An Overview of Forging Process and Defects in Hot and Cold Forging

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 09 Issue: 07 | July 2022 www.irjet.net p-ISSN: 2395-0072
© 2022, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 1038
An Overview of Forging Process and Defects in Hot and Cold Forging
Sanjay kumar1, Kharat Anand Babasaeb2, Khotkar Saurabh Dipak3
123Student of second year B-Tech of Mechanical Engineering Department, Deogiri Institute of Engineering and
Management Studies College.
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Abstract - Forging is the manufacturing technology of
shaping the essence piece into the asked shape. The forging
operation are performed with the help of forged hammer or
die. This technology is extensively used in the industry for
making the well-defined shape of the material. The different
types of operation are performed in forging are fullering,
bending, jumping, andedging byperformingforgingoperation
various defects occur in both hot and cold forging process due
to indecorous design of forging die, excessive chilling in
forging product, residual stresses, cold shut, flakes, and sharp
corner. The ideal of this review paper to understand the
forging process and colorful blights means defects of both hot
and cold forging operation in detail.
Key Words: - Forging, Types of forging, Forging defects
and Advantages and disadvantages of hot and cold forging.
1. INTRODUCTION:
Forging is a metal forming manufacturing process involving
the shape of the metal using compressive forces (i.e.,
Hammer or die). According to temperature forging are
classified into two types. Cold forging and Hot forging.Inhot
forging operation are carried out at above the
recrystallisation temperature of the metal. In cold forging
are carried at or near room temperature. Forging processes
are widely used in manufacturing industries for producing
large numbers of product like automotive, aerospace,
hardware, machine, hand tools, jewelry etc. Today forging is
a major worldwide industry because forging process can
create parts that are strongerthanothermanufactured parts
like casting. Therefore, forging is always used where
reliability and human safety are critical such as airplanes,
poor heating, less raw material used,excessivechillingofthe
forged product, sharp automobiles, tractors, ships, engines
oil drilling equipment etc. There are different types of
forging operations like Open die forging or Smith forging,
Impression die forging, Flash less forging, roll forging and
Machine forging or Upset forging. But there are different
types of defects occur in forging due to poor design of a die,
corners of the object. Some other defects occur due to rapid
cooling of forged parts, using light hammer blows and one
more type of defects occur when dies are not aligned with
each other. Advantages of forging process are it is stronger
than casting products, it improves the strength of the
material, it can be easily welded etc.
2.Literature Summary:
Forging is a manufacturing process in which material is
shaped by the operation of localized compressive forces
applied manually or with power hammers, special forging
machines or press. It may be carriedoutonaccoutrementsin
either hot or cold state. When forging is done cold process
are given special names. Therefore, the term forging
generally implies hot forging carried out at temperatures
which are above the recrystallization temperature of the
material.
Forging is an effective system of producing multitudinous
useful shapes. Forging process is applied to produce
separate corridor. Typical forged corridor includes rivets,
bolts, coil hooks, connecting rods, gears,turbineshafts,hand
tools, roads and a variety of structural factor used to
manufacture ministry.Theforgedcorridorhasgoodstrength
and continuity; they can be usedreliablyforlargelystressed-
out and critical operations.
Table -1: Literature survey
3.Forging Operation:
1) Drawing Down: It is the process of outstretch the length
and reduce the sampling area of the workpiece. Simply in
this operation the length of workpiece increases, and cross
Serial
Number
Title Of Paper Author Name and year
1) Smart DiagnosticExpert
system for defects in
forging processbyusing
Machine
Learning Process
S Mewada, A Saoliya,
N Chandramouli in 2022
2) Analysis of forging
defects for selected
industrial die forging
process
Marek Hawryluk,Joanna
Jakubik in 2016
3) An overview of forging
processes with their
defects
MG Rathi, NA Jakhade in
2014
4) Investigation of defects
in forging tools by Non-
destructive detection
method
D Stancekova, A Czan, M
Derbas in 2013

section area diminishments. In forging process, a
compressive force is applied at vertical directionofitslength
axis. If, a tensile force is applied to change its length at
resemblant to its length axis this process isknownaswire or
line delineation.
2) Upsetting: Capsizing is just contrary operation to
drawing down operation. In this operation the length of
workpiece diminishments, and its cross-section area
increases. In this process, a compressive force is applied at
resemblant direction to its length axis.
3) Edging: It is a type of open die forging in which forging
operation are carried out at the edges of the workpiece. In
this operation the workpiece is forged to a desired shape by
using dies to compress the materials.
4) Bending: In bending operation the force is applied to a
piece of distance metal which causes it to bend at an asked
shape.
5) Punching: Punching operation is carried out using a die
and punch to produce holes in a distancesubstanceormetal.
6) Forged welding: It is a metal joining process in which
two pieces of metal are joined with each other to elongate its
length. For illustration, to forge the steel sword it is first
heated at a temperature of 1050 Degree Celsius to 1150
Degrees Celsius and it is brought together and hammered or
pounded.
7) Swaging: In this operation the workpiece is reduced to a
desired shape generally round shape or hexagonal shape.
For small workpieces the top and the nethermostswagepair
is used to shape the metal while, for large workpieces the
swage block is used.
4. Types of forging:
1) According to the temperature:
a) Hot Forging: If the work piece is hotter above its
recrystallization temperature is known as hot forging. The
recrystallization temperature is defined as the temperature
at which the new grains are formed in the essence. This kind
of extreme heat is necessary in avoiding strain hardening of
the essence during distortion.
Advantages High strain rates and hence easy inflow of the
essence, Recrystallization and recovery are possible, Forces
needed are less.
Disadvantages Lubrication is delicate at high temperatures,
Oxidation and scaling do on the work piece, Poor surface
finish due to overheat, less precise forbearance, Possible
screwing of the material during the cooling process.
Table- 2 Temperature range of different metals or
alloy
b) Cold Forging: If the work piece is heated at room
temperature is known as cold forging. To get more accurate
dimension and face finish we use warm forging.
c)Warm Forging: In warm forging work piece is heated
above the room temperature but below the recrystallization
temperatures.
Advantages: Product rates are veritably high with
exceptional bones life, improves mechanical parcels, lower
disunion between bones face and work piece, Lubrication is
easy, no oxidation or spanning on the work.
Disadvantages: Residual stress maydo,Heavierandfurther
important outfit is demanded, Stronger tooling is needed,
Tool design and manufacturing are critical.
Fig.1- Graph of Hot Warm and Cold forging
2) According to the arrangement of die:
a) Open die forging: This forging process uses flat dies or
no die. This is hot forging processinwhichworkpieceheated

and pounded to gain desired shape. This process produces
rough product.
b) Close die forging: In close die forging set up impression
dies used to produce desired shape on workpiece
substantially these products do not need any finishing
process. This process needed advanced force.
3) According to the forging equipment:
a) Smith forging:
b) Drop forging:
c) Press forging:
d) Machine forging.
5. Defects in Hot and Cold forging:
1)Unfilled section: In unfilled section defects some of the
forging section remain unfilled because off the indecorous
design or improper heat treatment of metals. Minimum use
of raw material or due to poor heating cause major defects.
Remedies: This disfigurement can be removedbyproper die
design, proper use of raw equipment and proper heating.
2) Cold shut: In cold shut forging defects at the cornerofthe
object. This type of defect arises due to improper design of
the forging die, sharp corner of the object, excessive chilling
of the forge product creates small cracks at the corner.
Remedies: The fillet radius of the die is to be increased and
working temperature should be maintainincaseofcoldshut
defects.
3) Scale pits: It is usual in forging carried in open
environment and it causes irregular deputations on the
forging surfaces. This type of forgingdefects producesdue to
unethical cleaning of the outer forged surface.
Remedies: This defect can be avoided by adequate cleaning
of forged surface.
4) Die shift: When the upper and lower dies are mismatch
and not aligned which produce defects and don’t provide
accurate dimensions. This will lead to improper dimensions
of the product.
Remedies: Both the upper and lower are properly aligned
with each other. It can be removed by keepinghalfportionof
the workpiece on the upper die and half on lowerdie.Sothat
the portion can match.
5) Flakes: It is internal cracks caused when both forged
products cool quickly, or impropercoolinganditreducesthe
strength of that product.
Remedies: proper cooling and flakes can be avoided when
cooling is performed.
6) Surface cracking: This type of defects arises when the
forging operation is done at low temperature or below
recrystallization temperature in which cracks occur on the
workpieces.
Solution: It can be controlled by working on proper
temperature, so strength of the material gets increases.
7) Incomplete forging penetration: This forging defect
occurs when forging takes place only at the surface. At the
interior of the forging material dendritic ingot structure is
not broken. This is caused using light rapid hammer blow.
Remedies: Use forging press for full penetration, use heavy
hammer.
8) Residual stresses:Inresidual stressforgingdefectstakes
place when the forged parts of the material are not properly
cooled. It can be caused by rapid cooling.
Remedies: It can be prevented by slow cooling of the forged
parts.
Fig.2 Forging Defects.
6. CONCLUSIONS
Forgings occasionally bring further than corridor produced
by other processes or like casting machining, but it
gives further dependable corridor with better mechanical
and metallurgical parcels.
time with little or noscrap. therefore, there's saving in
energy and material.
Forging is an experience acquainted process. Throughout
the times,a great deal ofknow style and experience has been
accumulated in this field, largely by trial- and- error styles.
Forging processes produces final products in veritably short

ACKNOWLEDGEMENT:
I would like to thank all who support me and give guidance
throughout the work. I would thankstoall theassociatesand
all my friends for furnishing me the help whenever I
demanded it most. I will ever remain obliged to all those
people who directly and laterally inspired me to complete
this exploration. I would like to give my special thanks to
Professor: Sachin Borse, Department of Mechanical
Engineering who guide me and partake the knowledge with
me about exploration paper.
REFERENCES
[1] C.J. Van Tyne and J. Walters- “Understandinggeometrical
forging defects”- April 1, 2007
[2] H. James Henning- “Defects in Hot Forging”- May/June
2007
3] Chandna, P and Chandra, A. (2009), “Quality tools to
reduce crank shaft forging defects: an industrial casestudy”,
Journal of Industrial and SystemsEngineering,Vol.3No.1, pp.
27-37
[4] M.G.Rathi and N.A.Jakhade (2014), “An Effect of forging
process parameters on filling the job weight::An industrial
case study”, International Journal of scientific and Research
Publications, Vol.4No6.
[5] M.G.Rathi and N.A.Jakhade (2014), “An Overview of
Forging Processes with their defects”, International Journal
of scientific and Research Publications, Vol.4No6.
[6] M.S.Sekhon,G.S.Barr and Sukhrajsingh.(2014),“A six
sigma approach to detect forging defects in a small scale
industry: A case study”, International Journal ofEngineering
and Technical Research Publications, Vol.2No8, pp.33– 40.
[7] V. Chand, S.S.Sen and M.S.Sethi (2014), “Taguchi analysis
of forging defects for gears”, International Journal of
Advance Technology and science Publications, Vol.2No8
BIOGRAPHY
1.Sanjay kumar Pursuing B-tech
in Mechanical from Deogiri
Institute of Engineering and
Management Studies College
(Aurangabad).
2.Kharat Anand Babasaeb
Pursuing B-tech in Mechanical
from Deogiri Institute of
Engineering and Management
Studies College (Aurangabad).
3.Khotkar Saurabh Dipak
Pursuing B-tech in Mechanical
from Deogiri Institute of
Engineering and Management
Studies College (Aurangabad).
Since blights causes high rejection rates, it's important to
move any process inthe direction of barring all defects as part
of an effective nonstop enhancementprogram.
A good quality program begins with a station ofmaking it
right the first time. Forging processes are no exception to
this. Economically, as well as from a quality perspective,
it’s better to understand and control the process to avoid
blights rather than scrapping the imperfect corridor during
final examination.

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