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  1. 1. Nondestructive Testing
  2. 2. Common NDT Methods <ul><li>Liquid Penetrants </li></ul><ul><li>Ultrasonic </li></ul><ul><li>Magnetic Particle </li></ul><ul><li>Eddy Current </li></ul><ul><li>Radiographic </li></ul><ul><li>Acoustic Emissions </li></ul><ul><li>Visual </li></ul><ul><li>Special Methods </li></ul>
  3. 3. Liquid Penetrants <ul><li>Liquid Penetrant </li></ul><ul><li>Test objects or material is coated with visible or fluorescent dye solution. </li></ul><ul><li>Excess dye is then removed from the surface, and a dry developer is applied. </li></ul><ul><li>The developer acts as blotter, drawing penetrant out of imperfections open to the surface. With visible dyes, vivid color contrasts between the penetrant and developer make bleedout; easy to see. With fluorescent dyes, ultraviolet light is used to make the bleedout fluoresce brightly, thusallowing imperfections to be seen readily. </li></ul>
  4. 4. Liquid Penetrants <ul><li>4 Basic steps to test. </li></ul>
  5. 5. Liquid Penetrants <ul><li>Portable Equipment </li></ul>
  6. 6. Liquid Penetrants <ul><li>High-Production Equipment </li></ul>
  7. 7. Ultrasonic Testing Ultrasonics uses transmission of high‑frequency sound waves into a material to detect imperfections within or to locate changes in material properties. The most commonly used ultrasonic testing technique is pulse echo, wherein sound is introduced into a test object and reflections (echoes) are returned to a receiver from internal imperfections or from the part's geometrical surfaces.
  8. 8. Ultrasonic Testing <ul><li>Thickness Tester </li></ul>
  9. 9. Ultrasonic Testing <ul><li>Thickness and Discontinuity tester </li></ul>
  10. 10. Ultrasonic Testing <ul><li>Straight-Beam Transducers </li></ul>
  11. 11. Ultrasonic Testing <ul><li>Angle-beam Transducers </li></ul>
  12. 12. Ultrasonic Testing
  13. 13. Magnetic Particle Testing <ul><li>Portable Equipment </li></ul>
  14. 14. Magnetic Particle Testing <ul><li>Magnetic Particle </li></ul><ul><li>This method is accomplished by inducing a magnetic field in a ferromagnetic </li></ul><ul><li>material and then dusting the surface with iron particles (either dry or suspended in liquid). Surface imperfections distort the field and concentrate iron particles near imperfections </li></ul>
  15. 15. Magnetic Particle Testing
  16. 16. Magnetic Particle Testing
  17. 17. Magnetic Particle Testing <ul><li>High Production fixed Station </li></ul>
  18. 18. Magnetic Particle Testing <ul><li>Test Method </li></ul>
  19. 19. Eddy Current Testing Electromagnetic (Eddy Current) Electrical currents are generated in a conductive material by an induced alternating magnetic field. Interruptions in the flow of electric currents (eddy currents), caused by imperfections or changes in the material's conductive properties, will cause changes in the induced magnetic field. These changes, when detected, indicate the presence of change in the test object.
  20. 20. RadiographicTesting <ul><li>Radiography </li></ul><ul><li>Involves the use of penetrating gamma or X‑radiation to examine parts andproducts for imperfections. </li></ul><ul><li>An X‑ray machine or radioactive isotope is used as a source of radiation. Radiation is directed through a part and ontofilm or other media. </li></ul><ul><li>The resulting shadowgraph shows the internal soundnessof the part. Possible imperfections are indicated as density changes inthe film in the same manner as an X‑ray shows broken bones. </li></ul>
  21. 21. Acoustic Emissions Testing Acoustic Emission When a solid material is stressed, imperfections within the material emit short bursts of acoustic energy called “emissions”. As in ultrasonic testing, acoustic emissions can be detected by special receivers. Emission sources can be evaluated through the study of their intensity, rate and location.
  22. 22. Visual Testing <ul><li>Visual and Optical Testing </li></ul><ul><li>Visual examiners follow procedures that range from simple to very complex. </li></ul><ul><li>Some procedures involve comparison of workmanship samples with production parts. </li></ul>
  23. 23. Visual Testing <ul><li>Mini TV </li></ul>
  24. 24. Visual Testing <ul><li>Glasses mounted Monitor </li></ul>
  25. 25. Special NDT Methods <ul><li>NDT engineers and technicians also use magnetic resonance imaging, vibration </li></ul><ul><li>monitoring, laser ultrasonics, holography and many other specialized methods. </li></ul>