NDT

Question 0

Liquid penetrant

Answer 0

• enters flaw through capillary action
• area around flaw needs to be cleaned at least 1” around
• widely used in leak detection in welded thin walled vessels

Question 1

Eddy current

Answer 1

• only one that needs A/C
• very good for checking surface and subsurface cracks beneath paint
• very fast & cheap
• pieces can be non-magnetic and conductive
• coil is the basic component

Question 2

Solvent removable

Answer 2

-dye penetrant used for small area of a work piece

Question 3

Fluorescent dye penetrant

Answer 3

• requires ultra violet light

- does not detect internal flaws

Question 4

Magnetic particle inspection

Answer 4

• Sprinkle workpiece with dry iron powder or submerge in a liquid with suspended iron particles
• depth of 1/4”
• electric current is used to magnetize,but regular magnets can work as well
• 90 degrees or right angles to the defect
• portable equipment

Question 5

Dwell time

Answer 5

-Time a penetrant or developer is in contact with a surface

Question 6

Discontinuity

Answer 6

-interruption in normal structure such as crack, seam, porosity

Question 7

Contrast in X-ray

Answer 7

-different degrees of darkening on the film

Question 8

Definition in X-ray

Answer 8

-sharpness the image is projected on the film

Question 9

Destructive testing

Answer 9

• tensile
• compressive
• torsion
• fatigue
• hardness
• impact

Question 10

Non-destructive

Answer 10

• visual
• dye penetrant
• magnetic particle
• ultrasonic
• radiography

Question 11

Radiography

Answer 11

• Electromagnetic energy
• Uses gamma & X-ray
• can be used for thick materials

Question 12

Ultrasonic

Answer 12

• Up to 20ft
• High frequency sound waves between 20,000 cycles per second and 10,000,000
• for longitudinal & shear waveforms

Question 13

Penetrameter

Answer 13

• Measures quality of radiography

- a plate with 3 holes in it 2% of the thickness of the specimen

Question 14

Ultrasonic sound waves

Answer 14

• Electric pulses generated from the crystals and reflects back
• highly sensitive, but rough or small pieces are hard to test

Question 15

Couplant

Answer 15

• gel, oil or water

- allows the sound beam to go from the transducer to the test piece

Question 16

Retentivity

Answer 16

-easily loses its magnetism

Question 17

Magnetic permeability

Answer 17

-easy to magnetize

Question 18

Direct current

Answer 18

• penetrate the cross section of the part

- use single or three phase with a rectifier

Question 18

Alternating current

Answer 18

• fields are confined to the metal at or near the surface of the part (skin effect)
• should not be used for subsurface discontinuities
• single phase only for magnification purposes

Question 19

Magnetized bars

Answer 19

-magnetic lines of force flow through the bar south to north

Question 20

X-ray

Answer 20

-best for checking engine or compressor cylinder heads

Question 21

Gamma rays

Answer 21

• iridium 192 .25” to 3.5”
• cobalt 60 1” to 7”
• shielding container is the camera
• container holding the material is called the source