NON DESTRUCTIVE TESTING TECHNIQUES
- 1. RAJ KUMAR GOEL INSTITUTE OF TECHNOLOGY, GHAZIABAD (U.P),201003. NON DESTRUCTIVE TESTING Under The Supervision Of Mr. ABHINAV BHARTI. Presented By : SHIVAM GUPTA (1203340149)
- 2. The use of noninvasive techniques to determine the integrity of a material, component or structure or quantitatively measure some characteristic of an object. i.e. Inspect or measure without doing harm.
- 3. Flaw Detection and Evaluation Leak Detection Location Determination Dimensional Measurements Structure and Microstructure Characterization Estimation of Mechanical and Physical Properties Fluorescent penetrant indication
- 4. › To assist in product development › To screen or sort incoming materials › To monitor, improve or control manufacturing processes › To verify proper processing such as heat treating › To inspect for in-service damage There are NDE application at almost any stage in the production or life cycle of a component.
- 5. Most basic and common inspection method. Tools include fiberscopes, borescopes, magnifying glasses and mirrors.
- 6. • A liquid with high surface wetting characteristics is applied to the surface of the part and allowed time to seep into surface breaking defects. • The excess liquid is removed from the surface of the part. • A developer (powder) is applied to pull the trapped penetrant out the defect and spread it on the surface where it can be seen. • Visual inspection is the final step in the process. The penetrant used is often loaded with a fluorescent dye and the inspection is done under UV light to increase test sensitivity.
- 7. Advantages of Liquid Penetrate Testing 1.Simplicity of operation. 2.Best method for surface breaking cracks in non-ferrous metals. Disadvantages of Liquid Penetrate Testing 1.Restricted to surface breaking defects only. 2.Decreased sensitivity . 3.Uses a considerable amount of consumables
- 8. The part is magnetized. Finely milled iron particles coated with a dye pigment are then applied to the specimen. These particles are attracted to magnetic flux leakage fields and will cluster to form an indication directly over the discontinuity. This indication can be visually detected under proper lighting conditions.
- 9. Advantages of Magnetic Particle Crack Detection Simplicity of operation and application. Quantitative. Can be automated, apart from viewing. (Though modern developments in automatic defect recognition can be used in parts of simple geometry e.g. billets and bars. In this case a special camera captures the defect indication image and processes it for further display and action) Disadvantages of Magnetic Particle Crack Detection Restricted to ferromagnetic materials. Restricted to surface or near surface flaws.
- 10. The radiation used in radiography testing is a higher energy (shorter wavelength) version of the electromagnetic waves that we see as visible light. The radiation can come from an X-ray generator or a radioactive source. High Electrical Potential Electrons -+ X-ray Generator or Radioactive Source Creates Radiation Exposure Recording Device Radiation Penetrate the Sample
- 11. Top view of developed film X-ray film The part is placed between the radiation source and a piece of film. The part will stop some of the radiation. Thicker and more dense area will stop more of the radiation. = more exposure = less exposure The film darkness (density) will vary with the amount of radiation reaching the film through the test object.
- 12. Advantages of Radiography Information is presented pictorially. A permanent record is provided which may be viewed at a time and place Distant from the test. Useful for thin sections. Sensitivity declared on each film. Suitable for any material. Disadvantages of Radiography Generally an inability to cope with thick sections. Possible health hazard. Need to direct the beam accurately for two-dimensional defects
- 13. High frequency sound waves are introduced into a material and they are reflected back from surfaces or flaws. Reflected sound energy is displayed versus time, and inspector can visualize a cross section of the specimen showing the depth of features that reflect sound. f plate crack 0 2 4 6 8 10 initial pulse crack echo back surface echo Oscilloscope, or flaw detector screen
- 14. Gray scale image produced using the sound reflected from the front surface of the coin Gray scale image produced using the sound reflected from the back surface of the coin (inspected from “heads” side) High resolution images can be produced by plotting signal strength or time-of-flight using a computer- controlled scanning system.
- 15. Advantages: 1. High penetrating power, which allows the detection of flaws deep in the part. 2.High sensitivity, permitting the detection of extremely small flaws. 3 Some capability of estimating the size, orientation, shape and nature of defects. 4.Capable of portable or highly automated operation. Disadvantages: 1. Manual operation requires careful attention by experienced technicians 2. Extensive technical knowledge is required 3. Surface must be prepared by cleaning and removing loose scale, paint, etc, although 4.scattering by test material structure can cause false indications. 5. not easily applied to very thin materials
- 16. Inspection of Raw Products Inspection Following Secondary Processing In-Services Damage Inspection
- 18. Cracking Corrosion Erosion/Wear Heat Damage etc.
- 19. Special cars are used to inspect thousands of miles of rail to find cracks that could lead to a derailment.
- 20. • India has a number of bridges. • Corrosion, cracking and other damage can all affect a bridge’s performance. • Bridges get a visual inspection about every 2 years. • Some bridges are fitted with acoustic emission sensors that “listen” for sounds of cracks growing.
- 21. NDT is used to inspect pipelines to prevent leaks that could damage the environment. Visual inspection, radiography and electromagnetic testing are some of the NDT methods used. Remote visual inspection using a robotic crawler. Radiography of weld joints. Magnetic flux leakage inspection. This device, known as a pig, is placed in the pipeline and collects data on the condition of the pipe as it is pushed along by whatever is being transported.
Editor's Notes
- #20: The heavy loads that trains place on the railroad tracks can result in the formation of cracks in the rail. If these cracks are not detected, they can lead to a derailment. Special rail cars equipped with NDT equipment are used to detect rail defects before they are big enough to cause serious problems.
- #21: The US has 578,000 highway bridges, which are the lifelines of US commerce. Corrosion, cracking and other damage can all affect the bridges load carrying capacity. Therefore, all of the elements that directly affect performance of the bridge including the footing, substructure, deck, and superstructure must be periodically inspected or monitored. Visual inspection is the primary NDE method used to evaluate the condition of the majority of the nation's highway bridges. Inspectors periodically (about every two years) pay each bridge a visit to assess its condition. However, it is not uncommon for a fisherman, canoeist and other passerby to alert officials to major damage that may have occurred between inspections. The potential penalties for ineffective inspection of bridges can be very severe. Instances of major bridge collapse are very rare, but the results are truly catastrophic. The collapse of the famous Silver Bridge at Point Pleasant, Ohio in 1967 resulted in loss of 47 lives. The cost of this disaster was 175 million dollars but some experts estimate the same occurrence today would cost between 2.1 and 5.6 billion dollars. Furthermore, these cost figures do not take into account factors such as loss of business resulting from loss of access or detours, the cost resulting from blockage of a major river shipping channel, and potential environmental damage due to hazardous materials being transported over the bridge at the time of collapse. Fatigue cracking and corrosion will become increasingly important considerations as we go beyond the 75 year life expectancy and current visual inspection techniques will not suffice. The life extension approach will require increased use of NDE in a coordinated effort to obtain reliability assurance for these structures. NDE techniques such as magnetic particle inspection and ultrasonic inspection are being used with greater frequency. One of the newer NDE technologies being used is acoustic emission (AE) monitoring. Some bridges are being fitted with AE instruments that listen to the sounds that a bridge makes. These sophisticated systems can detect the sound energy produced when a crack grows and alert the inspector to the cracks presence. Sensors can be permanently fixed to the bridge and the data transmitted back to the lab so that continuous bridge condition monitoring is possible. The image provided here shows field engineers installing an AE monitoring system on the lift cables of the Ben Franklin Bridge in Philadelphia, PA