1 / 23

Non Destructive Examination

Non Destructive Examination . (NDE). 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. NDE . All Welds have flaws.

jeb
Download Presentation

Non Destructive Examination

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Non Destructive Examination (NDE)

  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. NDE • The purpose of welding inspections is to locate and determine the size of any discontinuities • Discontinuities that are to large or repeat too often within the weld become defects • Defects will compromise the welds overall strength

  5. What are some common defects? • Porosity • Undercutting • Rollover or “Cold Lap” • Slag inclusion • Poor penetration • Voids • Hydrogen Embrittlement

  6. Typical faults in a finished weld.

  7. How would you find these faults ? Non Destructive Examination NDE

  8. Common methods used in NDE • Visual Inspection (VT) • Magnetic Particle Inspection (MT) • Liquid (Dye) Penetrant Inspection (PT) • X-Ray inspection (RT) • Ultrasonic testing (UT) • Air or water pressure testing (LT)

  9. Visual Inspection (VT) • Visual is the most common inspection method • VT reveals spatter, excessive buildup, incomplete slag removal, cracks, heat distortion, undercutting, & poor penetration • Typical tools for VT consist of Fillet gauges Magnifying glasses, Flashlights, & Tape measures or calipers.

  10. Fillet gauges measure The “Legs”of the weld Convexity (weld rounded outward) Concavity (weld rounded inward) Flatness Visual Inspection (VT)

  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- Rays • An 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 purposes • RT 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 intothe 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 time • True or False ? • Dye penetrate inspections can only be used on non magnetic material. • Answer: False

  17. Quiz time • True or False ? • X-Rays can only be used to locate flaws at or near the surface of a weld. • Answer: False

  18. Quiz time • True or False ? • Virtually all welds have flaws. • Answer: True

  19. Quiz time • True or False ? • Magnetic particle testing can only detect flaws at or near the surface. • Answer: True

  20. Quiz time • True 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 inspection B: nondestructive evaluation C: nondisruptive evaluation D: nondestructive examination

  22. Quiz time • The 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: hydrostatic B: mass spectrometer C: soap suds bubble D: scleroscope

  23. Modern WeldingYork County School of Technology

More Related