Level II Questions Magnetic Particle Testing Method Flashcards
- The interpretation of magnetic particle
indications may be aided by:
a. observing with a magnifying glass.
b. reproducing the indication after
demagnetization.
c. observing the indications after the part is
pre-cleaned.
d. observing the indications after the part is
post-cleaned.
a. observing with a magnifying glass.
- Residual magnetism may be beneficial as an aid:
a. in demagnetization.
b. in proper heat treating.
c. in the deposition of weld metal.
d. in interpretation and evaluation of indications
d. in interpretation and evaluation of indications
- An interruption in the normal physical structure
or configuration of a part which produces a
magnetic particle testing indication is called:
a. a defect.
b. an indication.
c. a deformation.
d. a discontinuity.
d. a discontinuity.
- Comparing parts that have been circularly
magnetized and those that have been
longitudinally magnetized, which retain the most
objectionable residual field if not demagnetized?
a. circular
b. vectored
c. remnant
d. longitudinal
d. longitudinal
- What type of magnetization uses the formula:
Ampere turns = 45 000/(L/D)?
a. circular
b. parallel
c. vectored
d. longitudinal
d. longitudinal
- Why are large soft contact pads such as lead or
copper braid used for surfaces or headstocks?
a. To increase the contact area and reduce the
possibility of burning the part.
b. Because they help heat metal, thus facilitating
magnetic induction.
c. To increase the contact area and flux density.
d. Because of their low melting points.
a. To increase the contact area and reduce the
possibility of burning the part.
- A rough forging that has received no further
processing is magnetic particle tested. An
indication is observed to run in every direction
and appears to extend deeply into the part and
perpendicular to the surface. It is very sharp.
What is the probable identity of the indication?
a. forging burst
b. flake
c. seam
d. lap
a. forging burst
- A gear with case-hardened ground teeth and hub
ends is magnetic particle tested. Individual
indications are detected on five teeth and one end
surface of the hub. The indications do not break
over the part edges. What is the probable identity
of the indication?
a. grinding cracks
b. quench cracks
c. inclusions
d. porosity
a. grinding cracks
- If an overall pattern (sometimes circular lines)
appears on the test surfaces, how should the
inspector reprocess the test piece?
a. Demagnetize the piece.
b. Retest at a higher amperage.
c. Retest at lower amperage.
d. Part is not testable
c. Retest at lower amperage.
- A prime consideration when selecting a powder
to be used as a magnetic particle medium is to
select a powder that:
a. will adhere to the surface being tested.
b. provides a low contrast to the surface being
tested.
c. provides a high contrast to the surface being
tested.
d. quires a high demagnetization current to
remove it.
c. provides a high contrast to the surface being
tested.
- When testing for fine shallow surface cracks, the
preferred magnetic particle test method should
be:
a dry alternating current.
b. dry direct current.
c. wet alternating current.
d. wet direct current.
c. wet alternating current.
- Which of the following is an advantage of the
dry method over the wet method?
a. It is more sensitive to fine surface cracks.
b. It is easier to use for field inspection with
portable equipment.
c. It is faster than the wet method when testing a
number of small parts.
d. It is more capable of providing full surface
coverage on irregularly shaped parts.
b. It is easier to use for field inspection with
portable equipment.
- When testing a bar with a length-to-diameter
ratio of 4 in a 10-m coil, the required current
would be:
a. 45 000A.
b. 18 000A.
c. 1125A.
d. Unknown, more information is needed.
c. 1125A.
- Internal splines and holes drilled parallel to, or
near, test surfaces will cause:
a. sharp, well-defined indications directly
aligned with the part’s internal contours.
b. broad, fuzzy indications directly aligned with
the pan’s internal contours.
c. distinct indications not aligned with any
internal contours.
d. no indications.
b. broad, fuzzy indications directly aligned with
the pan’s internal contours.
- A limitation of coil magnetization techniques is
that:
a. regardless of part size, the part cannot be
painted.
b. the coil must be of maximum diameter in
relation to part.
c. the effective field is generally limited on
either side of the coil.
d. small diameter parts must be placed close to
the center of the coil.
c. the effective field is generally limited on
either side of the coil.
- Which of the following wave patterns depicts the
wave form of three-phase full-wave rectified
alternating current?
a
- Which of the following casting discontinuities is
caused by nonuniform cooling resulting in
stresses that rupture the surface of the metal?
a. hot tears
h. porosity
c. dross
d. shrinkage
a. hot tears
- The term used to refer to the total opposition to
flow of current represented by the combined
effect of resistance, inductance and capacitance
of a circuit is:
a. inductive reactance.
b. impedance.
c. reluctance.
d. decay.
b. impedance.
- A 3500 ampere-turn coil shot is required to be
performed in a 5-turn coil after a head shot of
800 A using the wet continuous method. In order
to properly conduct the coil shot it is necessary
to:
a. demagnetize the part between the head and
first coil shot.
b. check the part for residual magnetism with a
field indicator.
c. remove all residual wet magnetic particle fluid
from the part using clean, dry absorbent rags.
d. place the part in the coil and continue the
inspection after evaluating the head shot
indications.
d. place the part in the coil and continue the
inspection after evaluating the head shot
indications.
- When adding concentrate in paste form to any
wet magnetic particle suspension liquid, it is
common practice to:
a. add the paste directly to the suspension liquid.
b. change the entire bath after thoroughly
cleaning the system.
c. make a small, slurry-like test mixture of paste
and suspension and add directly to the bath.
d. mix paste in a small container with suspension
to the required bath strength and add directly
to the bath.
c. make a small, slurry-like test mixture of paste
and suspension and add directly to the bath.
- A desirable property of magnetic particles used
for either the dry or wet method is that they:
a. be toxic.
b. be nonferromagnetic.
c. possess high retentivity.
d. possess high permeability.
d. possess high permeability.
- Which of the following can cause nonrelevant
magnetic particle indications?
a. joints between dissimilar metals
b. thread cracks
c. scratches
d. bum
a. joints between dissimilar metals
- External poles which are too strong to permit
good inspection of a part are more Likely to result
when using:
a. longitudinal magnetization.
b. polarized magnetization.
c. residual magnetization.
d. circular magnetization.
a. longitudinal magnetization.
- A rough forging discontinuity has the following
characteristics: can occur on surface or internally,
is associated with low temperature processing, is
often caused by excessive working and creates
cavities varying in size. How would it be ‘
identified?
a. pipe
b. burst
c. shrinkage
d. lamination
b. burst
- Discontinuities in plate, sheet or strip caused by
internal fissures, inclusions or blowholes in the
original ingot which, after rolling, are usually flat
and parallel to the outside surface are called:
a. laps.
b. seams.
c. cracks.
d. laminations.
d. laminations.
- Forging laps occur in what relation to the axial
direction of a part?
a. They are always found on thermal centerline.
b. They are found on the surface of a part at a
90-degree angle to the long axis.
c. They may occur anywhere in the part and
always run in the direction of working.
d. They may occur anywhere on the surface and
may bear no relation to the axial direction of
the part.
d. They may occur anywhere on the surface and
may bear no relation to the axial direction of
the part.
- The accumulation of particles at a site on the part
surface, collected at and held to the site by the
magnetic leakage field, is called:
a. a defect.
b. an indication.
c. a discontinuity.
d. magnetic writing.
b. an indication.
- Where particles are attracted to a site on the
surface of a part by a magnetic leakage field that
is caused by a condition such as a crack, lap, or
other condition not acceptable to the applicable
standards for the part, then we have:
a. a defect.
b. an indication.
c. a discontinuity.
d. a nonrelevant indication.
a. a defect.
- Half-wave rectified alternating current is used for
detection of:
a. surface defects only.
b. subsurface defects only.
c. surface and subsurface defects when using dry
particles.
d. surface and subsurface defects when using wet
particles.
c. surface and subsurface defects when using dry
particles.
- Which of the following is an acceptable
technique for removing a thin film of oil or
grease prior to magnetic particle testing?
a. Wash with a solvent.
b. Degrease using a sand-blasting method.
c. Brush the surface with power wire brush.
d. Coat the surface with a thick layer of chalk
and then wipe with cloth
a. Wash with a solvent.
- Which of the following is the most common current method used for preserving and documenting
magnetic particle indications?
a. hand drawn sketch
b. color-tinted tape
c. color-tinted lacquer
d. digital photography
d. digital photography
- Which of the following is not a discontinuity
common to rolled products?
a. seams
b. cracks
c. cold shuts
d. laminations
c. cold shuts
- Which one of the following is not a discontinuity
that can be produced by the forging process?
a. laps
b. bursts
c. flakes
d. shrinkage
d. shrinkage
- Which of the following is a discontinuity
commonly associated with the welding process?
a. flakes
b. seams
c. laminations
d. lack of penetration
d. lack of penetration
- Which of these cracks may appear as an
irregular, checked or scattered pattern of fine
lines usually caused by local overheating?
a. corrosion
b. crater cracks
c. fatigue cracks
d. grinding cracks
d. grinding cracks
- Of the following discontinuity categories, which
one is considered most detrimental to the service
life of an item?
a. corrosion
b. subsurface inclusions
c. cracks open to the surface
d. subsurface porosity and voids
c. cracks open to the surface
- If 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. less than in the conductor.
b. greater than in the conductor.
c. the same intensity and pattern as in the
conductor.
d. the same regardless of its proximity to the
cylinder wall.
b. greater than in the conductor.
- The length of a part being magnetized by passing
an electric current from one end to the other:
a. causes the magnetic field to vary.
b. affects the permeability of the part.
c. changes the strength of the magnetic field.
d. does not affect the strength of the magnetic
field.
d. does not affect the strength of the magnetic
field.
- If 25 mm (I in.) and 51 mm (2 in.) diameter bars
of the same material were magnetized by passing
the same current through them, the magnetic
fields would be:
a. the same for both.
b. stronger in the 5 1 mm (2 in.) diameter bar.
c. weaker in the 25 mm (1 in.) diameter bar.
d. stronger in the 25 mm (1 in.) diameter bar.
d. stronger in the 25 mm (1 in.) diameter bar.
- If a current of the same amperage is passed through two conductors of the same dimensions, one of which is magnetic and one of which is nonmagnetic, the magnetic field distribution surrounding the conductors will:
a. vary with the permeability.
b. be the same for both conductors.
c. be stronger for the magnetic conductor.
d. be stronger for the nonmagnetic conductor
b. be the same for both conductors.
- The most effective magnetic particle test method
for inspection of a large casting is using:
a. a tend conductor.
b. direct magnetization.
c. multidirectional magnetization.
d. prod inspection in two directions.
c. multidirectional magnetization.
- The most common failure mechanism associated
with in-service parts with sharp fillets, notches,
undercuts and seams is:
a. shrinkage.
b. crystallization.
c. Decarburization.
d. fatigue cracking.
d. fatigue cracking.
- When it is believed that a discontinuity has been removed by a grinding operation, the next operation is to:
a. repair it
b. sign off inspection of the part.
c. measure it to see if minimum thickness remains.
d. re-examine the area by magnetic particle testing.
d. re-examine the area by magnetic particle testing.
When the most complete demagnetization available is desired and demagnetization is to be accomplished by placing the part in a coil energized with alternating current of progressively decreasing amperage, the following orientation of the long axis of the part is most desirable:
a. east-west.
b. north-east.
c. south-west.
d. north-south.
a. east-west.
- During a magnetic particle test, nonrelevant
indications due to residual local poles are noted
to be interfering with the magnetic particle
testing. For a successful examination one should:
a use more amperage.
b. use lower amperage.
c. magnetize in another direction.
d. demagnetize then remagnetize in the desired
direction.
d. demagnetize then remagnetize in the desired
direction.
- Cold working indications will not reappear if the
part is:
a. demagnetized then retested.
b. retested after stress relieving.
c. retested the opposite direction.
d. remagnetized at a higher amperage.
b. retested after stress relieving.
- The unit of measure of one line of flux per
square centimeter of area is one:
a. ohm.
b. gauss.
c. ampere.
d. Oersted.
b. gauss.
- The ability of matter to attract other matter to
itself is a phenomenon associated with:
a. magnetism.
b. field strength.
c. pole strength.
d. coercive force
a. magnetism.
- Materials which are strongly attracted to a magnet are called:
a. polarized.
b. magnetized.
c. nonmagnetic.
d. ferromagnetic
d. ferromagnetic
- Materials which are weakly attracted
magnetically are called:
a. diamagnetic.
b. nonmagnetic.
c. paramagnetic.
d. ferromagnetic
c. paramagnetic.
- Materials which are repelled magnetically are called:
a. diamagnetic.
b. nonmagnetic.
c. paramagnetic.
d. ferromagnetic.
a. diamagnetic.
- The end of a magnet at which the lines of flux are thought of as entering the bar is the:
a. north pole.
b. south pole.
c. positive pole.
d. negative pole.
b. south pole.
- A general rule to use for determining the
detectability of surface discontinuities by
magnetic particle inspection is that:
a. the depth and width have no bearing to each
other.
b. the depth should be at a one-to-one ratio to the
width.
c. the depth should be 20% of the material
thickness.
d. the depth should be at least five times the
width of the opening of the discontinuity at
the surface.
d. the depth should be at least five times the
width of the opening of the discontinuity at
the surface.
- The general term used to refer to a break in the metallic continuity of the part being tested is:
a. discontinuity
b. crack.
C. seam.
d. lap
a. discontinuity
- The pattern of iron powder sprinkled on a paper
placed over a bar magnet is called a:
a. flux meter.
b. field survey.
c. magnetometer.
d. magnetograph.
d. magnetograph.
- The lines of force that form a path around a crack in a ring magnet are called:
a. flux leakage
b. field strength
c. magnetic lines
d. longitudinal field
a. flux leakage
- Since the magnetic lines of force within a bar magnet run the length of the bar, it is said to be:
a. randomly magnetized.
b. circularly magnetized.
c. permanently magnetized.
d. longitudinally magnetized.
d. longitudinally magnetized.
- Lines of flux are thought to leave a magnet at
the:
a. north pole.
b. south pole.
c. positive pole
d. negative pole.
a. north pole.
- A break in the magnetic uniformity of a part that
is called a magnetic discontinuity is related to a
sudden change in:
a. resistivity.
b. inductance.
c. permeability.
d. capacitance.
c. permeability.
- In order to detect defects in different directions in
a material by magnetic particle inspection, it is
best to use:
a. only one field.
b. other probe locations.
c. a high frequency field.
d. two or more fields in different directions
d. two or more fields in different directions
- The parts are blanks cut from rolled iron bar
stock and have been rough machined. Inspection
by continuous method reveals distinct but broken
lines parallel (6.35 mm to 25 mm) (0.25 in. to
1 in.) with the axis on some of the pieces. These
indications are indicative of:
a. shrinkage.
b. nonmetallic inclusions.
c. surface checking.
d. machining tears.
b. nonmetallic inclusions.
- A large forging is repaired by welding. Magnetic particle inspection of the repair weld reveals a sharp irregular indication running parallel with
the weld passes. It is located near the center of the bead and starts and ends by tuning off
slightly from the axial direction. This indication
is indicative of:
a. inclusions.
b. crater cracks.
c. surface checking.
d. weld shrinkage cracks.
d. weld shrinkage cracks.
- The wattage most commonly used for mercury
vapor bulbs for portable fluorescent magnetic
particle inspection is:
a. 50 watts
b. 75 watts
c. 100 watts
d. 200 watts
c. 100 watts
- An example of a nonelevant indication that would be classed as a magnetic discontinuity
rather than an actual discontinuity could be
caused by:
a corrosion.
b. a slag pocket.
c. grinding cracks.
d. a known abrupt change in the hardness of the Part.
d. a known abrupt change in the hardness of the Part.
- The detection of deep-lying internal defects in heavy steel weldments at a depth of 6.35 mm
(0.25 in.) to 51 mm (2 in.) below surface is:
a. very improbable.
b. very similar to the detection of surface cracks.
c. simple if the defect’s width can be approximated.
d. not difficult if the defect is attributable to fine porosity.
a. very improbable.
- In magnetic particle inspection, it is best to:
a. make sure that parts meet specified acceptance
criteria.
b. reinspect all questionable discontinuities to
ensure that no defective parts are accepted.
c.reinspect questionable parts utilizing another
nondestructive test method.
d. make certain that parts are better than
specified and contain no discontinuities at all.
a. make sure that parts meet specified acceptance
criteria.
- Subjecting a magnetized object to a magnetic
force that is continually reversing its direction
and gradually decreasing in intensity is know as:
a. magnetization.
b. continuous method.
c. residual method.
d. demagnetization method.
d. demagnetization method.
- Any of these welding processes is susceptible to
a discontinuity known as slag inclusion except:
a. flux cored arc welding
b. submerged arc welding
c: gas tungsten arc welding
d. shielded metal arc welding
c: gas tungsten arc welding
- Which of the following induces a longitudinal
magnetic field?
a. prod
b. yoke
c. head shot
d. internal conductor
b. yoke
- At the curie point, steel is temporarily
transformed from:
a. paramagnetic to diamagnetic.
b. ferromagnetic to diamagnetic.
c. paramagnetic to ferromagnetic.
d. ferromagnetic to paramagnetic.
d. ferromagnetic to paramagnetic.
- Magnetic field strength is measured in:
a. tesla.
b. gauss.
c. webers/m2
d. ampere/meter
d. ampere/meter
- The following types of discontinuities can be
found in an object’s subsurface except:
a. pipe.
b. hot tears.
c. cold shut.
d. segregation
b. hot tears.
- Which one of following materials has
permeability much greater than that of air?
a. permeability material
b. diamagnetic material
c. material
d. ferromagnetic material
d. ferromagnetic material
- As a magnet, the Earth is surrounded by
magnetic lines of force. These lines of force
make up what is sometimes called Earth field
and they can cause problems in both magnetizing
and demagnetizing. However Earth field is weak
in the order of:
a. 0.3 gauss
b. 0.03 gauss
c. 0.003 gauss
d. 3.0 gauss
a. 0.3 gauss
- A hysteresis curve describes the relation
between:
a. magnetizing force and flux density.
b. magnetizing force and applied current.
c. strength of magnetism and alignment of
domains within material.
d. magnetic flux density and current generated.
a. magnetizing force and flux density.
Demagnetization would most likely be required when:
a. the material has low retentivity.
b. the object is to be electric arc welded.
c. the material has low reluctance.
d. heat treatment is to be carried out after testing.
b. the object is to be electric arc welded.
- One of the disadvantages of half-wave magnetization is, when demagnetizing:
a. the current has skin effect.
b. the current does not reverse.
c. the current passes very deep.
d. the current passes only on the surface.
b. the current does not reverse.
- One disadvantage of using a single-phase
magnetic particle unit at current input values
over 600 A, in comparison with a three-phase unit is, the single-phase unit will:
a. detect only surface discontinuities.
b. not detect subsurface discontinuities.
c. require 1.73 times more input current.
d. require 1.73 times less input current.
c. require 1.73 times more input current.
- In longitudinal magnetization of a round bar, residual magnetism will be:
a. greatest at the center of bar.
b. greatest at the ends of the bar.
c. the same all over on the bar.
d. the minimum at the ends.
b. greatest at the ends of the bar.
- Magnetic particles of varying size are used for dry powder and wet methods. Typically, particle sizes for wet method testing range from:
a. 1 to 5 micrometer.
b. 1 to 25 micrometer.
c. 100 to 500 micrometer.
d. 100 to 1000 micrometer.
b. 1 to 25 micrometer.
- Yokes of solid steel have been used for many years to indicate transverse cracks. Alternating current yokes are assembled from laminated
transformer sheet to reduce:
a. the size of the yoke.
b. production costs.
c. the weight of the yoke.
d. eddy current losses.
d. eddy current losses.
