenetrant, emulsifier, detergent
remover, or developeris allowed to drain fiom the test article.
Dry Developer
A fine, dry powder developerthat does not employ a carrier fluid.
DryingOven
An oven used for drying test articles.
Drvinn Time
A time allottedfor a test articleto dry.
DuaLresponsePenetrant
A penetr- that contains a combinationof visible and fluorescentdyes.
Dwell Time
The total time that the penetrant or emulsifier is in contact with the test surface, includingthe time required
for application and the draintime. Also see EmulsificationTime.
ElectrostaticSpraying
A technique of spraying wherein the material being sprayed is given a high electrical charge while the test
axticle is grounded. u

Emulsification Time
The period of time that an emulsifieris permittedto combine with the penetrant prior to removal. Also
calledEmulsifierDwell Time.
Tmulsifier
'v
A liquid that combines with an oily penetrant to make the penetrant water-washable. Also seeHydmphilic
Emulsifier &d LipophilicEmulsifier.
Flash Point
The lowest temperature at whicha volatile, flammableliquid will give off enough vapor to make a
combustibleexplosivemixture in the air space surroundingthe liquid surface.
Fluorescence
The emissionof visible radiationby a substanceas a result of, and only during, the absorptionof black light
radiation.
Fluorescent Dye Penetrant
An inspectionpenetrant that is characterized by its abilityto fluorescewhen excitedby black light.
Halogen (Halonenous)
Any of four very active nonmetallic elements; chlorine, iodine, fluorine andbromine.
HydrophilicEmulsifier
A water-base agentthat, when appliedto an oilypenetrant, renders the penetrant water-washable. Canbe
used as a Contact Emulsifier, but more often the emulsifier is added to the water rinse and accompaniedby some
form of mechanical agitationor scrubbingto remove excess penetrant. Sometimes called a Hydrophilic Scrubber.
-~ e a kTesting
A technique of liquidpenetranttesting in which the penetrant is appliedto one side of the surface while the
other side is inspected for indicationsthat would indicate a through-leak or void.
LipophilicEmulsifier
An oil-base agentthat, when appliedto an oilypenetrant, renders the penetrant water-washable. Usually
applied as a ContactEmulsifier.
Near SurfaceDiscontinuity
A discontinuity not open to, but located near, the surfaceof a test article.
,Nonaqueous Wet Develowr
A developer in which the developingpowder is applied as a suspensionin a quick-drying solvent.Also
called Solvent Developer.
Penetrability
The property of a penetrant that causes it to find its way into very fine openings, such as cracks.
Penetrant
A liquid (sometimes gas) capable of enteringdiscontinuitiesopento the surface, and which is adaptedto
the inspection process by being made highly visible in small traces. Fluorescentpenetrants fluorescebrightly under
black light while the visible penetrants are intensely colored to be noticeable under visible light.
L

Post-emulsification Penetrant
A penetrant that requires the application of a separateemulsifierto render the surfacepenetrantwater-
washable. Also can be removed by applying a solvent remover.
Precleaning 4
The removal of surfacecontaminants or smeared metal from the test article so that they cannot interfere
with the penetrant inspectionprocess.
Ouenchin~of Fluorescence
The extinctionof fluorescenceby causes other than removal of black light (the excitingradiation).
Resolution
The property of a test systemthat enables the separation of indications of closeproximity in a test article..
Rinse-
The process of removing liquid penetrant inspection materials from the surface of an articleby washing or
floodingwith another liquid-usuallywater. Also called Wash.
See-ability
The characteristic of an indication that enablesth: observerto see it against the conditionsof background,
outside light, etc.
Self-developinnPenetrant
A penetrant not requiring the use of a developer. Useful for production work in the detectionof gross
discontinuities.
Sensitivity
.'v
The ability ofthe penetrant process to detect minute surface discontinuities.
Solvent Removed
A penetrant-removal technique wherein the excesspenetrant is washed or wiped from the test surfacewith
a solvent remover.
SolventRemover
A volatile liquid used to remow excess surfacepenetrant from the test article. Sometimes called Penetrant
Remover.
SurfaceTension
That property of liquidswhich, due to molecular forces, tends to bring the contained volume into a form
havingthe least superficialarea.
Viscosity
The stateor degree of being viscous. The resistance of a fluid to the motion of its particles.
Visible Dye Penetrant
An inspection penetrant that is characterized by its intense visible color-usually red. Also called Color
Contrast orNonfluorescent Penetrant.
Water-solubleDeveloper
A developer in which the developerpowder is dissolved in a water carrier to form a solution.Not a
d
suspension.

Water-suspended Particle Developer
A developer in which the developerparticles are mixed with water to firm a suspension.
Water-wash
L A penetrant-removal techniquewherein excesspenetrant is washed or flushed fromthe test surfacewith
water.
Water-washablePenetrant
A type of penetrant that contains its own emulsifier,making it water-washable.
Water Tolerance
The amount of water that a penetrant, emulsifier,or wet developer can absorbbefore its effectiveness is
impaired.
Wet Developer
A developer in which the developerpowder is applied as a suspensionor solution in a liquid-usually water
or alcohol.
Wetting Ability
The ability of a liquid to spread out spontaneously and adhere to the test article's surfaces.

w
(MAX# OF INDICATIONSl36)X ACTUALAREA =NEW MAX# OF INDICATIONS
I
- I .I00 .0079
Area = m2

Penetrant Wetting Characteristics
Inspector's HandGook

Chapter 4 -Magnetic Particle Testing
Common Definitions and Examples
-.& gap
When a magnetic circuit contains a small gap, which the magnetic flux must cross, the space is referred to
as an air gap. Cracks produce small air gaps on the surfaceof an article.
Alternatingcurrent
Electric current periodicallyreversing in polarity or direction of flow.
AmDere
Theunit of electrical current. One ampere is the current that flows through a conductor having a resistance
of one ohm at a potential of one volt.
Ampere turns
Theproduct of the number of turnsin a coil and the number of amperes flowingthrough it. A measure of
the magnetizingor demagnetizing strengthof the coil.
W h
The suspensionof iron oxide particles in a liquid vehicle (light oil or water).
J
Black light
Radiant energy in the near ultraviolet range. This light has a wavelength of 3200 to 4000 angstrom units
(A), peaking at 3650 A, on the spectrum. This between visible light and ultraviolet light.
$lack light filter
A filter that transmitsblack light while surprisingthe transmission of visible light and harrml ultraviolet
radiation.
Carbon steel
Steelthat doesnot contain significant amounts of alloyingelements other than carbon and maganese.
Carrier fluid
The fluid in which fluorescent and no* fluorescentmagnetic particles are suspendedto facilitate their
application in the wet method.
Central conductor
An electrical conductor that is passed throughthe opening in a ring or tube, or any hole in an article, forthe
purpose of creating a circular field in the ring or tube, or around the hole.
Circular field
See Field, Circular Magnetic.
Circularmagnetization
A method of inducing a magnetic field in an article so that the magnetic lines of force take the form of
concentricrings about the axisof the current. This is accomplishedby passing the current directly throughthe
article or through a conductor which passes into or through a hole in the article. The circularmethod is applicable
fort h detection of discontinuitieswith axes approximately parallel to the axis of current through the article.

Coercive force
The reverse magnetizing force necessaryto remove residual magnetismin demagnetizing an article.
Coil shot
A pulse of magnetizing currentpassed through a coil surroundingan articleforthe purpose of longid -magnetization.
Contact headshot
The electrode, faed to the magnetic particle testing unit, through which the magnetizing current is drawn.
Contactpads
Replaceable metal pads, usually of copperbraid, placed on contactheads to give good electrical contact
thereby preventing damage to the articleunder test.
1
Continuousmethod
An inspection method in which ample amounts of magnetic particles are applied, or arepresa on the
piece, during the time the magnetizingcurrent is applied.
Core-
That part of the magnetic circuit that is within the electrical winding.
Curiepoint
The temperature at which ferromagneticmaterials can no longer be magnetized by outside forces, and at
which they lose their residual magnetism: approximately 1200to 1600' F (646 to 871° C) for many metals.
Current Flow Technique
A technique of circular magnetizationin which current is passed through an articlevia prods or contact 4
heads. The current may be alternating,half-wave rectified, rectified alternating, or direct.
C m t Induction Technique
A technique of magnetizationin which a circulating current is induced in a ring-shaped componentby a
fluctuating magnetic field.
Demamethtion
The reduction in the degree of residualmagnetismto an acceptablelevel.
Diamagnetic
Materialswhose atomic structurewon't permit any real magnetization. Materials suchasbismuth and
copperare diamagnetic.
Diffused Indications
Indications that are not clearly defined, such as indications of subsurface defects.
Direct ContactMagnetization
A magnetic particle testing technique in which current is passed throdgh the test article. These include
headshots andprod shots.
Direct Current
An electrical current, which flows steadily in one direction
4-2 Inspector's Handboak

DistortedField
A field that does not follow a straightpath or have a uniform distribution. Thisoccursin irregularly shaped
objects.
b
Dry Medium
Magnetic particle inspection in which the particles employed are in the dry powder f o m
Dry Powder
Finely divided ferromagneticparticles suitably selected and prepared for magneticparticle inspection.
Electromagnet
A magnet created by inserting a suitablemetal core within or near a magnetizing field formed by passing
electriccurrent through a coil of insulatedwire.
Etching
Theprocess of exposing subsurfaceconditionsof metal articlesby removal of the outside surfacethrough
the use of chemicalagents. Due to the action of the chemicals in eating away the surface,various surfaceor
subsurfaceconditions are exposed or exaggerated and made visibleto the eye.
Ferromagnetic
A term applied to materials that can be magnetized and strongly attracted by a magnetic field.
Field, CircularMametic
Generally the magnetic field in and surroundingany electrical conductor or articleresulting from a current
being passed through the conductoror article or fiomprods.
.field,Longitudinal Magnetic
A magnetic field wherein the flux lines traverse the component in a directionessentiallyparallel with the
axis of the magnetizing coil or to a line connectingthe two poles at the magnetizingyoke.
Field, Magnetic
The space within and surroundinga magnetized article, or a conductor carryingcurrent in which the
magnetic force is present.
Field, MagneticLeakwe
The magnetic field that leaves or entersthe surface of an article at a magnetic pole.
Field. Multidirectional
A magnetic field that is the result of two magnetic forces impressedupon the same area of a magnetizable
object at the sametime-sometimescalled a "vector field."
Field, Residual Mametic
The field that remains in magnetizable material after the magnetizing force has been removed
Flash Magnetization
Magnetizationby a current flow of very brief duration.
Fluorescence
W ,J The emission of visibleradiationby a substanceas the result of and only duringthe absorptionof black
light radiation.

FluorescentMagnetic Particle Inspection
The magnetic particle inspection process employing a finely divided fluorescent ferromagneticinspection
medium that fluoresceswhen activated by black light.
V
Flux Density
The normal magnetic fluxper unit area It is designatedby the letter "B" and is expressed in telsa (SI units)
or gauss (cgs units).
FluxLeakage
Magnetic lines of force which leave and enter an article at poles on the surface.
FluxLines
Imaginary magnetic lines used as a means of explaining the behavior of magnetic fields. Their conception
is based on the pattern of linesproduced when iron filings are sprinkled over a piece of paper laid over a
permanent magnet. Also called Lines of Force.
Flux Penetration,Magnetic
The depth to which a magnetic flux is present in an article.
Furring
Buildup orbristling of magnetic particles due to excessivemagnetizationof the article.
Gauss
The unit of flux density.Numerically, one gauss is one line of fluxper square centimeterof area and is
designated by the letter "B." -
w
Head Shot
A shortpulse of magnetizing current passed through an articleor a central conductor while clamped
between the head contacts of a stationarymagnetizing unit for the purpose of circularly magnetizingthe article.
Heads
The clamping contacts on a stationarymagnetizingunit.
Horseshoe Magnet
A bar magnet bent intothe shape of a horseshoe sothat the two poles are adjacent. Usuallythe term applies
to a permanent magnet.
Hysteresis
The lagging of the magnetic effect when the magnetic force acting upon a ferromagneticbody is changed;
the phenomenon exhibited by a magnetic system wherein its state is influenced by its previous magnetic history.
HysteresisLoop
A curve showing the flux density, "B," plotted as a hction of magnetizingforce, "H." As the magnetizing
force is increased to the saturationpoint in the positive,negative, and positive direction sequentially,the curve
forms a characteristicS-shaped loop. Interceptsof the loop with the "B" and "H" axes and the points of maximum
and minimum magnetizing force define important magnetic characteristicsof the material.
Inductance w
The magnetismproduced in a ferromagneticbody by some outsidemagnetizing force. The magnetism is
not the result of passing current throughthe article.
4-4 Inspector's Randbook

Leakage Field
The magnetic field forced out into the airby the distortionof the fieldwithin an article.
',ifit Intensitv
L., The light energy reaching a unit of surface areaper of time.
LonnitudinalMagnetization
The process of inducing a magnetic field into the article such that the magnetic lines of force extending
through the article are approximatelyparallel to the axis of the magnetizing coil or to a line connecting the two
poles when yokes (electromagnets)are used.
Magnet, Permanent
A highly-retentivemetal that has been strongly magnetized; i.e., the alloy Alnico.
Mmetic Field Indicator
An instrument designed to detect andlor measure the flux density and polarity of magnetic fields.
MagneticField Strength
The measured intensity. of a magnetic field at a point alwaysexternal to the magnet or conductor;usually
expressed in amperes per meter or oersted (Oe).
Magnetic Material
Those materials that are attracted by magnetism.
MagneticParticles
Finely divided ferromagneticmaterial.
i/
Magnetic Particle Inspection
A nondestructiveinspection method for locating discontinuitiesin ferromagneticmaterials.
Magnetic Poles
Concentrationof flux leakage in areas of discontinuities,shape changes, permeability variations, etc.
MagneticWriting
A form of nonrelevant indications caused when the suface of a magnetizedpart comes in contactwith
anotherpiece of ferromagneticmaterial that is magnetized to a different value.
MagnetizingCurrent
The flow of either alternating, rectifiedalternating,or direct current used to induce magnetism into the
articlebeing inspected.
Magnetizin~Force
,Themagnetizing field applied to a ferromagneticmaterial to induce magnetization.
Medium
The fluid in which fluorescent and nonfluorescent magnetic particles are suspendedto facilitatetheir
application in the wet method.
b Jear SurfaceDiscontinuitv
A discontinuitynot open to, but locatednear, the surface of atest article.

Oersted
A unit of field strength, which produces magnetic inductionand is designated by the letter "H."
/
Paramagnetic 4
Materials which are slightly affected by a magnetic field. Examples are chromium, manganese, aluminun,
and platinum. A small group of these materials are classified as ferromagnetic.
Permeability
The ease with which the lines of force are able to pass through an article.
Pole-
The area on a magnetized article fiom which the magnetic field is leaving or returning to the article.
Prods
Hand-held electrodesattachedto cablesused to transmit the magnetizingcurrent from the sourceto the
articleunder inspection.
RectifiedAlternatingCurrent
Alternating current, which has been converted into direct current.
Reluctance
The resistance of a magnetic material to changes in magnetic field strength.
Residual Magnetism
The amount of magnetism that a magnetic material retains after the magnetizingforce is removed. Also
called "residual field" or "remanence." w
Residual Technique
A procedure in which the indicating material is applied after the magnetizing force has been discontinued.
Retentivity
Theabilityof a ~mterialto retain a certainportion of residual magnetization. Also known as rernanence.
Saturation
The point at which increasingthe magnetizing force produces no Mher magnetism in a material.
Sensitivity
The capacityor degree of responsivenessto magnetic particle inspection.
SettlingTest
A procedure used to determine the concentrationof magneticparticles in a medium or vehicle.
Skin Effect
The description given to alternating current magnetization due to its containmentto the surfaceof atest
article.
Solenoid (Coil)
An electricconductor formedinto a coil often wrapped around a central core of highly permeable mate ,,

Suspension
The correct term applied to the liquidbath in which the ferromagneticparticles used in the wet magnetic
particle inspectionmethod &e suspended.
>
Lrest Article
An articlecontaining known artificialor natural defectsused for checkingthe efficiency of magnetic
particle flaw detectionprocesses.
Wet Medium
An inspection employingferromagneticparticles suspended in a liquid (oil or water) as a vehicle.
Yoke
A U-shaped or C-shaped piece of highly permeable magneticmaterial, either solid or laminated, sometimes
with adjustablepole pieces (legs) amundwhich is wound a coil carrying the magnetizing current.
Yoke Magnetization
A longitudinalmagnetic fieldinduced in an articleor in an area of an articleby means of an external
electromagneishaped likea yoke.
Longitudinal MagnetizationMathFormula
45,000 (+/- lo?!)
AT =
W)
A =ampere
T =turns of the coil
L = length of the item
D =diameter or cross section of the item
The minimum UDratio is 2
The maximum L used in calculations is 20 inches

Common Types of Magnetization
CentralConductor (circular) Horse shoe (longitudinal)
Coil Shot (longitudinal)
Yoke (longitudinal)
Discontinuities
Theory: "Right-Hand Rulen
CURRENT
FLOW

Hysteresis Curve
B+ (FLUXDENSITY)
0-A = Referred to as the virgin curve
L/
A = Saturationpoint
-
B = Residual field
0-C = Coercive force
D = Reverse saturationpoint
E = Reverse residual field
0-F = Reverse coercive force
H- (MAGNETIZINGFORCE OF
OPPOSITE POLARITY TO H+) H= (MAGNETIZINGFORCE)
R (FLUXDENSITY OF
OPPOSITE POLARITY TO B+)
SLENDERLOOP WIDE LOOP
HIGH PERMEABILITY LOW PERMEABILITY
LOW RENTENTIVITY HIGH RENTENTMTY
LOW COERCIVEFORCE HIGH COERCIVEFORCE d
LOW RELUCTANCE HIGH RELUCTANCE
LOW RESIDUAL MAGNETISM HIGH RESIDUAL WU3FETISM
Inspector's Hadbook

MagneticParticleField Indicator (Pie Gage)
Eight low carbon steelpie
sections,furnacebrazed
Artificialflaw (all segment
1in. interfaces)
,' I 'I '
I Nonferroushandle of any
/J
Convenient length
Copperplate
0.010 in t0.001 in
thick 7
Braze weld or mechanically
I
attach nonferroustrunnions

Chapter 5 -Ultrasonic Testing
Common Terms and Definitions
--scan Display
A dimlav in which the received signal is displayed as a vertical displacement fiom the horizontal sweep
time trace, wkl; the horizontaldistancebetween a& G o signalsrepresentsthe sound path distance(or time of
travel) between the two.
Absorption Coefficient, Linear
The fractionaldecrease in transmitted intensityper unit of absorberthickness. It is usually designatedby
the symbol and expressed in units of cml.
Acceptance Standard
A control specimen containingnatural or artificialdiscontinuitiesthat are well defined and, in size or
extent, similarto the maximum acceptable in the product. Also may refer to the document defining acceptable
discontinuity size limits.
Acoustic Impedance
The factor which controlsthe propagationof anultrasonicwave at a boundary interface. It is the product of
the material density and the acoustic wave velocity within that material.
Amplifier
A device to increase or amplify electrical impulses.
Amplitude. Indication
b. The vertkal height of a received indication, measured fiombase-to-peak or peak-to-peak.
Angle Beam Testing
A testing method in which trammissionis at an angle to the sound entry surface.
Amle of Incidence
The angle between the incident (transmitted)beam and a normal to the boundary interface.
Angle of Reflection
.
The angle between thereflected beam and a normal to the boundary interface. The angle of reflection is
equalto the angle of incidence.
Angle of Refraction
The angle betweenthe refractedrays of an ultrasonic beam and the normal (or perpendicular line) to the
rehcting surface.
Angle Transducer
A transducerthat transmits or receives the acoustic energyat an acute angleto the surfaceto achieve a
specificeffect suchup the settingup of shear or surfacewaves in the part being inspected.
Anisotropic
A condition in which properties of a medium (velocity, for example) vary accordingto the direction in
,,vhich they are measured.

Array Transducer
A transducermade up of severalpiezoelectricelements individuallyconnected so that the signalsthey
transmit or receive nay be treated separatelyor combined as desired.
s-,
Attenuation Coefficient
A factorwhich is determined by the degree of scatteror absorptionof ultrasound energyper unit distance
traveled.
Attenuator
A device for measuring attenuation, usually calibrated in decibels (dB).
B-scan Display
A cathode-ray tube display in which the received signal is displayed as an illuminated spot. The face of the
CRT represents the areaof a verticalplane through the material. The display shows the location of a discontinuity,
as it would appear in a vertical section view through the thickness directionof the material.
Back Reflection .
The signalreceived fromthe back surfaceof a test object.
Back Scatter
Scattered signalsthat are directed back to the transmitterlreceiver.
BackgroundNoise
Extraneous signals caused by signal sources within the ultrasonic testing system, including the material in
test.
w
Barium Titanate (PolycrystalliieBarium Titanate -Barn3)
A ceramictransducer material composed of many individual crystals fired together and polarized by the
applicationof a dc field.
Baseline
Thehorizontal line acrossthe bottom of the CRT createdby the sweep circuit.
Basic.Calibration
The procedure of standardizingan instrument using calibration reflectors described in an application
. document.
Bi-modal
The propagation of sound in a test article where at least a shear wave and a longitudinalwave exists. The
operation of angle beam testing at less than first critical angle.
BoundaryIndication
A reflection of an ultrasonicbeam from an interface.
Broad Banded
Having a relatively wide frequencybandwidth. Used to describe pulses which display a wide frequency
spectnun and receiverscapableof amplifyingthem.
4

C-scan
A datapresentation method yielding a plan (top) view through the scannedsurface of the part. Through
gating, only indications arising fromthe interior of the test object are indicated.
X/
",libration
To determine or mark the graduations of the ultrasonicsystem's displayrelativeto a known standard or
reference.
Calibration Reflector
A reflector with a known dimensioned surface establishedto provide an accurately reproducible reference.
Collimator
An attachment designed to reduce the ultrasonicbeam spread.
Compensator
An electricalmatching network to compensate for circuit impedancedifferences.
CompressionalWave
A wave in which the particle motion or vibration is in the same directionas the propagated wave
(longitudinalwave).
Contact Testing
A techniqueof testing in which the transducer contacts the test surface, either directly or through a thin
layer of couplant.
Contact Transducer
A transducerwhich is coupledto a test surface either directly or through a thinfilm of couplant.
L.
ContinuousWave
A wave that continueswithout interruption.
Contracted Sweep
A contraction of the horizontal sweep on the viewing screenof the ultrasonic instrument. Contractionof
this sweeppennits viewing reflections occurring over a greater sound-pathdistance or durationof time.
Comer Effect
The strongreflectionobtained when an ultrasonicbeam is directed toward the inner section of two orthree
mutually perpendicular surfaces.
Couplant
A substance used between the face of the transducer and test surfaceto permit or improvetransmission of
ultrasonic energy acrossthis b o u n w or interface. Primarily used to remove the air in the interface.
Critical An~le
The incident angle of the sound beam beyond which a specificrefracted mode of vibration no longer exists.
CrossTalk
An unwanted condition in which acousticenergy is coupled fromthe transmittingcrystal to the receiving
.,pystalwithout propagating alongthe intendedpath throughthe material.
Ld

Damping (transducer)
Limiting the durationof vibration in the searchunit by eitherelectrical or mechanicalmeans.
Dead Zone
The distance in a material from the sound entry surfaceto the nearest inspectable sound path. 4
Decibel(dB)
The logarithmic expressionof a ratio of two amplitudesor intensitiesof acousticenergy
Delamination
A laminar discontinuity, generally an area of unbonded materials.
Delay Line
A material (liquid or solid)placed in front of a transducerto use a time delay between the initialpulse and
the fiont surfacereflection.
Delayed Sweee
A means of delayingthe startof horizontal sweep, hereby eliminatingthe presentation of early response
data.
Delta Effect
Acoustic energyre-radiated by a discontinuity.
Detectability
The ability of the ultrasonic systemto locate a discontinuity.
Difiction
The deflection, or "bending," of a wave front when passing the edge or edges of a discontinuity.
Diffise Reflection
Scattered, incoherentreflections causedby rough surfaces or associateinterfacereflection of ultrasonic
waves from irregularities of the same order of magnitude or greaterthan the wavelength.
Discontinuity
An interruptionor change in the physical structure or characteristicsof a material.
Dispersion, Sound
Scatteringof an ultrasonicbeam as a result of diffuse reflectionfrom a highly-irregular surface.
Distance Amplitude CorrectionPAC)
Compensation of gain as a function of time for difference in amplitudeof reflections fiom equal reflectors
at differentsound travel distances. Also referred to astime corrected gain (TCG),time variable gain (TVG) and
sensitivitytime control (STC).
Divergence
Spreading of ultrasonic waves after leaving searchunit, and is a functionof diameter and frequency.
Dual-Element Technique
The technique of ultrasonictesting using two transducerswith one acting as the transmitter and one as f .&
receiver.

Dual-Element Transducer
A singletransducerhousing containing two piezoelectric elements,one for transmitting and one for
receiving.
zffective Penetration
The maximum depth in a material at which the ultrasonic transmissionis sufficientfor proper detectionof
discontinuities.
ElectricalNoise
Extraneous signalscausedby externallyradiated electricalsignalsor from electricalinterferenceswithin
the ultrasonic instrumentation.
Electromametic Acoustic Transducer(EMAT)
A deviceusing the magneto effect to generate and receive acoustic signals for ultrasonic nondestructive
tests.
Far Field
The regionbeyond the near field in which areas of high and low acoustic intensity cease to occur.
First Leg
The sound path beginning at the exitpoint of the probe and extendingto the point of contactoppositethe
examination surfacewhen performing angle beam testing.
Focused Transducer
A transducerwith a concave facewhich convergesthe acousticbeam to a focal point or line at a d e f d
distance fromthe race.
LZ
Focusing
Concentrationor convergenceof energy into a smallerbeam.
Frequency
Number of completecycles of a wave motion passing a given point in a unit time (1 second); number of- - -
times a vibration is repeated at the same point in the same directionper unit time (usually per second).
Gate-
An electronicmeans to monitor an associated segmentof time, distance, or impulse.
Ghost
An indication which has no direct relation to reflected pulses fromdiscontinuitiesin the materials being
tested.
Emz(Hz)
One cycleper second.
Horizontal Linearity
A measure of the proportionality between the positions of the indications appearing on thebaseline andthe
positions of their sources.
'Immersion Testing
b
A technique of testing, using a liquid as an ultrasonic couplant, in which the test part and at least the
transducerface is immersed in the couplant and the transducer is not in contact with the test part.

Impedance (acoustic)
A material characteristicdefined as a product of particle velocity and material density.
Indication(ultrasonics)
The signaldisplayedor read on the ultrasonic systems display.
InitialPulse
The first indicationwhich may appear on the screen. This indication represents the emission of ultrasonic
energy fromthe crystal face (main bang).
Interface
The physical boundary between two adjacent acoustic mediums.
Insonification
Irradiationwith sound.
Isotropy
A condition in which significantmedium properties (velocity, for example) are the same in all directions.
LambWave
A typeof ultrasonic vibration guided by parallel surfaces of thin mediums capableof propagationin
different modes.
Linearity(area)
Asystemresponse in which a linear relationship existsbetween amplitudeof response and the
discontinuity sizesbeing evaluatednecessarilylimited by the size of the ultrasonicbeam. v
Linearity(depth)
A systemresponsewhere a linearrelationship existswith varying depth for a constant size discontinuity.
Longitudinal Wave Velocity
The unit speed of propagation of a longitudinal(compressional)wave through a material.
Loss of Back Reflection
Absence of or a significantreductionof an indication fromthe back surface of the articlebeing inspected.
Maior ScreenDivisions
The vertical graticuleused to divide the CRTinto 10equal horizontal segments.
Manipulator
A deviceused to orient the transducer assembly. As appliedto immersion techniques, it provideseither
angular or normal incidence and fmes the transducer-to-part distance.
MaterialNoise
Extraneoussignals caused by the structure of the materialbeing tested.
Miniature Angle Beam Block
A specifictype of reference standardused primarily for the anglebeam method, but alsoused for straig w
beam and surfacewave tests.
Inspeetor's Handbook

Minor ScreenDivisions
The vertical graticuleused to divide the CRT into fifty equal segments. Each major screen division is
divided into five equal segmentsor minor divisions.
; M o d eConversion
The change of ultrasonicwave propagation upon reflection or refraction at acute angles at an interface.
Mode
The manner in which acoustic energy is propagated through a material ascharacterizedby the particle
motion of the wave.
Multiple Back Reflections
Repetitive indications fromthe back d a c e of the material being examined.
Nanosecond
Onebillionth of a second.
Narrow Banded
A relative term denoting a restricted range of frequency response.
Near Field.
A distance immediatelyinfront of a transducer composedof complex and changingwave front
characteristics.Also known as the Fresnel field.
Node
The point on the examination surfacewhere the V-path begins or ends.
L.
L40ise
Any undesired indications that tend to interferewith tkinterpretationor processinn of the ultrasonic-
information;also referred to as "grass."
Normal Incidence
A condition where the angle of incidence is zero.
Orientation
The angularrelationship of a surface,plane, defect axis, etc., to a referencep l w or sound entry surface.
Penetration(ultrasonic)
Propagationof ultrasonicenergy through an article.
Phased Array
A mosaic of probe elementsin which the timing of the element's excitationcan be individuallv controlled
toproduce certaindesired effects, such as steeringthe beam axis or focusing the beam.
PiezoelectricEffect
The characteristic of certain materialsto generate electrical charges when subjectedto mechanical
vibrations and, converselyto generatemechanical vibrations when subjected to electricalpulses.

Polarized Ceramics
Ceramic materials that are sintered(pressed), created (approximately 100oOc),and polarizedby applying a
direct voltage of a few thousand volts per centimeterof thickness. The polarization is the process that makes these
ceramicspiezoelectric. Includes sodium bismuth titanate, lead metaniobate, and severalmaterialsbased on lea+
zirconatetitanate (PZT). u
Presentation
The method used to showultrasonic information. This may include (among others)A-, R,or C-scans
displayedon various types of recorders, CRTs, LCD's or computerized displays.
Probe
Transducer or searchunit.
Propagation
Advancement of a wave through a medium.
PulseEchoTechnique
An ultrasonictest technique using equipment which transmits a seriesof pulses separatedby a constant
period of time; e., energy is not sent out continuously.
PulseLen*
Time durationof the pulse fromthe searchunit.
PulseRate
For the pulse echotechnique, the number of pulses transmitted in a unit of time (also called pulse repetition
rate).
..r
RadioFrequencyDisplay(RF)
The presentationof unrectifiedsignals in a display.
i.bxs
The maximum ultrasonicpath length that is displayed.
Rarefaction
The thinning out or moving apart of the consistent particles in the propagating medium due to the
relaxation phase of an ultrasonic cycle. Opposite in its effect to compression.The soundwave is composedof
alternatecompressionsand rehctions of the particles in a material.
Raylei& WaveISurface Wave
A wave that travels on or close to the surface and readily follows the curvature of the part being examined.
Reflectionsoccur only at sharpchanges of directionof the surface.
Receiver
The sectionof the ultrasonic instrument that amplifiesthe electronicsignals returning from the test
specimen.Also, the probe that receives the reflected signals.
ReferenceBlocks
A block or seriesof blocks of material containing artificial or actual discontinuitiesof one or more
reflecting areas at one or more distances *om the sound entry surface. These are used for calibratinginstrume
and in defining the size and distance of discontinuous areas in materials.
5-8 Inspector's EI.andbook

Reflection
The characteristicof a surfaceto changethe direction of propagating acousticenergy; the retun of sound
3- -resfrom surfaces.
L
Pehction
A change in the directionand velocity of acousticenergy after ithas passed at an acute angle through an
interfacebetweentwo differentmediums.
RefractiveIndex
The ratio of the velocity of a incident wave to the velocity of the refhcted wave. It is a measure of the
amount a wave will be refracted when it entersthe secondmedium after leavingthe first.
Reiect/Suppression
An instrumentfunction or control used for reducing low amplitude signals. Use of this controlmay affect
vertical linearity.
RepetitionRate
The rate at which the individualpulses of acousticenergy are generated; also Pulse Rate.
Resolving Power
The capabilitymeasurement of an ultrasonic system to separate in time two closely spaceddiscontinuities
or to separate closely spaced,multiple reflections.
Resonance Technique
A technique using the resonance principlefor determining velocity, thickness or presence of laminar
LSiscontinuities.
,iesonance
The conditioninwhich the hquency of a forcing vibration (ultrasonicwave) is the sameas the natural
vibration frequency of the propagationbody (test object), resulting in large amplitude vibrations.
Saturation(scope)
A term used to describe an indicationof such a size as to exceed full screen height (100%).
Scanning(manual and automatic)
The moving of the searchunit or units along a test surfaceto obtaincompletetesting of a material.
Scattering
Dispersionof ultrasonic waves in a medium due to causes other than absorption
SecondLeg
The sound path beginning at the point of contact on the opposite surface and extendingto the point of
contact on the examinationsurface when performing angle beam testing.
Sensitivity
The ability to detect small discontinuitiesat given distances.The level of amplificationat whichthe
receiving circuit in an ultrasonic instrument is set.
Shear Wave
The wave in which the particles of the medium vibrate in a directionperpendicularto the directionof
propagation.
Inspector's Handbook 5-

Signal-to-Noise Ratio (SNR)
The ratio of amplitudes of indicationsfrom he smallest discontinuity considered significantand those
caused by random factors, such as heterogeneity in grain size, etc. ,-
u
Skip Distance
In angle beam tests of plate, pipe, or welds, the linear or surface distancefromthe sound entrypoint to the
firstreflection point on the same surface.
Snell's Law
The law that definesthe relationshipbetween the angle of incidence and the angle of refkction across an
interface, based on a range in ultrasonic velocity.
Specific Acoustic Impedance
A characteristicwhich acts to determine the amount of reflection which occurs at an interface and
represents the wave velocity and the product of the density of the medium in which the wave is propagating.
StraightBeam
An ultrasonicwave traveling normal to the test surface.
Sweep
Theuniform and repeated movement of a spot acrossthe screen of a CRTto formthe baseline.
Through-Transmission
A test technique using two transducersin which the ultrasonic vibrations are ernittedby one and received
by the other, usually on the opposite side of the part. The ratio of the magnitudes of vibrationstransmitted and
received is used as the criterion of soundness. ' 4
Tip Diffiction
Theprocessby which a signal is generatedfrom the tip (i.e., top of a fatigue crack)of a discontinuity
through the interruptionof an incident sound beam propagating through a material.
Transducer (search unit)
An assembly consistingbasically of a housing, piezoelectric element, backing material, wearplate
(optional) and electrical leads for converting electrical impulses into mechanical energy and vice versa.
TransmissionAngle
The incident angle of the transmittedultrasonicbeam. It is zero degrees when the ultrasonicbeam is
perpendicularto the test swface.
Transmitter
The electricalcircuit of an ultrasonic instrument that generatesthe pulses emittedto the searchunit. Also
the probe that emits ultrasonic signals.
Two Probe Method
Use of two transducers for sendingand receiving. May be either send-receive or through transmission.
Ultrasonic Absorption
A dampingof ultrasonic vibrationsthat occurswhen the wave transversesa medium.

Ultrasonic Spectrum
The frequency span of elastic waves greaterthan the highest audible kquency, generallyregarded asbeing
higher than 20,000 hertz, to approximately 1O00megahertz.
'Jltrasonic Svstem
Thetotality of componentsutilized to perform an ultrasonic test on a test article.
V-path
Thevath of the ultrasonic beam in the test object fromthe point of entry on the examination surface to the
back surface'and reflecting to the front surface again.
Velocity
The speed at which sound travelsthrough a medium.
Video Presentation
A CRT presentationin which radio frequency signalsnave been rectified and usually filtered.
Water Path
The distancefnrmthe face of the searchunit to the entry surface of the materialunder test in immersion
testing.
Wavelength
The distance in the direction of propagationfor a wave to go through one completecycle.
Wedgelshoe
A deviceused to adapt a straightbeam probe for use in a specifictypeof testing, including angle beam or
Ld a c e wave tests and tests on curved surfaces.
Wraparound
Nonrelevant indications that appearon the CRT as a result of a shortpulse repetitionrate in the pulser
circuit of the test instrument.

CommonMath Formulas
Wavelength
L
I
T
5-12 Inspectar's Handbook
r ? = Wavelength
V = Veloocity
F = Frequency
ReflectedAcoustic Energy
21-22 ) 2
ER= 100 (-
21+22
ER= Energy reflected
Z1 = Acoustic impedance material#1
22 = Acoustic impedance material#2
Nearfield (nearzone) u
N =
D * (F)
4 (V)
N = Length of the near field
D = Diameter of the transducer
F = Transducer frequency
V = Materials velocity
CrystalThickness
hCT =
2
CT = Crystalthickne$s
h = Wavelength
Use .23 if material is unknown
Energy Transmitted
ET = El -ER
ET = Energytransmitted
El = Energyintiated
ER = Energy reflected
Acoustic Impedance
z = POI)
Z = Acoustic impedance
P = Materialsdensity
V = Acousticvelocity
HalfAngle Beam Spread
vSIN 0 = K ( )
D*F
K= 1.22
V = Velocity of the material
D = Diameterof the transducer
F = Frequencyof the transducer
Times2 forfull anglebeam spread
Decibel Difference
A1
Db=20 [LOG (-)IA2
Db= Decibel difference
LOG= Naturallogrithm
A1= Amplitude number one
A2 = Amplitude number two
Rule ofthumb:every 6 Db doublesthe size of the
indicationheight (pip)
Snell's Law & Angle of Reflection
SIN 01 =
SIN 02 * V1
V2
Angle of incidence * 1stcritical angleV2 is long = 90°
Critical angle* 2nd criticalangleV2 is shear = 90°
Wedge angle
SIN 02 = 'IN * V2
v1

Half / Full Sound Path & Skip / SetbackDistance
T HALF SKIP = T TAN 8
HSP= -COS 0
2T FULL SKIP = 2T * TAN 0
FSP= -cose
T =Memberthickness
Surface Distance to Defect / Depth of Defect
SDD = Sound Path* SIN 8 #DD =Sound Path* COS 8
##DD =(Sound Path* COS 0) - 21
SDDSurface distanceto defect
#DD=Depthof defedduringhalfsound path
##OD =Depthofdefectduringfull sound path
T=Memberthickness
CalibrationChart-UT Shearwave
b
PLATE
THICKNESS *HALF SKIP
1" 112" 314" 1"
PLATE
THICKNESS FULL SKIP
I 1 - 112" 1 -314" 2"
* Applicableholesinthe M.I. blockfor calibration

Velocity Chart
I I I LONGITUDINAL 1 SHEAR I ACOUSTIC 1
Aluminum
Aluminum Oxide
Bertilium
Copper I 8.9 I -18 I .089 I 41.6
CrownGlass 2.5 .21 .I2 18.9
Ice 1.OO .I6 .08 3.5
,Inconel - - - - .22 .I2 47.2
Iron - - - - .23 .I3 45.4
2.7
- - - -
1.82
.43 I - - - - I
,#~&~~~;@~$~g+;~~~~$[@:@~,t
KrTnCarbie I - - - -
Mercurv - - - - .057 I - -- - I 19.6
Molvbdenum 1 10.09 1 .25 .I3 64.2
Cadium 8.6 .ll 1 .059 ! 24
, , ,-,*,.,. $>, . s , , ~v.x<,,,, ..",
~~~&~'i~$&iia$gfigp&+
.25
.39
-51
$~f&<gg$-@@#
lOil (SAE 30) I 0.95 1 .067 I ---- 1.5 I
Monel - - - -
' ,"":G,~w$~.~$s~&-&~.,, ";?$;>$..p$",2$$2
~~~wp&n8:F~w~;&~k~&iyr.~I-j~.t~~...
Nickel I 8.3
.I2
.23
.35
Steel, Mild I 7.7 I .23 I .I3 I 46
,Steel, Stainless I 8.03 1 .23 -12 I 45.4
17
32
23
.21 I -11
~%;62%,:*, "' y , ' ' % ~ ; ~ ~ ~ ~!$%:?>&@&$?& & ,..<::
;&4~;.~~%<~$~&~~i-~f,6"t*~5-i.&i&+&r.
-22 I .12
Polyethylene
Polvstyrene
Polyurethane
47.6
2@&d@@& ' w'*'",*
;>:'. 5~;,%k.a3g&&g$$
49.5
- - - -
1.06
- - - -
Titanium
Tungsten
Uranium
.07
.093
.07
4.54
19.25
- - - -
.02
.04
----
.24
.20
.I3
1.7
2.5
1.9
-12
.I1
.OW
27.3
101
63

Chapter 6 -Eddy Current Testing
Common Terms and Definitions
AbsoluteCoil
b A test arrangementwhich teststhe specimenwithout any comparisonto eitheranotherportion of the test
specimenor to a known reference.
Alternating
A voltage, current or magnetic field that reverses direction at regularly recurring intervals.
Bobbin Coil
A coil or coil assemblyused foreddy current testing by insertion into the test piece; e.g., an inside probe
for tubing. Also referred to as Inside Coil or IP Coil.
Coil-
Conductor wound in one or more loops to produce an axialmagnetic fieldwhen current is passed through
it.
Coil Spacing
The axial distance between two encirclingcoils of a differential system.
Conductivity
/
Thewillingness of a test circuit or test specimento conduct current.
Coupling
A measure of the degree to which the magnetic field of the coil passes through the test specimenand is
w ffkted by the magnetic field created by the flow of eddy currents.
Defed Resolution
A property of a test systemwhich enables the separationof signalsdue to defects in.thetest specimenthat
are located in close proximity to each other.
Diamagnetic
A material having a permeability less than that of a vacuum.
Differential Coil
A test arrangement which tests the specimenby comparing the portion being tested with eitheranother
portion of the same specimenor to a known reference specimen.
Discontinuitv, Artificial
Reference discontinuities, such as holes, grooves, or notches, which are introducedinto a reference
standardto provide accurately reproducible sensitivitylevels for electromagnetic test equipment.
Double Coil
A test arrangement where the alternating current is suppliedthrough one coil while the changein material
conditionis measured from a second coil.
Eddy Current
L A circulating electricalcurrent induced in a conductivematerial by an alternatingmagnetic field.

Edge or End Effect
The disturbance of the magneticfield and eddy currents due to the proximity of an abrupt change in
geometry (edge, end). The effect generally results in the masking of discontinuitieswithin the affected region.
f
Effective Depthof Penetration d
The depth in a material beyond which a test system can no longer detect a changein material properties.
EffectivePermeability
A hypothetical quantity
conductorin an encirclingcoil.
which is used to describethe magnetic field distributionwithin a cylindrical
The field strengthof the applied magnetic field is assumed to be uniform over the
entire cross section of the test specimenwith the effectivepermeability, which is characterized by the conductivity
and diameter of the test specimen and test frequency, assumingvalues between zero and one, suchthat its
associated amplitude is always less than one within the specimen.
ElectromagneticInduction
The process by which a varying or alternatingcurrent (eddy current) is induced into an electrically
conductivetest object by a varying electromagneticfield.
ElectromagneticTesting
That nondestructivetest method for engineeringmaterials, includingmagnetic materials, which uses
electromagnetic energy having frequencies less than those of visible light to yield information regarding the quality
of the tested material.
Encircling Coil
A coil, coils, or coil assemblythat surroundsthe part to be tested. Coils of this type are also referred to as
circumferential, OD or feed-throughcoils.
w
External ReferenceDifferential
A differentialtest arrangement that compares a portion of the test specimento a known reference standard.
Ferromagnetic
A material which, in general, exhibitshysteresisphenomena, and whose permeability is dependent on the
magnetizing force.
Fill Factor
For an inside coil, it is the ratio of the outside diameter of the coil squaredto the inside diameter of the
specimen squared. For an encircling coil, it is the ratio of the outsidediameter of the specimen squaredto the
inside diameter of the coil squared.
Flux Density
A measure of the strength of a magnetic field expressed as a number of flux lines passing through a given
area.
Henry
The unit of inductance. More precisely, a circuit in which an electromotive force of one volt is induced
when the current is changing at a rate of one ampere per second will have an inductanceof one henry. (Symbol: H)
Hertz
The unit of frequency (one cycle per second). (Symbol: Hz)

High Pass Filter
An electroniccircuit designedto block signals of low frequencywhile passing high frequency signals.
IACS
k The International Annealed Copper Standard. A value of conductivity establishedas a standard againstw
which other conductivityvalues are referred to in percent IACS.
Impedance
The ovtmsitionto current flow in a test circuit or a coil due to the resistance of that circuit or coil, plus the
electrical of the coil as affectedby the coil's magnetic field.
Impedance Analysis
An analyticalmethod which consists of correlating changes in the amplitude,phase, or quadrature
components (or all of these) of a complex test signalvoltage to the electromagneticconditionswithin the
specimen.
Impedance-planeDiagram
A graphical representationof the locus of points indicatingthe variations in the impedanceof a test coil as
afunction of basic test parameters.
Inductance
The inertial element of the electriccircuit. An inductor resists any sudden change in the currentflowing
through it.
Inductive Reactance
The opposition to current flow in a test circuit or coil when an alternatingvoltage source is applied and due
solelyto the electricalproperties of the mil as affected by the magnetic field.
b
Inertia
Thepropertyof matter which manifests itself as a resistance to any change in the momentum of a body.
Lift-off
The distancebetween a swfaceprobe coil and the specimen.
Lift-off Effect
The effed observed dueto a change in magnetic couplingbetween a test specimenand aprobe coil
whenever the distance between them is varied.
Low Pass Filter
An electroniccircuit designedto block signals of high frequency while passing low frequency signals.
MagneticField
A condition of space near a magnet or current-carrying wire in which forcescan be detected.
MagneticFluxLines
A closed curve in a magnetic field throughpoints having equal magnetic force and direction.
Noise
Any undesired signalthat tendsto interfere with the normal receptionor processing of a desired signal.. In
haw detection, undesired response to dimensional and physical variables (otherthan flaws) in the test part is called
"partnoise.

Nonferroma.gnetic
A material that is not magnetizable and hence, essentially not affected by magnetic fields. This would
includeparamagnetic materials having a magneticpermeability slightlygreater than that of a vacuum and
approximatelyindependent bf the magnetizing force and diamagneticmaterials having a permeability less tha- ''
of a vacuum. V
Paramagnetic
A material having a permeabilitywhich is slightlygreater than that of a vacuum, and which is
approximatelyindependent of the magnetizing force.
Permeability
A measure of the ease with which the magnetic domains of a material align themselves with an externally
applied magnetic field.
PermeabilityVariations
Magnetic inhomogeneitiesof a material.
Phase Analysis
An instrumentationtechnique which discriminatesbetween variables in the test part by the differentphase
angle changes which these conditionsproduce in the test signal.
Phase Angle
The angle measured degreesthat the current in the test circuit leads or lags the voltage. One complete
cycle is equal to 360".
Phase Shift
A change in the phase relationship between two alternating quantitiesof the same frequency. w
Probe Coil
Asmall coil or coil assemblynormally used for surfaceinspections.
- ReferenceStandard
A test specimenused as a basis for calibrating test equipment or as a comparisonwhen evaluatingtest
results.
Reiection Level
The setting of the signallevel above or below which allparts arerejectable or in an automatic system at
which objectional parts will actuatethe reject mechanism of the system.
Resistance
The opposition to current flow in a test circuit or coil based on specificmaterial properties and cross-
sectionalarea and length of a conductor.
Response Amplitude
The property of the test systemwhereby the amplitudeof the detected signalis measuredwithout regard to
phase.
Saturation
The degree of magnetizationproduced in a ferromagneticmaterial for which the incremental permeabili
has decreased substantially to unity.

Self-comparison Differential
A differentialtest arrangementthat comparestwo portions of the sametest specimen.
Signal-to-noise Ratio
L The ratio of responseor amplitudeof signalsof interestto the response or amplitude of signals containing
no usell information.
SingleCoil
A test arrangement where the alternating current is supplied through the same coil from which the-
indication is taken.
Skin Effect
A phenomenon where, at high frequencies, the eddy current flow is restrictedto a thin layer of the test
specimen close to the coil.
Standard
A referenceused as a basis for comparison or calibration;a concept that has been establishedby authority,
custom, or agreement to serve as a model or d e in the measurement of &tity or the establishment of a practice
or a procedure.
StandardDepth of Penetration
The depth in a test specimenwhere the magnitude of eddy currentflow is equal to 37 percent of the eddy
current flow at the surface.

Two Types of Electrical Current
Direct Current (DC)
4
- Current flowis constant over time
- Current is distributeduniformly over the cross-sectionof the conductor
- Example: battery
Current strength and direction remain constant overtime
Time
AlternatingCurrent (AC)
- Current flow varies over time w
- Current flows at or near the surfaceof the conductor -this phenomenon is called the SL,
effect
- Example: 60 cycle ac in wall sockets
Current strengthvaries over time; current
directionreverses every 112 cycle
Time
Inspector's Handbook'

Conductivityand the IACS
Conductivityof a metal is usually expressed as a percentage (%) and is based on the internationalannealed copper
standard (IACS).
k .
A specificgrade of high purity copper was designatedas 100%conductivity.All other metals (except silver)are
designated some %less then 100%. These percentages indicatethe relative efficienciesof the various metals for
carrying electric current.
Right Hand Rule
L
An easy method for fmding the direction of an electricallyinduced magnetic field is to imagine graspingthe
conductorin the right hand with the thumb pointing in the direction of the current flow. The fingerswill then point
in the direction of the lines of force. This is the right hand rule and is shownbelow. From this figureit can be seen
that the current flow in the conductorcreates circular lines of force.
CURRENT
FLOW
The coil's magnetic field intensity (strength)decreaseswith'in~reasin~distanceaway from the outside of the coil.
C*
The field intensity at point C is less
than at point B, and point B's intensity
C is less than point A's
B
A

C1
The coil's field intensity (strength) is assumed to be constant across the inside
diameter of the coil. This assumption is based on the use of AC and small
diameter coils, and for all practicalpurposes the assumptionis valid. W'
' ./-Y
Lines of
Force
The coil's magnetic field can be viewed as a distributionof lines of
force aroundthe coil. These lines of force are call magnetic flux, and
represent the coil's magnetic force (symbol 'H').
Current Current
in
- 0 -
out
C . - -
-0
I
When a metal rod is placed insidethe coil, the coil fluxpasses through the
rod. The number of lines of force in the rod divided by the cross-sectional 'N
area of the rod equals the flux density (symbol 'B') in the rod. The flux
density in the rod depends on the metal's willingness to cany the magnetic ,'flux. The metal's willingness to carry these magnetic flux lines is called /
permeability. The symbol for permeability is 'p'(mu).
'
N - * ---I- w
Mathematically,permeabilityis expressed as the flux density in the material (B) divided by the magnetizingforce
(H) that caused it.
Permeability
B
= o r p
H
Flux densih
Magnetizing force
Like conductivity,permeability is a material property that is the same for all samples of a particularmaterial
(assume same chemistry, etc.).
example: p,for air = 1
p for copper alloys= 1
p,for steels = severalthousand

The permeability value of 1 for air and copper alloys(and all other nonmagneticmaterials)means that the
magnetic flux in the material is exactly equal to the flux coming from the coil.
b
stated another way: b/h = 1 only when b =h
The high permeability value of steels (and all other ferromagneticmetals) means that the magneticflux inthe
metal is thousands of times greater than the applied flux fiom the coil.
stated another way: b/h =2000 means h,,= 2000 x h,,
Magnetic Domains
Obviously, somethingis happening in the ferromagnetic metals to create all this additional flux that is not
happening in the nonmagnetic materials. Magnetic domainsare groups of atoms within a ferromagneticmetal
which behave like tiny permanent magnets.
In unmagnetized magnetic materials, the domains are randomly oriented
and neutralize each other, producing no observable magnetic flux in the
. metal.
w
When the magnetizing force fiom the coil, is applied, the domains begin
to align in the directionof the appliedflux. Their combined individual
magnetism startsto produce an observable increasein the flux in the
metal, over and above the applied flux (H).
When the domains are completelyaligned, the metal is said to be
saturated, and the flux 'B' is many thousands of times greater than the
applied flux 'HI. This domainbehavior is responsible for the mrrlinear
relationship between (E3) and (H) in ferromagneticmetals and for the
hysteresis effect.
Partially Oriented Domains
Completely Oriented
Domains (saturation)

When a coil of wire carrying alternatingcurrent is brought into proximityto a conductingarticle. The alternating
magnetic field that surroundsthe coil will penetrate the article, generatingsmallcirculatingelectricalcurrents,
called eddy currents, in an article.
Note: When a generator's
electrical current reverses it
direction, the directionof the
eddy currents will ako reverse. I I II Electricalcurrent
$4 Test coil
Article being tested
Eddy currentsare circulating electrical currents induced in an isolated conductor by an alternatingmagneticfield.
Note that there is no direct electrical contactbetween the coil and the test article - eddy currentsare generatedby
electromagnetic induction.
Direction of coil's field
The "primary" magnetic field
surroundingthe ac coil will penetrate
the test articlesand induceeddy
c m t s in the article. The circulating
Ac
eddy currentspossesstheir own
"secondary"magnetic field. This
secondary field will opposethe coils . 1 . I
and reduce the size and strengthof the I , #--*
coil's field.
A Eddy current field
opposes coil's field
Inspector's I F a n h k

Changes in the strengthor shape of the secondaryfield will affectthe primary field, which will affectthe AC
flowing in the coil, where it will be sensed.
LTn this way, variations of the test article that disturb or alter the flow of the eddy currents will disturb the
electromagneticcouplingbetween the two fields and cause indications on the test instnunent
Characteristicsof Eddy Current
1) Can only be induced in conductors
Test circuit
Changes in
conductivity
Coated(i.e. painted)
articlesmay be tested, since the
coils fieldwill pass through the
nonconductingcoating and
&@) oncconductivematerial

generate eddy currentsin the metal e
-Change in coil's
impedance
-------------.----I-------------------Change in coil's
magnetic field
beneath.
Change in
meter reading
Plated articles shouldnot be
tested, since the coil's field will
generate eddy currentsin both the
metallicplating and the base
material. Consequently,ET
indicationscould originate from
either the base metal or the
plating, confusing the inspection.
Material
1--conductive material
*Conductivematerial
-Conductive mate
2) Can be generated onlyby an alternatingmagnetic field -there must be relative motionbetween the field and
the test article. A DC field will not generate eddy currents. The moving AC field which buildsup, then breaks
down and reverses direction every 112 cycle, is essential to the production of eddy currents.
3) Eddy currentsflow
in circularpaths,
parallel to the coil
windings.
/ENCIRCLING COIL
CRACK
EDDY
CURRENTS

Depth of Penetration
Eddy currentsare strongest at the surface nearest the coil (dueto skin effect) and weaken with depth. The depth of
eddy current penetration below the surface is directlyaffkctedby the nearness of the coil to the test article, the
operating frequency, and the test article conductivityand permeability.
I 4
(A) Coilposition - sincethe coil's field is limited in size and decreasesin strength with increasingdistance away
fromthe coil, maximum field penetrationinto the article and, therefore, maximum depth of eddy current
penetration is achieved by mving the coil as close aspractical to the test article surface.
02, /='
I I
1 + ' 8
coil far away 71
fromarticle 1 I-being tested
possible to the
articlebeing
tested
(B) Operatingfrequency -a relationship alsoexistsbetween the frequencyof the ac appliesto the test coil and the
eddy current depth of penetration. As the frequency is increased, eddy current distributionconcentrates near
the surfaceand decreasesdeep with the test article. The reverse is alsotrue. As the frequency is lowered,the
eddy currentdistribution extends deeperintothe article.
Depthof
Penetration
I I
View A
Frequency
-
Depthof
Eddy Current
Penetration
View B
In both view A and B above, the material and the test coil are the same. Sinceview a shows deeper eddy current
penetration into the material, this means that a lower frequency was used. View B shows shallowerpenetration, so
a high frequencywas used. Keep in mind that a high frequency causes the eddy currentsto accumulatenear the
surface closest to the test coil.

c) Conductivity-the figurebelow illustratesthat the depth of eddy currentpenetration also varies with metal's
electricalconductivity.As conductivity increases,the depth of eddy currents decreases.
In the figure, the coil and test frequencyare the same in each view. Only the materialtypeis different. You can
verifl that tin is more conductive the lead, and that copper is much more conductive thaneither, by referringto the
% IACS conductivitychart shown earlier. As the figure shows,the less conductive metals achieve deepereddy
current penetrationthan the more conductivemetals.
'c/
Indicator Indicator Indicator
oil Coil oil
d) Magneticpermeability -f d y , a metal's magnetic permeability (p) affectsthe depth of eddy current
penetration. The depth of penetration decreaseas the permeabilityincreases. There are 3 basic types of eddy
current test: surface ,encircling,and inside.
A surfacecoil is designed to be used on localized areas on a surface, and is usually containedin a hand-heldprobe.
'L
Depthof
Eddy
Current
Penetration
An encirclingcoil, on the other hand, is large enough to surroundan object about oneof its axes and is designed to
test an entire segment of the object at onetime.
2
.'.::..::.'.:::.:;:.::..::-.:::.::.::............:.:::.,::::: :.:
Depthof -Eddy
Current
Penetration
Lead Tin copper

Encircling Coil
An inside coil is designedto be placed inside a hole or cavity in the object, and is especiallysuited fortestingthin
wall tubing.
ARTICLE
b b $ L c
--,co,L
INSIDE COIL
Note that with eachof the coil types:
- The eddy currentscirculateparallel to the coil windings
- The eddy currentshug the surface that is nearest the coil

Each of these 3 coil types may be used in eitherthe differential or absolutetest mode.
In the differentialcoil arrangement,two side-by-side coils arewound and connected sothat the outputof on
cancelsthe output of the other as long asthe test object properties are the sameunder both coils. Thismode is most
ensitive to small defects and is relatively insensitiveto material variations such as hardness, gross surface
megularities, etc.
P1
DIFFEREN T l A L
In the absolutemode, a singlecoiltests the area of the test object beneath it without comparisonto a reference
area This mode is most sensitiveto large defects longer than the coil, and to material variations such as hardness,
gross surfaceirregularities, etc.
ABSOLUTE COIL
The 3 generalmaterial variables (properties) that affect the flow of eddy currentsin the material are:
1) Changes in conductivity- conductivitychanges may be causedby variations in alloy chemistry orheat
treatment, or may be dueto the presence of defects. Sincecracks or other discontinuitiesforcethe eddy
currentsto take a longerpath by flowing around them, the overall effect of the discontinuity is to reducethe
conductivity of the metal.
TEST COI L
EDDY CURRENT MAGNETIC FIELD
MAGNETIC FIELD ,TEST COIL
EDDY CURRENT MAGNETIC FIELD
CRACKEDDY CURRENT

As the figure illustrates,the eddy currentsmust flowaroundthe crack, effectivelyreducingthe conductivity of the
metal.
2) The secondmaterial variable affectingeddy current flow is magneticpermeability. Eddy currents are induf '
by fluxchanges in the metal and are directlyrelated to the density or amount of flux.Sincechangesin ' 4
permeability cause changes in the amount of flux in the metal, they also cause a pronounced (and detectable)
change in the eddy current flow.
3) Changes in the physical dimensions, or size and shape of the test object also affectthe eddy current flow.
Although the figurebelow is a gross example, it clearly illustrates how a change in physical dimensioncan
alter the electromagneticcouplingbetween the coil and the object.
Twomore dimensional of eddy current testing is edge effect and lift-off.
Edge effedis the falseindicationcausedby disruption of by disruptionof the eddy current path when the coil
approachesan end or edge of the material.
w
The effect is strong enough to "mask' any changes due to other factors. In effect, the edge of the material looks h e
a very large crackto the eddy current instrument.
Onthe other hand, the false indication caused by changingthe spacingbetween the test coil and the material
d a c e is called lift-off.
-------------'
MAGNETIC

Lift-off has a very large effect on the ET output displaydueto the decrease in primary field fluxin the material as
the coil distance fromthe materials surface is increased.
The lift-off effect canbe used to measurethe thickness of nonconducting coatings, such as paint, on a conducting
object.
WONCONDUC
SURFACE
I
1 CvnOUCTlVE MATERIAL
IIARTICLE
b
A c e eddy currents cannotbe generated in the nonconductor, a coil placed in contact with the painted surface
"sees"the paint thickness simplyas lift-off distance.
Another important relationshipbetween eddy current flow andthe presence of discontinuitiesis that the
discontinuity must lieperpendicularto the direction of eddy current flow to be detected.

INSPECTION COIL
EDDY CURRENTS
' SURFACE CRACK
SUBSURFACE
LAMINAR SEPARATION
In the situationabove, a surface coil passes over a surfacecrack and a subsurfacelamination in the metal. It is easy
to seethatthe crack will force the eddy currentsto take a longerpath around it, causing a detectable disruption in
-their flow. The lamination on the other hand, will not cause much disruption of the eddy current path sincethe
. netal separationliesparallelto the directionof current flow.

Limitations of Eddy Current Testing
1. Inspect only conductingarticles(i.e. metals).
2. Can locate only d a c e and shallowsubsurface discontinuities; inspectiondepth is limited to less then 1ii.
3. Separationof the effects of conductivity,permeability,and dimension variables is difficult and oftennot
possible.
4. ET is an indirect inspectionrequiringthe use of calibration standards; you must know what you are looking for
in order to find it.
Advantages of Eddy Current Testing
1. Able to inspectthrough nonconductivecoatings(i.e. paint).
2. Fast, real-time inspection.
3. Totally nondestructive;no interferencewith the test item.
Summary of Properties of Eddy Currents
1. Generatedby an alternatingmagnetic field.
2. Flow only in conductors. 4
3. Circulatesparallel to coil windings.
4. Eddy current flow is affected by changes in the material's conductivity, dimension, magnetic permeability.
5. Limitedto surface/shallowsubdace testing.
6. Depth of penetrationis affected by conductivity and permeability of test object, by test frequency,andby
nearness of the coil to the test object.
7. Able to test through surface coatings (nonconducting)but not through plating (metal).
Eddy Current Relationship of Properties
Penetration
Decrease
Increase
Frequency
Increase
Decrease
Conductivity
Increase
Decrease
Permeability
Increase
Decrease

Chapter 7 - RadiographicInspection
CommonDefinitions and Examples
wAbsorbed dose
The amount of energy imparted to matter by an ionizingparticle per unit mass of irradiated material at the
place of interest. It is expressed in "'rads."
Accelerator
A device that accelerates charged atomicparticlesto high energies. An x-ray machine is an accelerator.
Activity
A measure of how radioactive a particularradioisotopeis. The number of atomsdecayingper unit of time
calculates activation. Its unit of measurement is the "curie."
Alpha particle
A positively chargedparticle emittedby certain radioactivematerials. It is made up of two neutrons and
two protons; hence it is identicalwith the nucleus of a helium atom.
Alpha ray
A stream of fast-moving helium nuclei (alpha particles). This radiation is strongly ionizing with very weak
penetration.
An~strom
A unit of lengthused to express wavelength. One angstrom equals lo-*centimeters.
-Q. W e (target side)
The positiveterminal of an x-ray tube.It is a high melting point element that receives the electron
bombardment fromthe cathode (filament).
Atom
The smallestpart of an element. The atom consists of a nucleus composed,with the exception of hydrogen,
of a number of protons and neutrons. Included in the atom is an extranuclearportion composed of electrons equal
in number to the protons in the nucleus. The hydrogen atom includes a nucleus of one proton and extranuclear
portion of one electron.
Autotransformer
A specialtypeof transformer in which the output voltage can be easily varied. The autotransformeris
employedto adjust the primary voltage appliedto the step-up transformer that produces the high voltage applied to
the x-ray tube.
Background radiation
The radiation of man's radiationnatural environment, consistingof radiationthat comes from cosmicrays
and from the naturally radioactiveelements of the earth, includingradiationfrom within man's body. The term
may alsomean radiation extraneousto an experiment.
Backscatter
Radiation scattered h m the floor, walls, equipment, and other items in the area of a radiation source.
Sackscatterincludes secondaryradiation resulting from the interaction between the primary radiationfromthe
, ' source and the materialbeing radiated.

Beta particle
An electron or position emitted from a nucleus during radioactivedecay.
Bremsstrahlung
~lectroka~neticradiation (photon) emittedby chargedparticles when they are slowed downby e l e d L-
fields in their passage through matter. Literally means, "braking radiation" in German.
200 Kev Electron Leaving
400 Kev Electron 8
200 Kev X-Ray
A lightproof container, which may or may not contain intensifying andlor filter screens, that is used for
holding the radiographic filmsin position during the radiographic exposure.
Cathode (filament side)
The negatively-biased electrode of the x-ray tube. 's/
A deviceused to surround a radiation source and so constructedasto both minimizethe scatteredradiation
and to direct the primary or useful radiation into a more or less parallelbeam onto a localized area.
ComptonEffect
The glancing collision of an x-ray or gamma ray with an electron to an orbitalelectron in matterwith a
lower enxgy in matter with a lower energyphoton scatteredat an angle to the originalphoton path. The electron
does not absorb all of the energy.
Highenergy
Photon de-.0e
Ejected electron
/
/ Photon
/@-o-.1
continues with
4 -
e'L-- '
less energy
' I

I .

Contrast (film)
The change in density recorded on the film that results froma given change in radiationinput. Contrast is
determined h t h e slope of the characteristiccurve.
Tontrast (radiographic)
L
The measure of difference in the film blackeningresulting from various x-ray intensities transmitted
through the object and recorded as density differences in the image. Thus, difference in film blackening from one
area to another is contrast.
Contrast (subiect]
The ratio of radiation intensitiespassing through selectedportions of a specimen.
Definition
The measure of sharpnessin the outline of the image of an object recorded on film,the sharpness is the
functionof the types of screens, exposuregeometry,radiation energy and film characteristic.
Densitometer
An instrument utilizingthe photoelectricprincipleto determine the degree of darkeningof developed
photographic film.
Developer
A chemical solutionthat reduces exposed silverhalide crystalsto metallic silver.
Dose-
The amount of ionizing radiation energy absorbed per unit mass of irradiated materialat a specificlocation,
suchas a part of the human body.
'Y Dose rate
The radiation dose deliveredper unit time and measured, for instance,in rems per hour.
Dosimeter
A device that measuresradiation dose, such as a film badge or ionization chamber.
Duty cvcle
Usually expressed in a percentage to represent the time used versus the time not used.
Electromametic Spectrum
Represents the electromagneticwaves of differentwave lengths. The lines arenot definie boundaries but
ratherphase into one another.
DECREASING -WAVELENGTH -INCREASING
INCREASING -FREQUENCY -DECREASING
X-RAYS
AND
GAMMA
RAYS
L INCREASING -ENERGY -DECREASING
ULTRAVIOLET
RAYS
LIGHT
RAYS
INFRARED
RAYS
RADAR
SHORT
WAVE
RADIO
LONG
WAVE
RADIO

Electron volt
Is an amount of energy equal to the energy gained by one electronwhen it is acceleratedby onevolt.
Emulsion
A gelatin and silverbromide crystal mixture coated onto a transparent filmbase.
Encapsulation
The process of sealingradioactive materialsto prevent contamination.
Filament
A piece of wire in the cathode side, negative side, of the x-ray tube used to produce electronswhen heated.
Specialized filmused for radiographic purposes. The componentsof the film aretwo protectivelayers, two
emulsionlayers, and one acetatebase layer.
acetate protective, . . . . . . . . . . . . . . . . . . . . . . .
base t layers
Filmbad~e
A package of photographicfilm worn as a badge by workers in the nuclear industryto measure exposureto
ionizationradiation. The absorbeddose can be calculatedby the degree of film darkening caused by the irradiation.
Filter
A layer of absorptivematerial that is placed in the beam of radiation for the purpose of absorbing rays, .d
certain wavelengthsandthus controllingthe quality of the radiograph.
Fixer-
A chemical solutionthat dissolvesunexposed silverhalide crystalsfrom developedfilm emulsions.
Fon
A darkeningof the film resulting from chemical actionof the developer, aging, scatteredor secondary
radiation,pre-exposure to radiation, or exposure to visible light.
Geiger counter
A radiation detection and measuring instrument. It contains a gas-filledtube that dischargeselectrically
when ionizing radiation passes through it. Discharges are counted to measure the radiation's intensity.
Graininess
A film characteristicthat consistsof the grouping or clumpingtogether of the countless small silver grains
into relatively large masses visible to the naked eye or with slight magnification.
Half-life
The time in which half the atoms in a radioactive substance decay. Time is dependant upon the element.
Half-life (biological)
The time requiredfor a biological system, such as a man or an animal, to eliminate, by naturalprocessr _c
half the amountof a substancethat has entered it.

Hal6value layer
The thickness of a material required to absorb one half of the impinging radiation.
F
Intensifyingscreen
A layer of materialplaced in contact with the film to increase the effect of the radiation, thereby shortening
'v
he exposure.
Interlock
A device for precluding access to an area of radiationhazard eitherby preventingentry or by automatically
removing the hazard.
Ion-
A charged atom or molecularly-boundgroup of atoms; sometimesalso a free electron or othercharged
subatomicparticles.
Ionpairs
A positive ion and a negative ion, or electron,having charges of the same magnitude and formed from a
neutral atom or molecule by the action of radiation or by any other agency that suppliesenergy.
Ionization
The process of adding electronsto, or knocking electronsfrom, atomsormolecules thereby creating ions.
High tempe~tures,ele~tricaldischar~es,and nuclear radiation can cause ionization.
Ionizationchamber
An instrumentthat detects and measures ionizingradiationby observingthe electricalcurrentcreated when
radiation ionizes gas in the chambermaking the gas a conductor of electricity.
,onizing radiation
Any radiation that directly or indirectly displaceselectronsfromthe orbital shellsof atoms.
&v
The energy of X-rays or gamma rays measured in thousand electronvolts.
Latent image
The potential image that is stored in the form of chemical changes in the film emulsion and isbrought out
by developmentof the film.
Latitude
Latitudemost closely alignedwith contrast is commonlycalled the scaleof the film. Latitude is the range
of thickness of materialthatcanbe transferred or recorded on the radiographwithin the usell reading range of
film density. A high contrast film has little latitude and conversely a low contrast film has great latitude.
Leak test
A test on sealed sourcesto assurethat radioactive material is not being released.
Licensed material
Sourcematerial, special nuclear material, or by-product material received, possessed, used, ortransferred
under a general or speciailicenseissued by theNuclear Regulatory Commission.

Mev-
The energy of X-rays or gamma rays measured in million electron volts.
Microshrinkage
Cracks that appear as dark feathery streaks,or irregularpatches, that indicate cavities in the grain w
boundaries.
Monochromatic radiation
A rare condition, hypothetical, in which all gamma rays oi x-rays producedare of the samewavelength.
Pair production
The transformationof a high-energy ray intopair of particles (an electron and a positron) during its passage
through matter.
Particle
A minute constituentof matter with a measurable mass, such as a neutron, proton, or meson.
Penetrameter
A small stripof material of the same
composition as the specimen being tested. Its thickness
T =thickness
4TDIA T DIA 2TDIA
I k I
represents a percentage of the specimenthickness. I
When placed in the path of the rays, its image on the
radiographprovides a check on the radiographictechnique
employed.
Penumbra
The shadow cast when the incident radiation is partly, but not wholly, cut off by an interveningbody; t -space of partial illuminationbetween the umbra, or perfect shadow, on all sides and the fidl light.
Photoelectric effect
Thisprocess involves the completeabsorptionof the photon duringthe process of knockinganelectronout
of orbit. It occurs primarily with lower energy X-rays photons of 10Kevto 500Kev.
Approaching Photon
....a
/e Ejected electron
(negative ion)
Photon absorbed
0 @
/
4-.
/
/ g4-'. '
/
'
I

'
'.--0

,'
/
'Chargedatom
--e4' (positiveatom)
Photon 4
A discretequantity of electromagneticenergy. Photons have no momentum but no mass or electrical
charge.

Positron
A hdamental atomic particle having a mass equal to that of the electron and possessing a positive charge
equal to the negative charge of the electron.
<
'VRoentaen
A unit of exposure dose of ionizingradiation. It is that amount of gamma or x-rays required to produce ions
carrying 1electmst&icunit of electricalcharge in one cubic centimeterof dry airunder standardconditions.
Safelight
A speciallamp used in the darkroomto provide working visibilitywithout affectingthe photosensitive
emulsion of the radiographic film.
Scatter
Secondaryradiation that is emitted in all directions.
Screens
Metallic or fluorescent sheetsused to intensify the radiation effects on films.
Sensitivity
A term usually referring to the ability of the radiographic procedureto detect discontinuities.
Specific activity
Total radioactivity of a given isotope per gram of element.
Source-film-distance
The distancebetween the focal spot of an x-ray tube or radiation sourceand the film, generallyexpressed
.n inches.
Tar~et
Thepiece of material, usually tungsten, embeddedin the anode side, positive side, of the x-ray tube.A
effective and efficienttarget has the following four properties high atomicnumber, high melting point, high
thermal conductivity,and low vapor pressure.
Two-filmtechnique
A procedure whereintwo filmsof differentrelative speedsare used simultaneouslyto radiographboth the
thick and the thin sectionsof an item.

Structure of the Atom and an Element
$ Proton -A heavy atomicparticle with a positive charge.
0 Neutron -Close to the sameweight and sizeof the proton with a neutral charge.
Electron-A negative charged particle weighing about 111840'~of a proton or a neutron.
Nucleus-The proton(s) and ~utron(s)are group here in the centerof the atom.
Atomicnumber "Z"-This number represents the number of protons in the atom.
Mass number "A" -This number represent the number of protons and neutrons in the atom.
fi Helium Atom
E = element symbol
Z = atomicnumber
A = mass number
Componentsof an Isotope
Isotope-One or more of the same elementhaving the same number of protons but not the same numberof
neutrons.
Natural isotopes-Those that occur naturally. v/
Artificial isotope-Those elementsthat are createdby bombardingwith swarms of neutrons.
Activation-This is the process of creatingartificialisotopes.
Stable isotopes-Atoms that are not radioactive.
Unstable isotopes-Atoms that are radioactive.
Characteristics of A RadioactiveElement
During the decay or disintegrationprocess tiny particles of energy are emitted in the form of particles and
waves h m the nucleus.
Alpha particles (a)-The biggest and heaviest of the radiationparticles and is composedof two protons andtwo
neutrons.
Beta particles (13) -A very light particle, actually a high-speed electron.
Gamma rays (?)-A form of energy that is a wave not a particle.
Two Types of Radiation
Gammaradiation-A product of nuclear disintegration or decay of radioactiveelements.
X-rays -An artificialproduced wave from a high voltage electron tube.
1) Soft x-rays -low energy.
2) Hard x-rays -high energy.

History of Radiography
X-rays were discoveredin 1895by Wilhelm Conrad Roentgen (1845-1923)
who was a Professor at Wuerzbug University in Germany. Workingwith a cathode-
--aytube in his laboratory, Roentgen observed a fluorescentglow of crystals on a
table near his tube. The tubethat Roentgen was working with consisted of a glass
envelope (bulb) with electrically positive and negative electrodes encapsulatedin it.
Thetube was evacuated of air, and when a high voltage was applied to it, the tube
would produce a fluorescent glow. Roentgen shielded the tube with heavy black
paper, and found that a green colored fluorescentlight could be seen from a screen
settinga few feet away fromthe tube. He concluded that a new type of ray emitted
fromthe tube. This ray was capable of passing through the heavy paper covering. He
also found that the new ray would pass through most substances casting shadowsof
solid objects. In his discovery, Roentgen found that the ray would pass through the
tissue of humans leaving the bones and metals visible. One of Roentgen's first
experimentslate in 1895was a film of his wife, Bertha's hand with a ring on.
However, it can be argued that the fkst use of X-rays was for an industrial (not
medical) application as Roentgenproduced a radiograph of a set of weights in a box to show his colleagues.
Roentgen's discoverywas a scientificbombshell, and was receivedwith
extraordinary interest by both scientistand laymen. Scientistseverywherecould
,duplicatehis experimentbecausethe cathodetube was very well known during this
period. Many scientist dropped other lines of research to pursue the mysteriousrays,
and the newspapers and magazines of the dayprovided the public with numerous
stories, some true, othersfanciful, about the properties of the newly discovered rays.
Thepublic fancy was caught by the invisibleray with the abilityto pass through solid
matter, and, in conjunction with a photographic plate, provide a picture, albeita
shadowydiffuse one, of the bones and interiorof the body. Scientificfancy was
captured by an extraordinarynew radiation, of shorter wavelengththanlight, that
presaged new and great vistas in physics, and the structureof matter. Both the
scientistand the public were enthusiasticabout potential applications of the newly
discovered rays as an aid in medicine and surgery. Thus,within a month after the
announcement of the discovery, severalmedical radiographs had been made &Europe and the United Statesthat
were used by surgeonsto guide them in their work. In June 1896,only 6 months after Roentgen announcedhis
discovery, X-rays were being used by battlefield physiciansto- -
locatebullets in wounded soldiers.
Prior to 1912,X-rays were used little outside the realms
of medicine, and dentistry, though some X-ray pictures of metals
were produced. The main reason that were not used in industrial
application before this date was because the X-ray tubes (the
source of the X-rays) of that period broke down under the
voltages required to produce rays of satisfactorypenetrating
power for industrial purpose. However, that changed in 1913
when the high vacuum X-ray tubes designed by Coolidge
became available. The high vacuum tubes were an intense and
reliable X-ray sources, operating at energies up to 100,000volts. In 1922,industrialradiographytook another step
forwardwith the advent of the 200,000-volt X-ray tube that allowd radiographsof three inches thick steel parts to
be produced in a reasonable amount of time. In 1931,General Electric Company developed 1000,000volt X-ray
L/ qenerators. That sameyear, the American Society of Mechanical Engineers (ASME) permitted X-rayapprovalof
fusion welded pressure vessels.

gatherin
types of
:--.--+: -
certain I
fluoresc
Shortly afterthe discovery of X-rays, anotherform of penetratingrays was discovered. In 1896,French
scientistHenri Becquerel discovered radioactivity somewhatby accident, like many other great scientific
discoveries. Many of the scientistsof the period were workingwith cathode rays, and other scientistswere
~gevidenceon the theory that the atom couldbe subdivided. Some of this new evidence showedthat cer'qi-
/
'atoms disintegrateby thernselves. It was Henri Becquerel who discoveredthis phenomenon while d
ulvcar~~atingthe properties of fluorescentminerals. Becquerel was working on the principles of fluorescence,
minerals glow (fluoresce) when exposed to sunlight. He utilized photographic plates to record this
:ence.
I
expose-
A
questior
the fog
- - - .- -...
led whal
*g was
. - - . ...
One of the minerals Becquerelworked with was a uranium compound. On a day when it was too cloudy to
his samples to direct sunlight, Becquerel stored some of the compound in a drawer with photographic
dates. When he developedthese plates a couple of days later, he discovered that they were fogged. Becquerel
t would have caused this fogging. He knew he had wrapped the plates tightly before using them, so-
not due to stray light. In addition,he noticed that only the plates that were in the drawer with the
umuum compoundwere fogged. Becquerel concluded that the uranium compound gave off a type of radiation that
could penetrate heavy paper and affectphotographic film.Becquerel continued to test many samplesof uranium
compoundsand determinedthat the source of radiationwas the elementuranium. At this time, enoughinformation
was gathered to determinethat an element, which gives off radiation, is said to be radioactive,and possessesthe
property of radioactivity.Becquerel's discovery was, unlike that of the X-rays, virtuallyunnoted by the layman and
scientist alike. Only a relatively few scientist were interested in Becquerel's findings, and it was not until the
discovery of radium by the Curiestwo years later that interestin radioactivitybecame wide spread.
While working in France at the time of Becquerel's discovery,Polish scientist Marie Curiebecame very
interestedin his work. Shetoo, suspectedthat a uranium ore known as pitchblende containedotherradioactive
elements. Marie and her husband, a French scientist, Pierre Curie started looking for these other elements. In 1898,
the Curies discoveredanother radioactiveelement in pitchblende; they named it 'polonium' in honor of Marie
Curie's native homeland. Later that same year, the Curie's discoveredanotherradioactive element for which the*-
named 'radium', or shiningelement. Bothpolonium and radium are more radioactivethanuranium. Sincethes~ -discoveries,many other radioactive elementshave been discovered or produced.
The initial gamma ray source was radium,which allows radiography ofcastings up to 10to 12inchesthick
During World War 11, industrialradiography grew tremendouslyas part of the Navy's shipbuildingprogram.
Shortlyafterthe war, manmade gamma ray sources such as cobalt and iridiumbecame availablein 1946.These
new sourceswere far strongerthan radium sources and were less expensive. Thusthe manmade sourcesrapidly
replaced radium, and the use of gamma rays grew quickly in industrialradiography.

60" Coverage for Pipes and Location Marker Measurements
I General Information I DistanceBetweenLocation Markers(centerline) 1
Outside Circumference
k.4.
I
Outside Circumference 60"
L~NPS Diameter (ODtimes pi) Coverage
125 I 17 96 8 10

Common Math Formulas
Ii(D1) = 12(D2) 2
Ma, (SFD ,) 2
-Ma, -
(SFD 1
2
2
Ma, (SFD 2 ) 2
-Ma -
(SFD )
1
Ma=MilliamperageSFD=Sourceto film distance
J",:'","
SFD ,,=
a, (SFD 1 ) 2
a,=
2
(SFD )
SFD ,
a ,(SFD )
a 2
(SFD )
1
Ci=Curie SFD=Sourceto film distance

2
Ef, (SFD ,Ef, =
2
(SFD )
Ef (SFD 2 ) '
Ef, =
(SFD )
Ef=Exposurefactor SFD=Sourceto film distance
SFD ;i'T 2 (SFD 1 ) 2
1
- T 1 (SFD 2 ) 2
SFD
T 2 -
(SFD )
1
T=Time SFD=Sourceto film distance
OF, (SFD )
OF, =
(SFD )
2
2
SFD ;i'OF (SFD 2 )
OF 2
OF (SFD ) '
OF, =
(SFD )
1
OF=OffsetSFD=Source to film distance

(TS + GAP) x OM SFD = new SFD
TS
TS=Dependson technique used 7
SFD=Sourceto film distance
GAP=Filmto specimen distance
Dm( Efi) = Dm( Efl)
Dn=Densitv Ef=Ex~osurefactor
(TM or TS) X DS
MS
TM)=Thickness(TM if locationmarker is on TM) -
DS=Defectshift
MS=Markershift
FSS = IS -(2 X PHs)
FSS=Focalspot size IS=lmage size
PHS=Pin hole size
Adding/ Removing
Shielding
I = Intensityafter addingshielding
10 = Originalintensity
HVL = # of Half-value layers added
Determining ShieldingRequired
h (A)
HVL = I
.693
HVL =# of HVCs requiredto reduceintensity
In = Naturallogrithm
lo= Original intensity
I= Desiredintensity
Decay Fomula
A = New activity
Ao = Original knownactivity
n =TlHL
T =Time passed since known activity passed
HL = Half-life of the isotope
I = Intensityafter removingshielding
10 = Originalintensity
HVL = # of Half-value layers added
-
CommonHalf-ValueLayers for IRl92
d
Concrete 1.75"
Steel .500"
Lead .190"
Tungsten .130"
Kodak Radiographic Films
Type Speed Grain
R 8 Ultra fine
M 4 Extra fine
T 2 Extra fine
AA 1 Fine
GammaRadiationExposureCalculator
ExperiencedBased RoentgenFactors (Steel)
D E N S I T Y
F 1.0
.652
1.3
2.6
I
L
M
AA
T
M
1.5
.730
1.46
2.92
2.5
1.25
2.5
5.5
2.0
1.0
2.0
4.0
3.0
1.55
3.1
6.2
4.0
2.4
4.8
9.6

Magic Circles
D=Dose
DR=Doserate
T=Time
Ef-Exposure factor
Ma=Milliamperage
T=Time
EeExposure factor
Ci=Curie
L
T=Time
SingleWall Exposure1 Single Wall Viewing for Plate
I SWE 1 SWV (PLATE)
1
Film
Pb "B"
TM = DESIGN MATERIAL THICKNESS
PENNY = BASED ON Tm
SHIM = BASED ON (1) WELD AND (1) ROOT
REINFORCEMENT
SFD = BASED ON Ts
ENERGY = BASED ON Ts
Inspector's Handbook 7-15.

SingleWall Exposure 1SingleWall Viewing for Pipe
I SWE ISWV (PIPE) 1
Source
*
Film
Pb "6"
PENNY = BASED ON Tm
SHlM = BASED ON (1) WELD AND (1) ROOT
REINFORCEMENT
SFD = BASED ON Ts
ENERGY = BASED ON Ts
Double Wall Exposure1Double Wall View (superimposed)
I DWE 1 DWV
I
Source
*
Film IPb "B"
PENNY = BASED ON (2) Tm
REINFORCEMENT
SFD = BASED ON OUTSIDE OD
ENERGY = BASED ON (2) Tm, (2) WELD AND
I*
(2) ROOT REINFORCEMENTS I

DoubleWall Exposure/ Double Wall View (offset)
I DWE I DWV I
Source +%
-T m
F
Consumable lnsert
I markers I
I Film
I Pb "B"
PENNY = BASED ON (2) Tm
REINFORCEMENT
SFD = BASED ON OUTSIDE OD
ENERGY = BASED ON (2) Tm, (1) WELD AND
(1) ROOT REINFORCEMENT
-
Double Wall Exposure/ SingleWall View
DWE I SWV
I Consumable Insert
I
Film
Pb "B"
PENNY = BASED ON (1) Tm FILM SIDE PENNY CHART
SHlM = BASED ON ( I ) WELD AND (1) ROOT
REINFORCEMENT
SFD = BASED ON (1) Ts
u ENERGY = BASED ON (2) Tm, (1) WELD AND
(1) ROOT REINFORCEMENT
Inspectds Handbook

KILLER CARL
Magnesium
Aluminum
Penetrameter Material and GroupNumbers
Titianium .?1GROUP01 S-51.S-52,s-53
Carbon steel
Alloy steel
Stainless steel
Manganesse-nickel-aluminumbronze S-I 1C. S-11D. S-36B, S-37A.
Aluminum bronze 1 1 . jGROUP 2
S-35, S-36
Nickel-chromium-
iron alloy V~GR3 S-42, S-43. S-44
Nickel-copper alloys
Copper-nickel alloys
Tin bronze
Gun metals
Valve bronze
Inspector's Eandbook

2% Penetrameter Quality Conversion Chart (X-RAY ONLY)

Basic Components of an Xray Tube
Highvoltage
Cathode Struc Power supply
Low- I ' / Filament 87 I/ ,Electron
supply
Focusing
cup
voltage
power 7
Tube
1 envelopeX-ray beam
Types of Scatter Radiation
Test piece
L (a)Internal -(b) Side -(c) Back
scatter scatter scatter

Radiographic Film Interpretation
Arc strikes
DEFINITION: 4
Any localized heat-affectedzone or change in the contour of the surface of the furishedweld or adjacent
base metal resulting from.anarc or heat generated by the passage of electrical energy between the surface of the
finishedweld, base material and a current source, suchas welding electrodes or magneticparticle inspection
electrodes.
RADIOGRAPHIC APPEARANCE:
A localized area, rounded or irregular, and generally found adjacent to the edgeof the weld image on the
base metal. The density of the indication appears lighterwhen the discontinuityis convex fromthe additionof
filler metal with arc strikes resulting from SMAW process. The density of the indication appears darker when the
discontinuity is concave resulting from a gougingof the material with arc strikes resulting fromthe GTAW or
SMAWprocesses.
CAUSES:
Not initiatingthe arc as required by the welding procedure.
Accidentally strikingan arc on the completedweld or base material.
Engaging the magnetizing current prior to establishingfmcontact with the test surfacewhen using prods.
Moving or removingthe prods from the test surface without disengagingthe magnetizingcurrent.
REMARKS/SPECIALCONSIDERATIONS:
Arc strikesfrom welding and MT are generally revealed and dispositionedupon acceptanceVisual inspection.
However, welding arc strikes may occur from anotherwelding operation in the area afterthe VTPT inspectior
and prior to the RT. Arc strikesoccurring in this sequencehave a random location and can be found on the we. Y
well as on the base metal.
Arc strikes fiomMTwill be difficultto detect by RT.
Visual inspectionshould alwaysbe performed to confirm arc strikes.

Burnthrough
DEFINITION:
A. void or open hole extendinginto a backing ring or strip, fusedA
oot or acliacentb&e metal.
- -
IXAULWKAYHICAPPEARANCE:
mirregular localized area of darker density,often rounded,
gmerdlly found at the center of the weld image. If excessiveglobules of
the weld puddle resulting from the burn through, are present on the
inside of the weld joint, their appearancewill have a lighter densitydue
to the additionalweld metal. The nature of burn through is such that the
Using
'Improy- - .
sedges
u.
a weld c
jerly pre
too slou
Idle.
- -- C L ---
of the in i may or may not be sharply defined.
:urrent h
paring t
.
CAUSE;
igherthan allowed by the welding procedure.
t he tungsten electrodetip.
Using r a weldp d of travel will cause overheatingof the
weld put
Improper nr up of the welajomt (unacceptableroot gap).
ECIAL ( IERATIONS:
-I 11G u ~ s ~ ~ l ~ ~ s h i n gfea~urt;U G L ~ X I I a burn through and a melt through
is that a burn throughresults in an openhole on the ID of the pipe.
Burnthrough most often occur duringthe welding of the root pass, although it is possible for this discontinuityto
be introduced during the welding of the second layer.
L Burn through frequently occur during weld repairs, especially when the repair cavityis at the root depth. I
Visual inspection should alwaysbe performed, if possible, to confirmbum through.

Concavity
I-ION:
CAUSE!

Crack crater
DEFINITION:
A linear rupture of metal under stress.
b , ~ ~ o ~ ~ ~ ~~IRANCE:
Generally a star shaped indication with irregular, feathery?twisting lines of darker density orientedwithin a
weld crater. The discontinuity is usually shallow, therefore, the indicationmay not be aspronounced as indications
~UUU~GC.Ifrom other types of cracking.
'Impr01
B Not ad
- T
CAUSES:
4 )fthe welding arc by abruptlyremoving the arc.
4 meters of the welding procedure.
incomplete fillmg 01 ule weld crater.
REMAP
be emp
crater cr
.-.-- 3: -
I 2ONSIDERATIONS:
It is to hasized that althoughthe discontinuityand resultingradiographicindication is generally star
shaped, acking does not always take this shape.
Random raaographic indications from crater crackingmay be oriented in any directionto the weld axis.

Crack, longitudinal
(shown in the root)
DEFINITION:
A linearrupture of metal under stress.
Irregularlyshaped, feathery, twisting lines of darker density
oriented along the axis of the weld.
CAUSES:
Improper fit-up ofjoint.
Contaminationof base material.
Violation of the weldingprocedures.
Longitudinalcrackscan occurthroughout the weld; inthe centerline,
fusion lines and in the root.
Cracking can, at times, be difficultto detect due to the geometric
principles of the radiographictechnique.

Crack, transverse
DEFINITION:
A linearrwture of metal under stress.
u
&IDIOGRAPHICAPPEARANCE:
Irregularlyshaped, feathery, twisting lines of darker density
orientedperpendicularto the axis of the weld. Transversecracks are
generallytight discontinuities,thereforeproducing subtleindicationson
the radiograph.
CAUSES:
Transversecracks are generallythe result of longitudinalshrinkage
strains acting on weld metal of low ductility. Most commonlyfound in
weldjoints having a high degree of restraint.
REMARKSISPECIALCONSIDERATIONS:
Cracksmay be limited in size and completelywithin the weld metal,
but may also propagate fiom the weld metal into the adjacent heat
affected zone.
Orientationand subtlenessof the discontinuity can, at times, be
difficultto detect due to the geometric principles of the radiographic
technique.
Cracking indications can be masked in the as-welded condition.
v

Craterpits
indicatia
subtleto
DEFINITION:
An approximately circular surface condition extending into the weld in an irregular manner.
e
RADIOGRAPHICAPPEARANCE:
%e indicationwill appear as a circular dot with darker density, similarto porosity, in the root area of
lble insert welds. However, due to the irregular nature of discontinuity, the edge of the indication is usually
I~UL a5 uefined as porosity. The irregularity of the discontintinuity can produce a "halo" effect on the edge of the
guishinga craterpit fiomporosity. The radiographic indicationfrom crater pits can range fiom
nced, dependingon the severityof the pit.
CAUSE
Impr01
The in
Porosi
- xr:--.-1
.A"-
* Additi
confiinn;
~n,distin
I pronom
S:
per tennination of the welding arc.
lhering to the parameters of the welding procedure.
REMARKSISPECLALCONSIDERATIONS:
s fromcrater pits canbe misinterpreted asporosity.
ccuranywhere in the weld, while craterpits occur in the weld root area.
vlq11n~mspecrion shouldalwaysperformed, if possible to confirm crater pits.
onal radiography, e.g. putting the indication in the sidewallor profile view, may be employed to assist in
ation of the discontinuity.

Incomplete fusion of a consumable insert
DEFINITION:
Tncompletemelting of the consumableinsert without fusion and bonding to the base metal along one or
c/
F :s of the consumableinsert.
I
he axis I
n elonge
eld. The
i unifom ~tedband or localized bad of lighter density in the center of the weld image, oriented along
1 of the w L width of the band appears approximately equal to the diameter of the consumableinsert.
material
The in
material
is not fu
CAUSE
Impro!
cation n-- .
The indi lay appear in the followingways
The indcationrnav aDpear with both edges straight with abrupt density transitionsfiom the insert area to the base
I area. TI rites lack of filling or blending to the base metal, with both sides of the insert not fused.
I dication pearwith one edgehaving a smooth,gradual density transitionfiomthe insert area to the
base material area and the other edge straightwith an abrupt density transitionfiom the insert areato the base
lis indicates the former edge is blended with firsion into the adjacent base metal and the latter edgearea. ll
sed.
of the ,
S:
~ f i tUP weldjoint.
Using too low a welding current.
Using too fast of a travel speed.
An incorrect torch angle.
An improper motion or weaving technique of the torch.
b8 Visual inspectionshould alwaysbe performed, where possible, to confirmincompletefusion of the insert, when
viewed on radiographs.

Lack of fusion
DEFINITION:
Lack of complete fusion of someportion of the metal in a weld
joint with the adjacent metal. The adjacentmetal may be eitherbase
metal orpreviously deposited weld metal. When the discontinuity
occursbetween a weld bead and the adjacent base metal, the term "lack
of sidewall hion" is oftenused, does not occur in the root.
Irregularlyedged, or straightand irregularly edged lines of
darker density oriented alongthe axis of the weld. If lack 6f fusion
occursbetween weld beads, both edges of the indication may be
irregularas they indicatethe weld puddle not fusingto the contourof the
previously deposited weld beads. If the lack of fusion occursbetween a
weld bead and base metal, one edge of the indication will be straight, as
it indicates theweld puddle not fusingto the prepared base meal.
Sometimesthe lines are interspersed with darker density spots, of
varying shapes, indicating voids resulting from the lack of fusion.
CAUSES:
mcient welding current to melt the adjacent metal.
Too fast a welding speed of travel will not allow for fusionto the
adjacent metal.
Too fast a welding current to melt the adjacent metal.
Impropertorch or electrodeangle may prohibit melting of the adjacentmetal.
. Improperplacement of weld passes may cause a sharp valley to fonn.
Lack of proper access to the face of weld joint.- -
Tightly adhering oxidesresultingfrom improper cleaningof items to be welded.
REMARKS/SPECIAL CONSIDERATIONS:
Lack of fusionon the under bead side of the weld, lying in a horizontal plane, tends to be undetectable but often
the sides of lack of fusion lines tend to curl out of the horizontal plane and are recorded on the radiograph.- -
A distinguishing characteristicbetween lack of fusion and incomplete penetration is that lack of h i o n can occur
anywherein the weld and incomplete penetration occurs at the weld root.

Lack of penetration
(left - nonnal fit-up, right-mismatch)
DEFINITION:
Lack of penetration of the weld through the thicknessof thejoint or penetration which is less than
kspecified.
straightr
incompl
GRAPHIC APPEARANCE:
Straight, fine edged lines of darker density oriented alongthe axis of the weld in the area of the root. The
less of both edges of the indication's image and location in the centerof the weld image help to distinguish
etepenetration from lack of fusion.
CAUSE
Insuff
- I----
-r--
In bot
cause a
Joints
eldingcurrent or to fast travel speed.
-Irnnroya wren or electrodeangle to melt the root land.
h backing ringjoints andjoints to be welded from both sides, improper placement of initial weld pass may
sharpvalley to form at the root weld.
fromboth sides, insufficientremoval of the backside prior to welding.
s atthe7
on can b
weld roc
e promi
REMARKSISPECIAL CONSIDERATIONS:
~tand is always straight, as it is a RT indication of the actualweldjoint preparation. The
nent or subtledepending on the severityof the discontinuity.

Melt through -.
DEFINITION:
A convex or concave irregularityon the s&ce of a backing ring
or strip,
through
hole.
fbsed root or adjacent base metal resulting from fusingcomple
a localizedregion but without development of a void or open
A localized area, usually rounded, and generally found at the
center of the weld image. The density of the indication appearslighter
when the discontinuity is convex and darkerwhen the discontinuityis
concave.
CAUSES:
Using a weld currenthigherthan allowedby the welding procedure.
Improperlypreparing the tungsten electrodetip.
Using too slow a welding speedof travel will cause overheating.
Improper fit up of the weldjoint (unacceptable root gap).
REMARKS/SPECIAL,CONSIDERATIONS:
The entire thickness of metal is melted or re-melted and deforms,m
hole or void developsas with a burn through.
Melt through most often occurs duringthe welding of the root pass,
although it is possible for this discontinuity to be introduced duringthe welding of the second layer. Visual
inspection should alwaysbe performed, if possible, to confirm melt through.
u

Offset
(misalignment/rnismatch,shown with LOP)
DEFINITION:
'L
Lateral misalignment of two buttjoint members of equal
thickness.
Offset on piping weldjoints can appear on the film in different
ways. The radiographic image is dependentupon the orientationof the
offset to the beam of radiation. When the offset condition is parallel to
the beam of radiation,the offset image may appear as an abrupt
density change, generally half m y across the width of the weld image.
When the offset condition is perpendicularto the beam of radiation,
and the entire image of the item is on the film, the offset image will
appear in the sidewall orprofile view, as lateralmisalignment of the
members with a high-low effect of the pipes' ID and OD.
CAUSES:
Improper fit-up or fixturingmay cause the members to be offset.
Improperweldingblock sequencingonthe root pass.
Visual inspectionshouldalwaysbe performed to confii questionable offset conditionswhen viewed on
radiographs.

Oxidation
DEFINITION:
A condition resulting frompartial or complete lack of purge of a surfacewhich is heated during weldiv
resulting in formation of oxide on the surface.This condition may range from slight oxidationthrough the u
formation of heavy black scaleto the extreme of a very rough surfacehaving a rough crystalline appearance.
OGRAPHICAPPEARANCE:
Highly irregular,low density area, with a wrinkled or sugared appearance in the center of the weld image.
The conditionmay extend for the entire circumference of the weld when there is a complete loss of purge. The
conditionmay only be localized, in one or more areas of the weld, occurring wheneverthe purge is partially
interrupted.
CAUSES:
*,Loss of internalpurge gas resulting in an unshielded molten weld puddle on the ID.
High oxygencontent in purge gas orpath.
Moisture in the area of the weld, due to inadequate drying of thepurge path, leakage, etc...
Avisual inspectionshould alwaysbe performed, if possible, to confirm oxidation.
Oxidationgenerally occursduringthe flowingof the weld root. However, this condition may occur during
welding if there is a degree of rootreflow, loss of purge, or moisturepresent. Oxidation frequently occursduring
weld repairs.

Overlap(re-entrant angle)
DEFINITION:
Theprotrusion of weld metal beyond the weld toes or weld root.
sidewall
at the fu:
phic im2
r is not ;
-..&+L ..d -
or profi
sion line
",~IOGRAPHIC APPEARANCE:
3verlapconditionson the OD of piping butt weldjoints shouldbe an extremelym e occurrencein asmuch
i ;factoryVT and other surface inspections, such as PT or MT are required prior to RT. However, overlap
on ult: mternal weld surfaceconsumable insert piping weld butt joints can appear on the filmin different ways. The
I ige is dependent upon the orientation of the overlap to the beam of radiation. When the overlap
located in the sidewall orprofile view, the overlap image will appear consistentwith that of
C u l ~ v c n l r vWIU~ an abrunt density change at the fusion line of the weld root image. When the offset image is in the
! it will appear as roll over of the weld root reinforcement with an unsatisfactoryblending
i weld root image.
- I
le view,
:ofthe
S:
I
ow of a welding speed.
.roolow ortoo hi& of a welding current.
M e angle.ect torch
-
I or elecl
Visual inspection should alwaysbe performed, wherepossible, to confm questionableroot surface conditions
when viewed on radiographs.
Inspector's Harrdbook 7-39

Porosity
(right-clustered porosity, bottom left -distributedporosity, bottom
right -aligned porosity in the root)
DEFJNITION:
Gas pockets or voids in weld metal.
Usually spherically shapedareas of darkerdensity and may be
scatteredthroughoutsinglepass welds or throughout severalpasses of
multiplepass welds. Althoughusually sphericalin shape,porosity may
also occur as nonsphericalpockets and appear on the radiograph as
elongatedvoids, sometimesreferred to as "pipingorwormhole
porosity". The density of the indicationvaries directlywith the diameter
or magnitude of the pore.
CAUSES:
Faulty welding techniques such asusing too longan arcwith the
SMAWprocess.
Impropercleaning of the weld joint.
None.

Root razorback condition
DEFINITION:
An oxide membrane, gray in color, with a sharp ridge or peak and ribs fi.omthe peak to the edge giving it a
L
'ierringboneeffect. Also known as "reverse center line crease."
The image of root razorback is consistentwith that of convexitywith an associatedherringbone appearance
and sharppeak at the center. The lightest density of the image is in the center and is dependentupon the height of
peaked condition. The density of the image gradually increases as the condition blends into the base metal.
CAUSES:
Moisture in the area of the weld. Moisture in the purge gas.
This is one of the most commonroot surface defects encountered when welding NiCu and Ni-C-r-Fe.
Visual inspection should alwaysbe performed, where possible, to confm root razorback conditionwhen viewed
on radiographs.

Root surfacecenterline crease
DEFINITION:
An intermittent or continuousperipheral centerlineconcavityfonned on the root surface.
I 4
The image of centerlinecrease is consistentwith that of concavity with an associatedherringbone
appearance. If the crease has a notch or a questionableblending conditionat the center, the image will crease
oriented along the axis of the weld.
CAUSES:
Thick coverpass over a consumableinsert that had minor concavity. Excessive welding current.
Visual inspection should always be preformed,where possible to confm questionablecenterlinecreasewhen
viewed on radiograph.
Approved workmanship sampleradiographsmay be employed to evaluatecenterline creasewhen a visual
inspection is not possible.
Inspector9sHandbook

Root surfaceconcavity
DEFINITION:
A depressionon the root surface of the weld, which may be dueto
L/
-pvity,internal purge or shrinkage.
The image of concavitymay appear as intermittent elliptical areas
or elongatedbands of darker filmdensity oriented alongthe axisof the
weld in the center of the weld image. The width of the image is consistent
with the weld root width. The darkest density of the concavity's image is
generally in the center and is dependent up6n the depth of the concavity.
The density of the image gradually decreases as the concavityblends into
the base metal.
CAUSES:
. Improper fit up of the weldjoint.
Using too high of a'welding current, too slow of a travel speed, or
extremely high purge gas flow rate.
Visual inspectionshould alwaysbe preformed, where possible to
confirmquestionableconcavity when viewed on radiograph.

Root surface convexity
I TION:
Reinforcement of tkroot surfaceof a butt-ksed typeweld. I
4
The image of convexitymay appear as intermittent ellipticalareas or elongatedbands of lighter film
densityoriented along the axis of the weld in the center of the weld image. The widthof the image is consistent
with the weld root width. The lightest density of the convexity's image is generallyin the center and is dependent
upon the height of the convexityblends into the base metal.
CAUSES:
Using to low or high of a welding currert. Using too slow travel speed when welding.
Visual inspectionshould always be performed, when possible, to confirm questionableconvexitywhen viewed
on radiographs.

Slag,
DEFINITION:
Non-metallic solid material entrappedin weld metal or
b'ptween weld metal and base metal.
.2
Well defined,irregularlyshaped, uniformly darker density
areas usually elongatedalong the axis of the weld.
'Impr01
between
-
Slagis
roods. T
-- -
-
too low
welding
3n.
nxbead
+LaL,,,
per inter
.---,---
(
unproper 111-up,sucn as maequate bevel of thejoint sides.
Using a weldin ~tfor the size of electrode.
Faulty :techniq 1as wrong electrodeposition or
orientatic
I znt causing sharp valleys or undercutting
1
mpro] slag from the surface.
r a bypr
hus, slag
placemt
is.
kg currer
ues sucl
pass clel
oduct of
g inclusi~
.a,... a,.,
'the bur^
OnS are i
.....+I...-.
REMARKSISY~CIALCUNSIOERATIONS:
ning of the flux covering on welding
asociated with the SMAWprocess.
Slaghlulw~v~law -UJ ull~rlghoutthe weld, in the center of the
welcl-in fusion lines and in the r&t.
'v
Inspectds Handbook

Tungsten inclusion
DEFINITION:
Metallic tungsten inclusions in the weld deposit.
Irregularlyshaped spots of low film density areas, usually
random in size and location. They are solid or liquid bits of tungsten
electrodefrom the TIG weldingprocess that drop or are melted fromthe
electrode and become entrapped in the weld puddle. Tungsten inclusions
appearas low or light density areas on the radiograph because of the
differences of radiographicabsorption between the inclusion and
surroundingmetal. stenenis dnwrradi6graphicallythen the
surroundingmetal and thereforeabsorbsmore radiation. This, in turn,
allows fewer rays to reach the film.
CAUSES:
Overheatingthe tungstenelectrodedue to excessivecurrent for the
particular electrode size.
DpfPctive tungsten electrode(flakingof particles).
ing the tungsten molten puddle.into the
--*-
m Dipp
None.

Undercut
.tl
he base I
DEFINITION:
Anintermittent or continuous groove on the external surface of
metal along the edge of the weld.
51
kAuluGWHlc MY~ARANCE:
airregular, elongated area of darker density oriented along the
extamdl h i o n line of the weld image to the base metal.
using
8 using
rrn
filler me
An inc
too long
excessiv
. .'a
cxccsslve welding current.
t an arc lengthwill result in a gouging effect.
I ,ewelding speed of travel.
wnen uslng me GTAW process, adding an -cient amount of
ectrode angle can cause a gouging effect.
acceptar
Visual
ice Visu
i inspect:
inspec
ion shou
. .
Externalundercut is readily revealed and dispositionedupon
:tion.
Id alwaysbe performed to confirmquestionable
extema unaercut wnen viewed on radiographs.
- Inspector's Handbook 7-47

Undercut, root -
DEFINITION:
An intennittent or continuousgroove in the internal surface of
the base metal, backingring/strip along the edge of the root of the weld.
)GRAPHIC APPEARANCE:
An irregular, elongated area of darkerdensityoriented alongthe
lnternai h i o n line of the weld imageto the base metal.
filler m
mproperla up of the weldjoint.
Excessive current duringwelding
When using the GTAWprocess, adding an insufficient amount of
incorrectelectrodeangle can cause a gouging effect.
Radic
based c..
KEMARKS/SPECIAL CONSIDERATIONS:
evaluationof root undercut in backing ringjoints can be
nanship sampleradiographs aswell as the use of slotted
7-48 ImyectoISsHandbook

Weld splatter
DEFINITION: .
In arc welding, the metal particles expelled duringweldingwhich do not form a part of the weld.
iL/
, RADIOGRAPHIC APPEARANCE:
Small, rounded areas of lighter density generally found adjacent to the edge of the weld image on the base
metal.
CAUSES:
There will be someweld spatterwhen using the SMAWprocess. However, long arcing is a factor.
Lack of concentricityor damageto the electrode flux.
Weld splatter is most commonly found when the SMAWweldingprocess is employed.
Weld spatteris generallyrevealed and dispositionedupon acceptanceVisual inspection. However, weld spatter
may occur from another welding operation in the area afterthe acceptanceVTPT inspectionsand prior to the RT.

. -
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Probable Causes and Corrective Action for Automatic Film Processing
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