L2 Flashcards
1
Q
- The magnetic domains in a permanent magnet
are aligned in:
a. fixed positions with directions that cancel out.
b. fixed positions, predominantly in one
direction.
c. the same diction as the metal’s grain
structure.
d. a random position and may become aligned to
attract a magnetic material.
A
b. fixed positions, predominantly in one
direction.
2
Q
- For which of the following would the wet
fluorescent technique be preferred over the dry
technique?
a. When the parts are large and bulky.
b. When increased speed and sensitivity are desired.
c. When the parts being inspected are to be field
welded.
d. When it is desired to use the fluorescent
lighting provided in many plants.
A
b. When increased speed and sensitivity are desired.
3
Q
- Gas, hot tears, cold shuts, shrinkage cracks and sand inclusions are examples of defects resulting from which of the following processes?
a. forging
b. grinding
c. casting
d. heat treatment
A
c. casting
4
Q
- Which of the following statements is a valid reason for demagnetizing a part after completing
a magnetic particle test?
a. Residual magnetism can disturb the welding
arc path on parts to be welded.
b. Residual magnetism may attract chips or small
particles in-service, causing galling or
mechanical wear.
c. Residual magnetism could interfere with the
operation or accuracy of instruments placed on
or near the part during service.
d. If the part is to be radiographed after magnetic
particle inspection, residual magnetism may
interfere with the electromagnetic radiation
spectrum.
A
d. If the part is to be radiographed after magnetic
particle inspection, residual magnetism may
interfere with the electromagnetic radiation spectrum.
5
Q
- Subjecting a part to a magnetic field that is
constantly reversing in polarity and gradually
diminishing in strength accomplishes which of
the following?
a. Magnetizes the part.
b. Demagnetizes the part.
c. Helps to locate deep-laying defects.
d. Increases the strength of the retained magnetic
field.
A
b. Demagnetizes the part.
6
Q
- The concentration of the solid content of a
suspension of magnetic particles is measured by:
a. weighing the suspension.
b. soaking the solids in benzol.
c. measuring the pull on a magnet.
d. permitting the solids to settle out of
suspension.
A
d. permitting the solids to settle out of
suspension.
7
Q
- An important factor that must be considered
when selecting a method of magnetization is the:
a. part’s curie point.
b. the location of the inspection station.
c. location of the inspection unit.
d. alloy, shape and condition of the part
A
d. alloy, shape and condition of the part
8
Q
- When a magnetic material reaches its curie
temperature the material becomes:
a. magnetic.
b. radioactive.
c. diamagnetic.
d. paramagnetic.
A
d. paramagnetic.
9
Q
- Magnetic particle inspection methods on
ferromagnetic materials are recognized as
superior to liquid penetrant techniques when:
a. the surface is plated.
b. the parts are painted.
c. the surface is anodized.
d. dry particles are used for fine surface cracks.
A
b. the parts are painted.
10
Q
- A paramagnetic material:
a. is highly magnetic.
b. is slightly magnetic.
c. has no magnetic properties at all.
d. has a demonstrated lack of electron mobility.
A
b. is slightly magnetic.
11
Q
- Which of the following will reduce a magnetic
field?
a. Move the direct current coil closer to the part.
b. Reduce the current in only one direction.
c. Move the alternating current coil further away
from the part.
d. Move the part toward the inner surface of the
coil
A
c. Move the alternating current coil further away
from the part.
12
Q
- When an external magnetizing force is removed,
some of the magnetic domains remain
preferentially oriented. The additional force
required to return them to their original random
orientation is commonly referred to as:
a. coercive force.
b. applied field force.
c. residual field force.
d. direct current electric force.
A
a. coercive force.
13
Q
- When a cylinder is magnetized by a central
conductor, the field is most intense:
a. at the ends of the cylinder.
b. at the outer surface of the cylinder.
c. at the inside surface of the cylinder.
d. halfway through the thickness of the cylinder
wall.
A
c. at the inside surface of the cylinder.
14
Q
- When is the magnetic field strongest in an object
being inspected by the magnetic particle method?
a. While the magnetizing current is applied.
b. Just after the magnetizing current is shut off.
c. When the magnetic particle powder is applied.
d. Just prior to current reversal when using
alternating current.
A
A
15
Q
- Which of the demagnetization methods listed
below is most effective?
a. full-wave rectified
b. half-wave rectified alternating current
c. direct current with reversing and step-down control
d. variable voltage alternating current with
step-down control
A
c. direct current with reversing and step-down control
16
Q
- When using the longitudinal magnetization
method to inspect a bar 152 mm (6 in.) long and
5 1 mm (2 in.) in diameter with a 5-turn coil,
which of the following amperage values should
be used?
a. 1200A
b. 3000A
c. 12000A
d. 2000 amp-turns
A
b. 3000A
17
Q
- To examine a part 127 mm (5 in.) long and 51
mm (2 in.) in diameter using a 5-turn coil and
head stock magnetic particle machine, what
amperage should be used for longitudinal
magnetization?
a. 3000A
b. 3600A
c. 4500 A
d. 10 000 ampere-turns
A
b. 3600A
18
Q
- To examine a bar 381 mm (15 in.) long and
5 1 mm (2 in). in diameter using a 7-turn coil and
head-stock magnetic particle machine, what
amperage should be used for circular
magnetization?
a. 750 A
b. 1800A
c. 1800 amp-turns
d. 49 000 amp-turns
A
b. 1800A
19
Q
- If the same amperage is passed through a 25 mm
and 51 mm (I in. and a 2 in.) diameter bar of the
same length and material, the strength of the
magnetic field at the surface:
a. will be the same for both bars.
b. of the 25 mm (1 in.) bar will be one-half that
of the 51 mm (2 in.) bar.
c. of the 25 mm (I in.) bar will be approximately
twice that of the 51 mm (2 in.) bar
d. of the 51 mm (2 in.) bar will be approximately
four times that of the 25 mm (1 in.) bar.
A
c. of the 25 mm (I in.) bar will be approximately
twice that of the 51 mm (2 in.) bar
20
Q
- If the same amperage is passed through a 25 mm
(1 in.) diameter bar and a 51 mm (2 in.) diameter
bar of the same length and material, the strength
of the magnetic field at the center of:
a. both bars will be 0.
b. the 25 mm (1 in.) bar will be one-half that of
the 5 1 mm (2 in.) bar.
c. the 51 mm (2 in.) bar will be one-half that of
the 25 mm (1 in.) bar.
d. the 25 mm (1 in.) bar will be approximately
one-fourth that of the 51 mm (2 in.) bar.
A
d. the 25 mm (1 in.) bar will be approximately
one-fourth that of the 51 mm (2 in.) bar.
21
Q
- When a magnetic field is induced in a part with
prods spaced 152 mm (6 in.) apart, the field is a:
a. circular field.
h. residual field.
c. solenoid field.
d. longitudinal field.
A
a. circular field.
22
Q
- When circular magnetization is used to detect subsurface discontinuities, direct current is used
instead of alternating current because:
a. particle mobility is no longer a factor.
b. there is no logical reason to use direct current
instead of alternating current.
c. direct current saturates the magnetic particles
better than alternating current.
d. the skin effect of alternating current reduces
the maximum depth at which discontinuities
can be found.
A
d. the skin effect of alternating current reduces
the maximum depth at which discontinuities
can be found.
23
Q
- An inspection method in which an initial magnetizing force is applied to a part and then reduced to a lower continuous value is called:
a. the surge method.
b. the residual method.
c. the multivector method.
d. the continuous method.
A
a. the surge method.
24
Q
- When deciding to inspect a part by the residual method of applying the particles, what factor
affects the residual magnetic field strength of the part?
a. the retentivity of the part
b. the part’s magnetic field saturation point
c. the direction of the magnetic field in the part
d. the type of field indicator used to measure the
residual field
A
a. the retentivity of the part
25
26. Factors that must be considered when
interpreting an indication are:
a. the direction of the magnetic field and location
of the magnetic particle unit.
b. the location of the magnetic particle unit and
the nondestructive testing level of the
inspector.
c. the orientation and shape of the indication and
the direction of the magnetic field.
d. the strength of the leakage field at the
indication and the type of demagnetization
method.
.
c. the orientation and shape of the indication and
the direction of the magnetic field
26
27. A 7-turn coil at 1000 A is used to inspect a round solid part 381 mm (15 in.) long and 64 mm (2.5 in.) in diameter. The length-to-diameter ratio
is:
a. 2.14.
b. 6.0.
c. 7000 amp-turns.
d. 45 000 amp-turns.
b. 6.0.
27
28. Which of the following, when used as the last magnetizing method, will best render a part
suitable for relatively easy measurement of the external magnetic field using a field indicator?
a. probe magnetization
b. circular magnetization
c. longitudinal magnetization
d. central bar conductor magnetization
c. longitudinal magnetization
28
29. When using direct current an indication is
detected. What is the next logical step to
determine if the indication results from a surface or subsurface condition?
a. Reinspect using alternating current.
b. Reinspect at higher amperage.
c. Demagnetize and apply powder.
d. Reinspect using the residual method.
a. Reinspect using alternating current.
29
30. Which of the statements below is most
appropriate concerning materials I and II
represented by the hysteresis curves shown in Figure l?
a. Material I is not a good subject for magnetic
particle inspection.
b. Material I could be used for dry powder
magnetic particles.
c. Material I1 could be used for dry powder
magnetic particles.
d. Material I1 is paramagnetic.
(PRENTJIE)
c. Material I1 could be used for dry powder
magnetic particles.
30
31. Considering the curves shown in Figure. 1, material II in comparison to material I indicates
that the material:
a. has a high retentivity.
b. has a high permeability.
c. has a high coercive force.
d. would make an excellent permanent magnet.
pRENTJIE
b. has a high permeability
31
32. Point B on the hysteresis curve for material I
shown in Figure 1:
a. is the limit of coercive force.
b. is the material’s magnetic saturation point.
c. represents the mid-point of the rectified
alternating current applied.
d. represents the point at which the residual
magnetic value will remain when the
magnetizing current is removed.
pRENTJIE
32
33. Which point on the hysteresis curve shown in Figure. 1 represents the residual field value?
a. A
b. B
c. C
d. E
c. C
33
34. When withdrawing a part from the field around a coil and without changing the direction of
current, which of the following has the least
effect on demagnetizing the part?
a. direct current
b. alternating current
c. full-wave rectified current
d. half-wave rectified alternating current
a. direct current
34
35. The least important factor below that should not be considered when selecting a
method of magnetization to detect subsurface discontinuities is:
a. available equipment
b. configuration of the part
c. cost of the equipment
d. type of materials the part is made from
c. cost of the equipment
35
36. Which of the following discontinuities occur as a
result of the rolling process?
a. fissures
b. laminations
c. lack of penetration
d. blowholes and pipe
b. laminations
36
37. Which of the following discontinuities occur as a
result of the forging process?
a. pipe
b. laps
c. laminations
d. lack of penetration.
b. lapsb. laps
37
38. If an indication is formed when using the
residual method as well as the continuous
method, it is most likely:
a. very deep and tight
b. a relevant indication.
c. a nonrelevant indication.
d. very shallow and open to the surface.
b. a relevant indication.
b. a relevant indication.
38
39. Plated parts can be reliably tested for fine surface cracks using the magnetic particle method if the plating is less than:
a. 0.762 mm (0.03 in.) thick.
b. 1.016 mm (0.04 in.) thick.
c. 0.127 mm (0.005 in.) thick.
d. 0.2032 mm (0.008 in.) thick.
c. 0.127 mm (0.005 in.) thick.
39
40. The magnetic lines of flux in a permanent magnet:
a. in all cases produce a longitudinal field
b. enter the south pole and leave through the north pole
c. flow from the north pole through the magnet to the south pole
d. change direction 60 times a second with the magnetizing current
b. enter the south pole and leave through the north pole
40
41. Which of the following magnetization techniques is not recommended for magnetic particle testing?
a. vector magnetization
b. parallel magnetization
c. circular magnetization
d. longitudinal magnetization
b. parallel magnetization
41
42. When attempting to demagnetize a part
containing a circular residual field:
a. use a swinging cyclic field.
b. consideration of the material’s hysteresis is
most important.
c. establish a longitudinal field and then proceed
with demagnetization.
d. using half-wave current with a head shot setup
and Jtep-down magnetization will ensure -
complete removal of the residual field.
c. establish a longitudinal field and then proceed
with demagnetization.
42
43. Small parts requiring demagnetization should be:
a. loaded in baskets and passed through an
alternating current coil.
b. loaded in a steel basket for better field
distribution.
c. processed through a demagnetization cycle
one at a time.
d. demagnetized after assembly to ensure
complete demagnetization of the entire
assembly.
c. processed through a demagnetization cycle
one at a time.
43
44. The best shape for magnetic particles used in the dry powder method is:
a. globular.
b. elongated.
c. long and slender.
d. a mixture of elongated and globular.
d. a mixture of elongated and globular.
44
45. The best method for testing ball bearings is:
a. along one axis using a coil.
b. two head shots along the X and Y axis.
c. two shots using a coil at the X and Y axis.
d. induced current shots along X, Y, and Z axis,
rotating 360 degrees during each shot.
d. induced current shots along X, Y, and Z axis,
rotating 360 degrees during each shot.
45
46. When a magnetized ferromagnetic object is exposed to a subsequent heating operation above the curie point:
a. the marten site structure will occur.
b. the magnetic domains become random.
c. there is no change from its previous state.
d. the magnetic domains are reversed from their
previous state
b. the magnetic domains become random.
46
47. A discontinuity caused by a welding operation is:
a. creep crack.
b. segregation.
c. machining tear.
d. lamellar tearing.
d. lameral tearing.
47
48. The most effective current to be used with dry magnetic particle is:
a. direct current.
b. half-wave rectified alternating current.
c. full-wave rectified alternating current with
three-phase bridge circuitry.
d. full-wave rectified alternating current with
single-phase bridge circuitry.
b. half-wave rectified alternating current.
48
49. The following properties should be considered in
choosing a vehicle for the wet method, except:
a capillarity.
b. corrosivity.
c. wetting ability.
d. foaming ability.
a capillarity.
49
50. The amount of light reflected by one surface
compared to that reflected by another adjacent surface is:
a. length-to-diameter ratio.
b. B/H ratio.
c. color contrast.
d. brightness contrast.
d. brightness contras
50
51. Given a certain continuous magnetization current in a material, which type of current would give the deepest penetration?
a direct current
b. altematjng current
c. direct current surge
d. half-wave direct current
d. half-wave direct current
51
52. Given a certain continuous magnetization current
in a material, which type of current would give the shallowest penetration?
a direct current
b. alternating current
c. direct current surge
d. half-wave direct current
b. alternating current
52
53. Which type of radiation can most damage human
tissue?
a UV-A
b. UV-B
c. white light
d. visible Light
b. UV-B
53
54. Compared with magnetic particle testing, liquid
penetrant testing is not reliable after paint
removal from weld because:
a. Liquid penetrant testing can be applied only to
small parts.
b. Liquid penetrant testing can be applied only in
field conditions.
c. magnetic particle testing will detect subsurface
discontinuities.
d. partial smearing of weld surface metal across
the discontinuity opening can occur.
d. partial smearing of weld surface metal across
the discontinuity opening can occur.
54
55. Prob spacing less than 76.2mm (3in.) is usually not practical because:
a. the possibiity of sparking will increase.
b. more time will be consumed for inspection.
c. it requires more media than a 152 mm (6 in.)
prod distance.
d. particles tend to bend around the prod making
interpretation difficult.
d. particles tend to bend around the prod making
interpretation difficult
55
56. One of most important facts that must be remembered while establing magnetic particle procedure.
a. Tbe magnetic field follows the path of greatest
reluctance.
b. Coil shot. wet method provides only surface
discontinuities.
c. The head shot wet method is better for
detecting subsurface discontinuities.
d. In most cases the continuous method is more
sensitive than is the residual method.
d. In most cases the continuous method is more
sensitive than is the residual method.
56
57. Which one of the following magnetic particle
testing techniques is logically acceptable for
testing a large flat area?
a. prod
b. rod shot
c. coil shot
d. head shot
a. prod
57
58. Permeability of a material can be numerically
written as:
a. RIB.
b. BM.
c. Hc/Nb.
d. ampere turn/number of turns.
b. BM.
58
59. One disadvantage for using undyed wet magnetic
particles is:
a. it is more costly.
b. it is suitable for the fluorescent method only.
c. it is suitable for surface discontinuity detection
only.
d. the lack of contrasting color makes them
difficult to see.
d. the lack of contrasting color makes them
difficult to see.
59
60. One of most desirable characteristics of the media for magnetic particle testing is:
a. the ability to show clearly against any
background.
h. the insensitiveness to concentration in water as
vehicle.
c. no need for agitation when used with liquid
vehicle.
d. the highest possible permeability and lowest
retentivity.
a. the ability to show clearly against any
background.
