MT QB

MT LEVEL III QB G VIETNAM MAGNETIC PARTICLE TESTING – LEVEL III GENERAL – QUESTIONAIRE 1. Materials which are repelled magnetically are called a. Ferro magnetic b. Para magnetic c. Dia magnetic d. Non-magnetic 2. A single articulated yoke could be used for a. Longitudinal magnetization b. Circular magnetization c. Vector magnetization d. Parallel magnetization 3. Longitudinal magnetic field could be induced in a part by using a. Coil b. Permanent magnet c. Yoke d. All the above e. Only a & c 4. During Pre cleaning before Magnetic Particle Testing one should remove a. Loose scale or Dirt b. Grease or Water c. Tight Scale d. All the above e. a & b only 5. Which of the following currents show more skin effect? a. 60 HZ, AC b. 50 HZ, AC c. 60 HZ, HWDC d. Either a or c 6. The length of a part being magnetized by passing an electric current from one end of the other a. Would change the Permeability of the test specimen b. Affect the strength of magnetic field. c. Does not affect the strength of the magnetic field d. Adverse effects would be noticed.

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7. Of the following, the best type of current for the detection of fatigue cracks is a. Half wave direct current b. Direct current c. Alternating current d. Half wave alternating current 8. If one inch and two inch diameter bars were magnetized by passing the same current through them, the magnetic fields would be a. The same on the both b. Stronger in the two inch diameter bar c. Weaker in the one inch diameter bar d. Stronger in the one inch diameter bar 9. A circular field may be induced into a specimen by which of the following methods a. Direct Induction (Head Shot) b. Central Conductor c. Direct Induction (PROD) d. All of the above e. a&c 10. Curie point of a metal is a. Melting point of the metal b. Temperature at which heat treatment can be carried out c. Temperature above which metal looses magnetic properties d. Temperature used for Magnetic Particle Testing in wet method 11. A hard steel has a. Low reluctance b. Low permeability c. Low residual magnetism d. Low retentivity e. All of the above 12. Which of the following can be tested by MPI? a. Ferritic Steel b. Marternsitic Steel c. Austenitic Steel d. a&b e. b&c 13. Magnetic powder should have a. High retentivity b. High permeability c. High density d. b&c 2

14. The maximum visible light level permitted during fluorescent particle inspection is a. 50µw/cm2 b. 20 lux c. 20µw/cm2 d. 1000 lux 15. Coercive force is the force a. With which one magnet attract another magnet b. Produces by a cored coil c. Required to reduce residual magnetic field to zero d. Remaining in the core of a hollow part 16. When DC current is passed through an alloy Steel rod, after stopping the flow of current the rod would a. Become a permanent magnet b. Have no residual magnetic field c. Have several internal poles d. Any of the above e. None of the above 17. The ideal magnetic method for inspecting the large number of heavy castings in a short time would be a. By longitudinal magnetization b. By circular magnetization c. By both methods d. Multi-directional 18. The accumulation of particles at a site on the part surface, collected at and held to the site by the magnetic field is called a. A discontinuity b. A defect c. An indication d. Magnetic writing 19. Half wave rectified AC (HWDC) is used for detection of a. Surface defects only b. Subsurface defects only c. Surface and subsurface defects d. All of the above 20. Pie gauge is used for finding out a. A magnetic field strength b. Direction of the magnetic field c. Measuring the concentration of wet bath d. Either a or b

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21. The flux density of the magnetization induced by a coil is affected by a. The coil size b. The current in the coil c. Number of turns in the coil d. All of the above 22. How many turns of a coil will be needed to establish a longitudinal field in a steel shaft that is 9 inches long and 3 inches diameter with a magnetizing current of 3000 AMPS? a. 2 b. 3 c. 5 d. 7 23. The residual magnetization in a ferro magnetic part will be depended upon a. Type of current used b. Amperage of the current used c. Heat treatment of the part d. All of the above 24. During the test using wet powder and AC current the powder should be applied? a. Just before magnetization b. During magnetization c. Just after magnetization d. Any of the above e. A&B 25. Which of the following statement is true? a. A defect is an acceptable discontinuity b. Discontinuity is an acceptable defect c. Defect is an unacceptable discontinuity d. All defects are discontinuities e. Both c & d 26. External poles which are too strong to permit good inspection of a part or more likely to result when using a. Longitudinal magnetization b. Circular magnetization c. Polarized magnetization d. Residual magnetization

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27. When a copper conductor is placed through a ferrous cylinder and a current is passed through the conductor, then the magnetic field (Flux density) in the cylinder will be? a. The same intensity and pattern as in the conductor b. Greater than in the conductor c. Less then in the conductor d. The same regardless of its proximity to the cylinder wall 28. Non-relevant indication due to residual local poles interferes with magnetic particle testing. For a successful examination one should a. Use more amperage b. Demagnetize then re-magnetize in the desired direction c. Use lower amperage d. Magnetize in another direction 29. The unit of measure of one line of flux per square centimeter of area is one a. Orested b. Ohm c. Gauss d. Ampere 30. The temperature range for wet method? a. 0º to 28º C b. 0º to 38º C c. 5º to 40º C d. 15º to 52º C 31. A part could be demagnetized by a. Heating the part above curie point b. Using an AC coil with slowly reducing current c. Using a DC coil with step down voltage and reversing current d. All of the above 32. Which type of magnetic field induced in the ring, in fig.2?

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a. b. c. d.

Circular magnetic field Longitudinal field Vector field Polar field

33. Slender loop in fig. 1A represents

a. b. c. d.

Ferro magnetic material Para magnetic material Dia magnetic material Both a & b

34. In above fig. 1A ‘o b’ represents a. Opposite polarity b. Same polarity c. Residual magnetism d. Cohesive force

Current

35. Fig. 3 represents +

D Figure 3 a. b. c. d.

Time

AC to DC DC to AC FWDC HWDC

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36. Fig. 4 represents a weld ; 3 types of defects noted on the weld, out of them, Q shows the defect of

a. b. c. d.

Slag inclusion Group pores Crater crack Lack of fusion

37. Fig. 5 gives a ferro magnetic component of different sizes, as 1,2,3. The sequence of magnetization of the above part is

a. b. c. d.

2,1,3 1,3,2 1,2,3 2,1,3,1

38. Fig. 6 represents

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a. b. c. d.

Mill gauge Magnetometer Pie gauge Hexagonal indicator

39. The fig. 7 indicates magnetic field distribution on a conductor carrying DC. The conductor is

a. b. c. d. e.

Hollow magnetic conductor Solid non-magnetic conductor Hollow non- magnetic conductor Solid magnetic conductor None of the above

40. The fig. 8A indicates

a. b. c. d.

Un magnetized specimen Non conductor Dia - magnetic specimen Magnetized specimen

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41. The maximum visible light level permitted during fluorescent particle inspection is : a. 50 µw/cm2. b. 2 foot candle c. 20 µw/cm2. d. 1000 foot candle ANSWER Q.42 & Q.43 BASED ON FIGURE 5

42. The virgine curve is shown by line segment : a. F A. b. B A. c. O A. d. A D. 43. Magnetic saturation will occur at : a. POINT B OR E. b. POINT C OR F. c. POINT A OR D. d. None of the above. 44. If a part of 6” ø was magnetized by ac, it could be demagnetized by : a. AC. b. HWDC. c. DC. d. Any of the above.

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45. The pie gauge is to be used : a. With copper side down. b. With copper side up. c. Without copper side. d. Aluminium side down.

46. If 3 parts are to be demagnetized at one time in coil best configuration would be (figure 7):

1 a. b. c. d.

2

FIG -7

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1. 2. 3. ALL PARTS SHOULD BE DEMAGNETIZED ONE AT ATIME.

ANSWER Q.3 & Q.4 BASED ON FIGURE 1

PROD X 1 3 2

4 X

PROD

FIG 1

47. Part is being inspected by prod method. (Figure 1) which defects are likely to give best indications? a. 2,3,4. b. 1. 10

c. d.

1,4. 1,3.

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48. The same part is now magnetized by placing yoke in prod positions. Which defects would give best indications now? a. 2,3,4. b. 1,3,4. c. 2, d. 1,4. ANSWER Question 49 , 50 & 51 BASED ON FIGURE 2 1

FIG - 2

4

2 3

5 CONTROL CONDUCTOR

49. When magnetizing the part as shown in coil method which defects are most likely to be detected? a. 1,3,5. b. 2,4. c. 4.3,2 d. 4,5. e. Both b & d 50. When testing the same part by head shot which defects are likely to be seen? a. 1,3,4. b. 1, c. 1,3,. d. 1,2,3. 51. When testing the part in (figure 2) by central conductor method which defects are most likely to be defected? a. 2, b. 3,4. c. 1,4. d. 1,2,3. e. None 12

52. A part of ID=1/2” & OD = 2” was magnetized by 200 amps, HWDC, head shot. Surface field was measure to be 60 oe. If a part of similar material but ID = 2” and OD = 6” was magnetized using 1” ø copper rod , 200 amps HWDC, central conductor method, the field on the OD surface is likely to be : (ref fig 2) a. 60 Oe. b. 20 Oe. c. 180 Oe. d. CANNOT BE CALCULATED. ANSWER Q.10 & Q.13 BASED ON FIGURE 3 B

FIG- 3

10 000 8000 6000 4000 2000 1000 500 O

10

20

30

40

50

60

70

80

(oe)

53. In the above example, if the part being magnetized has a B/H curve as shown, what is the induced field in the material OD, ( i.e. at 6” od)? a. 500 GAUSS. b. 1000 GAUSS. c. 2000 GAUSS. d. 4000 GAUSS. 54. What would be the induced field on the material id? (at 2”) Ref fig 3 a. 500 GAUSS. b. 2000 GAUSS. c. 4000 GAUSS. d. 7000 GAUSS. 55. After an MPI test post cleaning of a part that is irregular shaped and made of soft steel can be especially difficult because a. of demagnetization being incomplete b. the particles used are very hard and imbed themselves into the part c. particle dyes tend to run and discolour the piece 13

d.

the carrier fluid is not emulsifiable 56. Killed steel is steel that has been a. demagnetized b. D.C. magnetized c. deoxidized d. quenched in oil 57. When a specimen cannot be placed in a fixed coil on a bench unit, a flexible cable can be wound around the piece and the two ends connected to the respective poles of the bench unit. The cable is sometimes called a. extension cable b. wander cable c. remote field cable d. jumper cable 58. The MPI technique utilizing magnetic particles in a highly viscous vehicle is termed the ________ technique. a. wet slurry b. slow vehicle c. sticky d. treacle 59. The intensity of backlights irradiance (µW/cm²) from a 400W flood lamp mercury arc lamp as compared to a 100W spot mercury arc lamp (both with plain filter) as measured at the beam centre at the same axial distance is a. 16 times greater b. 4 times greater c. 1/2 the intensity d. 1/10 the intensity 60. For underwater MPI it has been found that the A.C. yoke can be used in the "single leg" technique. The magnetic field produced for this is a. longitudinal b. circular c. radial d. swinging

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Identify the Mag fields

A

B

C

D

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E 61. Fig A represents a. Field distribution around solid non magnetic conductor with DC b. Field distribution around hollow non magnetic conductor with DC c. Field distribution around solid magnetic conductor with DC d. Field distribution around hollow magnetic conductor with AC e. Field distribution around hollow magnetic conductor with central conductor with DC 62. Fig B represents a. Field distribution around solid non magnetic conductor with DC b. Field distribution around hollow non magnetic conductor with DC c. Field distribution around solid magnetic conductor with DC d. Field distribution around hollow magnetic conductor with AC e. Field distribution around hollow magnetic conductor with central conductor with DC 63. Fig C represents a. Field distribution around solid non magnetic conductor with DC b. Field distribution around hollow non magnetic conductor with DC c. Field distribution around solid magnetic conductor with DC d. Field distribution around hollow magnetic conductor with AC e. Field distribution around hollow magnetic conductor with central conductor with DC

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64. Fig D represents a. Field distribution around solid non magnetic conductor with DC b. Field distribution around hollow non magnetic conductor with DC c. Field distribution around solid magnetic conductor with AC d. Field distribution around hollow magnetic conductor with AC e. Field distribution around hollow magnetic conductor with central conductor with DC 65. Fig E represents a. Field distribution around solid non magnetic conductor with DC b. Field distribution around hollow non magnetic conductor with DC c. Field distribution around solid magnetic conductor with DC d. Field distribution around hollow magnetic conductor with AC e. Field distribution around hollow magnetic conductor with central conductor with DC

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MT QB LEVEL III VIETNAM ANSWERS Q.NO. AND Q.NO. ANS Q.NO. ANS Q.NO. ANS 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

C A D E A C C D D C B D B B C D D C C B

21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

D C D B E A B B C D D B A C D A C C B D

41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

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B C D D B B B C E C E A A D A C B A A C

61 62 63 64 65

A B E C D