2 Non Destructive Examination (NDE) Non Destructive Examination is the act of evaluating a welded component (or material to be welded) without affecting the serviceability of the part or material.
3 NDE All Welds have flaws. Another name for a flaw is a discontinuity Discontinuities are interruptions in the normal crystalline structure (or grain) of the metal.Discontinuities are NOT always defects
4 NDEThe purpose of welding inspections is to locate and determine the size of any discontinuitiesDiscontinuities that are to large or repeat too often within the weld become defectsDefects will compromise the welds overall strength
5 What are some common defects? PorosityUndercuttingRollover or “Cold Lap”Slag inclusionPoor penetrationVoidsHydrogen Embrittlement
11 Magnetic Particle Inspection (MT) Magnetic Particle Inspection (commonly referred to as Magnaflux testing) is only effective at checking for flaws located at or near the surface.MT uses a metallic power or liquid along with strong magnetic field probes to locate flaws. (Particles will align along voids)MT can only be used on materials that can be magnetized
12 Liquid (Dye) Penetrant Inspection (PT) Liquid penetrant inspection uses colored or fluorescent dye to check for surface flaws.PT will not show sub-surface flaws.PT can be used on both metallic and non metallic surfaces such as ceramic, glass, plastic, and metal.PT dose not require the part to be Magnetized.
13 X-Ray inspection (RT)Welds may be checked for internal discontinuities my means of X- RaysAn X-Ray is a wave of energy that will pass through most materials and develop the negative image of what it passes through on film.A Radiograph ( X-Ray picture) is a permanent record of a weld used for quality inspection purposesRT inspections can reveal flaws deep within a component
14 Ultrasonic testing (UT) Ultrasonic testing (UT) is a method of determining the size and location of discontinuities within a component using high frequency sound waves.Sound waves are sent through a transducer into the material and the shift in time require for their return or echo is plotted.Ultrasonic waves will not travel through air therefore flaws will alter the echo pattern.
15 Air or water pressure testing (LT) Pressure testing or leak testing can be performed with either gasses or liquids.Voids that allow gasses or liquids to escape from the component can be classified as gross (large) or fine leaks.Extremely small gas leaks measured in PPM (parts per million) require a “Mass Spectrometer” to Sniff for tracer gases
16 Quiz timeTrue or False ?Dye penetrate inspections can only be used on non magnetic material.Answer: False
17 Quiz timeTrue or False ?X-Rays can only be used to locate flaws at or near the surface of a weld.Answer: False
18 Quiz timeTrue or False ?Virtually all welds have flaws.Answer: True
19 Quiz timeTrue or False ?Magnetic particle testing can only detect flaws at or near the surface.Answer: True
20 Quiz timeTrue or False ?Magnet particle testing can only be done on materials that can be magnetized.Answer: True
21 Quiz time The letters NDE Mean ___________ ? A: nondestructive inspectionB: nondestructive evaluationC: nondisruptive evaluationD: nondestructive examination
22 Quiz timeThe method most often used to check for leaks as small as one part per million (PPM) from a gas line or cylinder is the _________ Method ?A: hydrostaticB: mass spectrometerC: soap suds bubbleD: scleroscope
23 Modern Welding York County School of Technology
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