Study Non Destructive Testing Flash Cards

 
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Non Destructive Testing

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Describe X-ray NDT:
Film is exposed to x-rays and developed. Dark areas indicate a possible defect. Does not indicate depth of defect.
Eddy current NDT can be used on what materials?
Not limited to material type. Composites are OK.
Describe Eddy Current NDT:
AC current builds up a magnetic field. A good part (baseline reference) and test part (differences) are needed for comparison. Test looks at Eddy current changes from good part to defective part.
Describe Through-transmission NDT:
A pulse is sent through the test part to a receiver on other side of part. Defects block pulse and reduces amount of energy transmitted. Training required.
Describe Pulse-echo NDT:
A pulse is sent through a part and the defect will appear via reflections, CRT indicated defects and approximate location.
Describe Resonance NDT:
Comparison technique which uses a good part to look for differences when a test part is resonated with sound.
What are the 4 sound techniques for NDT?
Tapping
Resonance
Pulse-echo
Through transmission
Magnetic Particle Inspection. Disadvantages:
Ferrous parts only.
Large machine needed.
Lots of power needed.
Expensive machine required.
Magnetic Particle Instpection. Name advantages:
Detection to 1/2 depth of surface.
Somewhat cleaner than Dye Penetrate.
Slurry types magnetic particle detection are:
Magnaglow for UV - white lines
Magnaflux - visual or daytime, red slurry with filing.
When a part is held on end for magnetic particle inspection what direction are the lines of flux and what type of crack is best detected?
Head shot - flux lines are Radial and an axial crack is easiest to detect. Think, Head, parallel lines of flux, perpendicular crack detection.
When a coil is place around a part for magnetic particle inspection what direction are the lines of flux and what type of crack is best detected?
Coil shot - flux lines are axial and a radial crack is easiest to detect. Think, Coil, straight lines of flux, perpendicular crack detection.
What are the 2 Mag Particle inspection types? What are they called this.
Coil shot - coil is place around part. Head shot - part is squeezed between two electrodes.
Describe Mag. Particle Inspection process.
Set up machine and magnetize the part. Apply slurry with iron particle that indicate problems. Demagnetize by slowly removing from AC field.
What problems can Magnetic Particle Inspection find.
Cracks and issues down to 1/2 inch under surface.
What material can Magnetic Particle Inspection be used on?
Only iron based, must be able to be magnetized.
What is Dye Penetrate used for and on what materials?
Surface issues on plastic, glass or metal. Non porous materials.
Describe Dye Penetrate process.
Apply Cleaner (Gross Clean)
Penetrate -gets in cracks.
Fine Clean - remove all but product in cracks.
Developer - Spot Check or Zyglo
Inspect
Name the Dye Penetrate methods.
Spot check for daytime visual. Zyglo for UV light use.
Describe Visual NDT.
Eye ball... use mirror, flashlight, magnifying glass.
Describe Rockwell hardness testing
Machine penetrates material and measures the depth. Returns a number for a scale referenced to kpsi. 100 Red Ball for lower kpsi scale is 0-130, 150 black Bralle for harder, scale is 0-100.
Describe Brinnel Hardness testing:
machine places a small dent in metal and then measures diameter.
Two types of Hardness testing are
1) Brinnel
2) Rockwell
Toughness is
withstands tearing, shearing and may be stretched or otherwise deformed without breaking. Hard but malleable, not brittle.
Yield point is
point at which a material does not return to original shape.
Elastic range is
range where a given piece of metal will return to its original shape.
Ductility is
ability to be drawn, bent or twisted without breaking.
Malleability is
opposite of brittle. ability to tolerate deformation without failure, hammered or rolled pressed without cracking, breaking or some other detrimental effect.
Brittleness is
inability of a material to resist bending or deformation without shattering.

Brittleness is directly proportional to hardness or strength.
Hardness is
ability to resist abrasion, penetration, cutting action or permanent distortion.

Hardness is directly proportional to strength.
Metal properties: Strength is
ability to resist stress or deformation typically measured in tensile strength or PSI
Penetration stress is
impact, short periods
Bending stress is
tension and compression.
Torsion Stress is
twisting or rotational stress.
Shear Stress is
cutting force
Compression Stress is
pushing together
Tensile Stress is
pulling apart stretching force
Define Strain
Results of Stress (applied stress)
Define Stress
Applied Force
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