NDE TEST 3 UPDATED ACTUAL QUESTIONS AND
CORRECT ANSWERS
Question:
1. What type of material can magnetic particle inspection be used on?
Answer:
Ferromagnetic
Question:
2. What does the word ferromagnetic mean?
Answer:
Iron, Nickel, Steel (Magnetized)
- It can be magnetized
Question:
3. What 2 terms are used to describe the magnetic field?
Answer:
- Lines of force
- Flux lines
Question:
4. Why is the orientation of the crack so critical for a complete inspection?
Answer:
Longitudinal crack will not show, 45 will show, but 90 degrees is best
Direction of flux lines/lines of force critical for detection of faults. 90 degrees is best, parallel wont be
detected.
Question:
5. Direct induction in a "head shot" induces what kind of field?
Answer:
Circular Field
Question:
6. Indirect induction in a "coil shot" induces what kind of field?
Answer:
Longitudinal Field
Question:
7. When using the "residual magnetism process" when are the magnetic particles applied?
Answer:
After the part has been magnetized (Magnetize then put on particles)
Question:
8. What are the advantages of MPI?
, Answer:
- Portability
- Fine and shallow
- Fast and simple
- Can work through a coating of paint (has to be a specific thickness)
- Generally inexpensive
- few limits on shape and size
Question:
9. What are the disadvantages of MPI?
Answer:
- Has to be ferromagnetic
- Orientation and strength of field is critical (to high amperage will blur the line)
- Surface and near surface only
- Part must be demagnetized
- Can burn parts
Question:
10. What principle is eddy current based on?
Answer:
Electromagnetic Induction
Question:
11. What will reduce the conductivity of the material?
Answer:
A discontinuity or a crack, disrupts the flow of electrons
Question:
12. If there is a defect, what happens to the flow of eddy currents?
Answer:
Flow is decreased, current slows down Detects cracks perpendicular
Question:
13. How deep can eddy current detect defects?
Answer:
5mm or 0.196 in (will not find if any further)
Question:
14. What is noise during eddy current inspection?
Answer:
Background signals that are coming back
Question:
15. What causes noise?
Answer:
- Lift off
- Edge of part
CORRECT ANSWERS
Question:
1. What type of material can magnetic particle inspection be used on?
Answer:
Ferromagnetic
Question:
2. What does the word ferromagnetic mean?
Answer:
Iron, Nickel, Steel (Magnetized)
- It can be magnetized
Question:
3. What 2 terms are used to describe the magnetic field?
Answer:
- Lines of force
- Flux lines
Question:
4. Why is the orientation of the crack so critical for a complete inspection?
Answer:
Longitudinal crack will not show, 45 will show, but 90 degrees is best
Direction of flux lines/lines of force critical for detection of faults. 90 degrees is best, parallel wont be
detected.
Question:
5. Direct induction in a "head shot" induces what kind of field?
Answer:
Circular Field
Question:
6. Indirect induction in a "coil shot" induces what kind of field?
Answer:
Longitudinal Field
Question:
7. When using the "residual magnetism process" when are the magnetic particles applied?
Answer:
After the part has been magnetized (Magnetize then put on particles)
Question:
8. What are the advantages of MPI?
, Answer:
- Portability
- Fine and shallow
- Fast and simple
- Can work through a coating of paint (has to be a specific thickness)
- Generally inexpensive
- few limits on shape and size
Question:
9. What are the disadvantages of MPI?
Answer:
- Has to be ferromagnetic
- Orientation and strength of field is critical (to high amperage will blur the line)
- Surface and near surface only
- Part must be demagnetized
- Can burn parts
Question:
10. What principle is eddy current based on?
Answer:
Electromagnetic Induction
Question:
11. What will reduce the conductivity of the material?
Answer:
A discontinuity or a crack, disrupts the flow of electrons
Question:
12. If there is a defect, what happens to the flow of eddy currents?
Answer:
Flow is decreased, current slows down Detects cracks perpendicular
Question:
13. How deep can eddy current detect defects?
Answer:
5mm or 0.196 in (will not find if any further)
Question:
14. What is noise during eddy current inspection?
Answer:
Background signals that are coming back
Question:
15. What causes noise?
Answer:
- Lift off
- Edge of part
