MT GINZEL BRO 1-150 Flashcards
1
Q
- For demagnetizing large parts, field reversals are usually _________.
A. lower frequency than for small parts
B. higher frequency than for small parts
C. the same frequency as for small parts
D. not needed
A
A. lower frequency than for small parts
2
Q
- For best demagnetization results using a coil with A.C. and passing parts
through it you should
A. pass the part through with its long axis parallel to the coil axis
B. hold the part close to the coil
C. both a and b
D. switch the current on only when the part is centred along its length in the
coil
A
C. both a and b
3
Q
- The advantage of using reversing D.C. for demagnetization is
A. low heating effect
B. deep penetration
C. only one reversal is needed
D. all of the above
A
B. deep penetration
4
Q
- The magnetic flux in a part increases as applied field is increased. The flux
moves along the virgin curve of the hysteresis curve
A. once each cycle of applied A.C. field
B. twice each cycle of applied A.C. field
C. only once when the part is completely demagnetized
D. for paramagnetic materials only
A
C. only once when the part is completely demagnetized
5
Q
- Small parts can be demagnetized in multiple lots by passing them through an
A.C. coil provided they are
A. stacked in a basket
B. apart in single layer
C. oriented long axis parallel to coil axis
D. both b and c
A
D. both b and c
6
Q
- For rings and hollow parts a handy means of A.C. demagnetization is
A. using a yoke
B. a central conductor using decreasing current
C. surge pulses through prod contacts
D. swinging field technique
A
B. a central conductor using decreasing current
7
Q
- The most likely tool you would use to determine if a part has been adequately
demagnetized is the
A. Hall detector
B. field meter
C. electrogram
D. magnetometer
A
B. field meter
8
Q
- A problem with doing a head shot on a ball bearing is
A. arc burns damage the surface
B. no defects are found
C. the field is distorted too much
D. they cannot be demagnetized
A
A. arc burns damage the surface
9
Q
- The two classifications of media in MPI are
A. fluorescent and non-fluorescent
B. wet and dry
C. magnetic and para-magnetic
D. high temperature and low temperature
A
B. wet and dry
10
Q
- Prior to the use of magnetic particles to detect flaws by magnetic methods,
flaws could be located in iron pieces using
A. Hall detectors
B. ordinary magnetic compasses
C. electro scopes
D. electromagnetic resonance
A
B. ordinary magnetic compasses
11
Q
- The ampere is a unit of
A. electric current
B. electromotive force
C. electromagnetic force
D. magnetic intensity
A
A. electric current
12
Q
- Total current in two parallel conductors can be determined by knowing the
distance between the conductors and the
A. dielectric constant of air
B. resistivity of the conductors
C. right hand rule
D. magnetic force exerted per unit length of wire
A
D. magnetic force exerted per unit length of wire
13
Q
- The direction assigned to a magnetic dipole moment vector is determined by
A. coil size
B. conductor diameter
C. current magnitude
D. direction of current flow
A
D. direction of current flow
14
Q
- The units Webers per square metre (Wb/m^2) are used to quantify a
A. magnetic induction field
B. magnetic dipole
C. magnetic monopole
D. magnetic force
A
A. magnetic induction field
15
Q
- Magnetic field lines are
A. always concentric rings
B. symbolic only, and used to indicate spatial direction of the field
C. a result of the van Allan belts
D. of uniform density
A
B. symbolic only, and used to indicate spatial direction of the field
16
Q
- In a ferromagnetic material, a region where all the “atomic moments” are
aligned parallel to each other is called a
A. magnetic zone
B. confederation
C. domain
D. magnetic junta
A
C. domain
17
Q
- A void in an otherwise homogenous magnetized material presents itself as a
point magnetic dipole. This is the basis for
A. magnetic particle flaw detection
B. multi frequency eddy current
C. para-magnetism
D. de-magnetisation
A
A. magnetic particle flaw detection
18
Q
- Magnetic properties of materials are a result of
A. electric currents on the atomic and sub-atomic scale
B. the strong nuclear force
C. the ratio of protons to neutrons in the material
D. the weak nuclear force
A
A. electric currents on the atomic and sub-atomic scale
19
Q
- When discussing magnetization and its effects the magnetic induction field is
usually represented by the letter
A. B
B. H
C. M
D. Z
A
A. B
20
Q
- When discussing magnetization and its effects the magnetic field intensity, or
as its also called, the magnetic field is represented by the letter
A. B
B. H
C. M
D. Z
A
B. H
21
Q
- The phenomenon whereby the magnetization of a ferromagnetic sample lags the
applied cyclic magnetic field is referred to as
A. phase lag
B. Doppler effect
C. hysteresis
D. demagnetization
A
C. hysteresis
22
Q
- When a hysteresis curve is generated for a ferromagnetic material, a magnetic
field remains in the material when the applied field is returned to zero. This
field is called the
A. coercive force
B. induction field
C. residual induction
D. resultant vector
A
C. residual induction
23
Q
- The value of H applied to bring the residual value of B to zero is called
A. saturation field
B. demagnetization value
C. induction coercive force
D. phase reversal factor
A
C. induction coercive force
24
Q
- In order to be detectable by magnetic particle testing, a flaw must
A. be surface breaking
B. be no deeper than 1mm below the surface
C. produce a perturbation of the induction field at the test surface
D. all of the above
A
C. produce a perturbation of the induction field at the test surface
25
Q
- To detect a flaw by magnetic particle methods, techniques are developed to
A. maximize field perturbations in the region of a flaw
B. optimize retentivity of the material
C. propagate the flaw by Barkhausen jumps
D. all of the above
A
A. maximize field perturbations in the region of a flaw
26
Q
- Sensitivity of the magnetic particle method depends on the
A. absolute magnitude of the induced field perturbation
B. spatial gradient of the induced field perturbation
C. magnitude of the applied field
D. surface flux density of the test piece
A
B. spatial gradient of the induced field perturbation
27
Q
- Magnetic particle testing has an advantage over liquid penetrant testing
because it can
A. be used on ferromagnetic materials
B. locate surface defects
C. locate subsurface defects
D. be cheaper to use
A
C. locate subsurface defects
28
Q
- Magnetic particle testing is a practical test method to inspect.
A. glass
B. ceramics
C. aluminum castings
D. none of the above
A
D. none of the above
29
Q
- When a discontinuity causes the magnetic field lines to be forced out of the
specimen into the air, the field in the air is called a
A. force field
B. leakage field
C. flux field
D. flaw field
A
B. leakage field
30
Q
- Magnetic particles are available in many colours to
A. indicate degree of permeability
B. optimize visibility
C. indicate degree of rententivity
D. permit the inspector to choose a colour that will not clash with his/her
clothing
A
B. optimize visibility
31
Q
- Which is not an essential step in magnetic particle testing?
A. establish a suitable magnetic flux in the test piece
B. application of magnetic particles
C. examination of test piece
D. post cleaning of test piece to remove magnetic particles
A
D. post cleaning of test piece to remove magnetic particles
32
Q
- Inherent discontinuities are formed during
A. initial melting and refining of the metal
B. primary processing
C. secondary processing and manufacturing
D. in-service use
A
A. initial melting and refining of the metal
33
Q
- The deeper a subsurface defect gets below the surface
A. the greater the flux leakage it produces
B. the harder it gets to magnetize the part
C. the larger it must be to be detectable
D. all of the above
A
C. the larger it must be to be detectable
34
Q
- In order to detect a flaw by magnetic particle testing the magnetic field must
A. alternate
B. pulse
C. run parallel to the principal plane of the flaw
D. intercept the principal plane of the flaw
A
D. intercept the principal plane of the flaw
35
Q
- The cgs unit of magnetizing force (H) is the
A. oersted
B. gauss
C. tesla
D. Weber
A
A. oersted
36
Q
- The cgs unit of flux density (B) is the
A. oersted
B. gauss
C. tesla
D. Weber
A
B. gauss
37
Q
- If the ends of a long bar magnet are bent to form a circle and the ends
perfectly fused together the result will be
A. the magnet will no longer attract ferromagnetic material
B. a circular magnetic field
C. no magnetic flux leakage field
D. all of the above
A
D. all of the above
38
Q
- A bar magnet would be considered to be
A. circularly magnetized
B. longitudinally magnetized
C. electromagnetically poled
D. cross-polarized
A
B. longitudinally magnetized
39
Q
- Which of the following is not a characteristic of magnetic flux lines?
A. they attract each other
B. they form continuous loops
C. they do not cross each other
D. they decrease in intensity with distance from the surface
A
A. they attract each other
40
Q
- Inside a bar magnet magnetic flux lines are considered to flow from
A. north to south
B. south to north
C. east to west
D. west to east
A
B. south to north
41
Q
- The direction of magnetic lines of force around a current carrying conductor
is
A. parallel to the conductor
B. at right angles to the conductor
C. 45 degrees out of phase to the applied current
D. parallel or perpendicular to the conductor depending on which current flow
convention is used
A
B. at right angles to the conductor
42
Q
- If a nail is brought to a bar magnet it is held by the magnet. If another nail
is now brought to touch the first nail it is held to the first nail.
Subsequent nails can be held in a long chain. This is a result of
A. induced magnetism
B. nail bonding
C. domain transfer
D. natural attraction of nail points to nail heads
A
A. induced magnetism
43
Q
- The end of the compass needle that points towards the northern region of the
earth is called
A. the north seeking pole
B. the magnetic north pole
C. the magnetic south pole
D. both a and b
A
D. both a and b
44
Q
- The magnetic north pole is located
A. at 90° north latitude
B. somewhere in northern Canada
C. at the north geographic pole
D. at Greenwich England
A
B. somewhere in northern Canada
45
Q
- A single line of force represents the unit of magnetic flux in a field. This
is called a(n)
A. oersted
B. gauss
C. weber
D. maxwell
A
D. maxwell
46
Q
- A magnet can lose its magnetism by
A. heating
B. hammering
C. both a and b
D. no known means
A
C. both a and b
47
Q
- Removal of magnetism from a part is termed
A. domain scattering
B. demagnetization
C. stress relieving
D. the Hall effect
A
B. demagnetization
48
Q
- A permanent magnet configured such that both north and south poles are
adjacent is usually termed a
A. longitudinal magnet
B. circular magnet
C. parallel magnet
D. horseshoe magnet
A
D. horseshoe magnet
49
Q
- The “image” of a magnetic field produced by placing a magnet under a paper and
sprinkling iron fillings on the top of the paper is called
A. magnetic projection
B. magnetic holography
C. a magnetograph
D. flux painting
A
C. a magnetograph
50
Q
- In direct current flow electric circuits, the unit of current is the
A. ampere
B. ohm
C. mho
D. volt
A
A. ampere
51
Q
- In alternating current electric circuits the unit of current flow is the
A. ampere
B. ohm
C. volt
D. deci Bell
A
A. ampere
52
Q
- Magnetic lines of force are
A. isolated mono-poles
B. elongated bi-poles
C. manifestations of the “string-theory”
D. imaginary concepts for mapping magnetic fields
A
D. imaginary concepts for mapping magnetic fields
53
Q
- Electric current which at regular intervals reverses its direction of flow is
called
A. AC
B. DC
C. alternating
D. both a and c
A
D. both a and c
54
Q
- Opposition to electric current flow in a D.C. circuit is termed
A. ohmage
B. resistance
C. reactance
D. reluctance
A
B. resistance
55
Q
- The unit of electrical resistance is the
A. ampere
B. coulomb
C. ohm
D. volt
A
C. ohm
56
Q
- The unit of potential difference in an electric circuit is the
A. ampere
B. ohm
C. volt
D. Coulomb
A
C. volt
57
Q
- A ferromagnetic material surrounded by a current carrying coil becomes
A. diamagnetic
B. magnetized
C. an electromagnet
D. both b and c
A
D. both b and c
58
Q
- The unit of inductance is the
A. farad
B. henry
C. Coulomb
D. abvolt
A
B. henry
59
Q
- The ability of a material to emit visible light while being irradiated by UV
light is called
A. fluorescence
B. phosphorescence
C. iridescence
D. Birefringence
A
A. fluorescence
60
Q
- The typical duration of a coil shot is
A. a fraction of a second
B. 1 second
C. 2 seconds
D. 5 seconds
A
A. a fraction of a second
61
Q
- The clamping contacts on a large stationary magnetic particle testing unit are
called
A. prods
B. heads
C. poles
D. shunts
A
B. heads
62
Q
- When a part is magnetized such that the flux lines run essentially parallel to
the long axis of the part it is called
A. parallel magnetization
B. circular magnetization
C. longitudinal magnetization
D. a long shot
A
C. longitudinal magnetization
63
Q
- In magnetic particle testing prods are
A. hand held electrodes
B. never used
C. used for longitudinal magnetization
D. substitutes for the central conductor
A
A. hand held electrodes
64
Q
- In electric circuit terminology, the usual symbol for voltage is
A. E
B. I
C. V
D. both a) and c) are used
A
D. both a) and c) are used
65
Q
- The common unit of electric power is
A. amperes
B. volts
C. watts
D. horsepower
A
C. watts
66
Q
- The relationship relating electric current flow, voltage and resistance in
electric circuits is
A. relativity
B. Ohm’s law
C. Snell’s law
D. Kirchoff’s law
A
B. Ohm’s law
67
Q
- In electric circuit terminology the usual symbol for current is
A. A
B. E
C. I
D. C
A
C. I
68
Q
- To determine the direction of magnetic field lines in a conductor (assuming -
to + current flow) you can use
A. the left hand rule
B. the right hand rule
C. a Galvanometer
D. a Wheatstone bridge
A
B. the right hand rule
69
Q
- For a single straight conductor, assuming modern theory current flow, the
fingers on the left hand point
A. in the direction of the magnetic field lines
B. against the magnetic field lines
C. in the directions of the electron flow
D. opposite to the electron flow
A
A. in the direction of the magnetic field lines
70
Q
- In the right hand rule as applied to a solenoid, the fingers point in the
direction of
A. north
B. south
C. current flow
D. force on the conductor
A
C. current flow
71
Q
- In the right hand rule, as it applies to a solenoid, the thumb point in the
direction of
A. north
B. south
C. current flow
D. force on the conductor
A
A. north
72
Q
- The relative amount of flux linkage between two coils (as in a transformer) is
called
A. mutual inductance
B. figure of merit
C. coupling coefficient
D. flux factor
A
C. coupling coefficient
73
Q
- In order to operate as a transformer, two coils must be linked by a(n)
A. iron core
B. air core
C. alternating magnetic field
D. copper wire
A
C. alternating magnetic field
74
Q
- The difference between a yoke and prods in magnetic particle testing is
A. a yoke produces a circular field and prods a longitudinal
B. a yoke produces a longitudinal field and prods a circular
C. a yoke produces a longitudinal field and prods a parallel
D. none, the both produce circular fields
A
B. a yoke produces a longitudinal field and prods a circular
75
Q
- As one increases the size of the MPI test system from small yokes and portable
units to large bench units the single most significant difference is
A. length of piece that can be tested
B. the ability to use liquid suspensions in the big units
C. the amount of magnetizing current available
D. type of magnetic field that can be generated
A
C. the amount of magnetizing current available
76
Q
- When single phase AC is halfwave rectified it is sometimes called half wave
direct current. The reference to direct current is because
A. Lenz’s law applies
B. current amplitude does not change
C. current flow direction does not change
D. all of the above
A
C. current flow direction does not change
77
Q
- A part that has been magnetized by ________ requires demagnetization.
A. mechanical means
B. magnetic particle testing
C. a magnetic chuck
D. none of the above
A
D. none of the above
78
Q
- Demagnetization of a part is usually required when the part is
A. used near magnetically affected instruments
B. part of a moving assembly
C. to be finish machined
D. all of the above
A
D. all of the above
79
Q
- The Curie point is
A. 320°C.
B. 1650°F.
C. varies with the position on the earth relative to the north magnetic pole
D. varies for each ferromagnetic alloy
A
D. varies for each ferromagnetic alloy
80
Q
- The number of reversals normally required to properly demagnetize a part using
electromagnetic means is
A. 1
B. 2-5
C. 10-30
D. 50-100
A
C. 10-30
81
Q
- Demagnetization can be accomplished using
A. A.C.
B. D.C.
C. a yoke
D. all of the above
A
D. all of the above
82
Q
- What shape is used for the particles used in magnetic particle testing?
A. acicular (elongated)
B. spherical and flake
C. irregular
D. all of the above
A
D. all of the above
83
Q
- Which is a type of particle available for magnetic particle testing?
A. wet visible particles
B. dry fluorescent particles
C. dry visible particles
D. all of the above
A
D. all of the above
84
Q
- What is the result if magnetic particles are made of a material of high
coercive force?
A. decreased mobility
B. high background
C. masking of defects
D. all of the above
A
D. all of the above
85
Q
- Large sized particles are not used in wet magnetic particle testing because
A. they drop from suspension too quickly
B. they form misleading indications called drainage lines
C. circulation pumps cannot move them off the tank bottom
D. both a and b
A
D. both a and b
86
Q
- The purpose of large particles in the dry powder mix is to
A. detect large defects
B. reduced background by “sweeping”
C. locate subsurface defects
D. both a and b
A
D. both a and b
87
Q
- The reason agglomerations of fine magnetic particles tend to move through the
liquid they are suspended in is
A. increased mass
B. increased field strength
C. both a and b
D. the fluid dynamic shape that is taken on
A
C. both a and b
88
Q
- Maximum particle mobility is had for dry magnetic particles with _______
shape.
A. spherical
B. elongated
C. flake
D. irregular
A
A. spherical
89
Q
- The reason for adding a portion of spherical shaped magnetic particles to a
batch of elongated shaped dry powder magnetic particles is to
A. increase density
B. increase mobility
C. increase sensitivity
D. increase contrast
A
B. increase mobility
90
Q
- The bulk magnetic indicator is not used for measuring
A. uniform magnetic induction fields in air
B. uniform magnetic field strength in air
C. the existence of a magnetic field external to a part
D. leakage fields from discontinuities
A
D. leakage fields from discontinuities
91
Q
- Daylight fluorescent dry magnetic particles
A. require a standard blacklight for viewing
B. require a special filter on the blacklight
C. fluoresce brightly in visible light
D. have no place in NDT
A
C. fluoresce brightly in visible light
92
Q
- In MPI testing using dry powder, mechanical blowers can be used for
A. particle application
B. removal of background particles
C. pre cleaning of gritty surfaces
D. both a and b
A
D. both a and b
93
Q
- Dry magnetic particle powders must be handled with care because
A. the ferrous powders and pigments are considered nuisance dusts
B. exposure to skin can cause acute melanoma
C. inhalation can result in silicosis
D. both b and c
A
A. the ferrous powders and pigments are considered nuisance dusts
94
Q
- For sensitive wet method magnetic particle testing, coloured particles are
typically 5 to 15 µm diameter. Unpigmented ferromagnetic oxides for the same
sensitivity would be
A. 0.5µm to 1.5µm
B. 50 µm to 150µm
C. 0.5mm to 1.5mm
D. useless
A
A. 0.5µm to 1.5µm
95
Q
- In general, likelihood of flaw detection by MPI is statistical and increases
with
A. flaw size
B. age of inspector
C. current used
D. amount of power (or ink) used
A
A. flaw size
96
Q
- Which is not a factor that will affect the level of magnetic flux leakage from
a flaw?
A. defect size
B. defect shape
C. part thickness
D. applied field strength
A
C. part thickness
97
Q
- What is the purpose of limiting the flux density generated in a piece being
MPI tested?
A. reduce the occurrence of false reporting of flaws
B. prevent arcing
C. ensure saturation is not achieved
D. provide more particle mobility
A
A. reduce the occurrence of false reporting of flaws
98
Q
- For precise delineation of the contour and extent of a magnetic particle
indication is required the best way to record it is
A. photography
B. tape transfer or lacquer
C. etching
D. hand sketches
A
B. tape transfer or lacquer
99
Q
- Flow lines found by MPI in a steel forging are
A. always rejectable
B. non-relevant indications
C. seen only with the aid of a microscope
D. evidence for magnetic domains
A
B. non-relevant indications
100
Q
- When photography of fluorescent indications is performed ____________ are used
to prevent overexposure of film.
A. F-stops
B. fish-eye lenses
C. special filters
D. black and white film
A
C. special filters
101
Q
- For photography of MPI indications the use of a tripod is recommended. Why?
A. the camera with all the attachments is too heavy
B. exposures are long and camera movement would ruin the shot
C. to facilitate a mount for the light meter
D. none of the above-tripods are never used
A
B. exposures are long and camera movement would ruin the shot
102
Q
- Photographs of fluorescent indications require which type of film?
A. instant black and white
B. regular black and white
C. regular colour
D. any of the above, generally no special film is needed
A
D. any of the above, generally no special film is needed
103
Q
- When a ferromagnetic material is placed in an inducting field H, and H is
increased until the incremental permeability is simply the free space
permeability this point is called the
A. magnetic saturation
B. inflection point
C. reversal point
D. Barkhausen limit
A
A. magnetic saturation
104
Q
- The small jumps in magnetism as a ferromagnetic material is exposed to an
increasing induction field are termed
A. incremental permeability
B. Delta M’s
C. magnetic scatter
D. Barkhausen jumps
A
D. Barkhausen jumps
105
Q
- In photography of NDT indications filters are often incorporated as part of
the lens optics, why?
A. to remove unwanted light
B. to balance colour of light used
C. both a and b
D. none of the above, filters are forbidden
A
C. both a and b
106
Q
- The slope of the virgin magnetization curve at the origin of a hysteresis plot
is called the
A. original magnetization
B. flux density
C. permitivity
D. initial permeability
A
D. initial permeability
107
Q
- A closed magnetic path through one or more materials is considered a magnetic
circuit. As such, it can be considered analogous to an electric circuit, the
magnetic equivalent to voltage is
A. reluctance
B. magnetostriction
C. magnetomotance
D. magneto-voltage
A
C. magnetomotance
108
Q
- The difference in colour between an MPI indication and the background colour
of the part tested is critical in evaluation of a part. The colour difference
is referred to as
A. contrast
B. lumens
C. luminosity
D. indication intensity
A
A. contrast
109
Q
- Dry magnetic particles should be applied so they have a minimum velocity when
they reach the test part. The reason being
A. to avoid a peening effect on the part
B. to ensure they can be caught by leakage fields
C. so pigments are not knocked off
D. all of the above
A
B. to ensure they can be caught by leakage fields
110
Q
- The choice of colour of dry magnetic particle to use depends on
A. colour of part being tested
B. ambient light at the test location
C. type of defect required to be found
D. both a and b
A
D. both a and b
111
Q
- What is the name of the technique whereby a part is magnetized first and the
particles applied after the magnetizing force is removed?
A. residual method
B. leakage field method
C. time lapse MPI
D. delay technique
A
A. residual method
112
Q
- What is the name of the MPI technique whereby the magnetic particles are
applied to a part only during the time the magnetizing force is applied?
A. the inertial technique
B. the continuous method
C. the synchronized method
D. the time-metered method
A
B. the continuous method
113
Q
- The purpose of contact pads placed on the electrodes used in MPI is
A. ornamental
B. to redirect flux patterns
C. top secret
D. to improve electrical contact
A
D. to improve electrical contact
114
Q
- The localized overheating of a part being magnetic particle tested, arising
from high resistance or sparking at the electrical contact point is
A. burning (or arcing)
B. coagulation
C. feedback
D. background noise
A
A. burning (or arcing)
115
Q
- The general appearance of the test surface on which indications are to be
viewed is termed
A. purple haze
B. backdrop
C. background
D. carrier
A
C. background
116
Q
- The buildup of magnetic particles due to excessive magnetization of the part
under test is called
A. furring
B. fall-out
C. magnetic hair
D. magnetic writing
A
A. furring
117
Q
- A “split-coil” attachment for MPI use is used for
A. varying the number of turns in a coil
B. varying the magnetizing current strength in the part
C. positioning over a part with no free ends for normal coil access
D. both a and b
A
C. positioning over a part with no free ends for normal coil access
118
Q
- A five turn coil on a bench unit is 30cm diameter. If 2000amps are passed
through it will result in
A. 10,000 ampere turns
B. 12,000 ampere turns
C. 60,000 ampere turns
D. unknown
A
A. 10,000 ampere turns
119
Q
119.The process whereby the magnitude and significance of an indication is
determined is termed
A. examination
B. interpretation
C. evaluation
D. rejection
A
C. evaluation
120
Q
- A “keeper” is used on a permanent magnet to complete the magnetic circuit. The
purpose of this is to
A. prevent loss of magnetism
B. provide an intensification of flux
C. provide longitudinal magnetization
D. provide circular magnetization
A
A. prevent loss of magnetism
121
Q
- Parallel magnetization is
A. not possible
B. not a recommended practice for MPI testing
C. the same as longitudinal magnetization
D. a substitute for overall magnetization
A
B. not a recommended practice for MPI testing
122
Q
- The non-relevant indication resulting when the surface of a magnetized part
comes in contact with another piece of ferromagnetic material is
A. bearding
B. furring
C. magnetic writing
D. break lines
A
C. magnetic writing
123
Q
- Which of the following materials has the highest relative permeability
A. iron
B. vacuum
C. air
D. gold
A
A. iron
124
Q
- The two basic decisions made before an MPI test is carried out are
A. minimum size of defect to find and type of current to use
B. minimum size of defect to find and type of particle to use
C. type of current and type of particle to use
D. which code to use and how fast to perform the test
A
C. type of current and type of particle to use
125
Q
- To detect a flaw in a low carbon steel shaft, if you suspect the flaw is about
6mm (1/4”) below the surface which method would you use?
A. A.C.
B. half wave rectified A.C.
C. an A.C. yoke
D. a pair of permanent magnets
A
B. half wave rectified A.C.
126
Q
- Which is the best material for detecting defects wholly below the surface
using MPI tests?
A. dry powder
B. wet fluorescent
C. wet visible
D. all are about equal for the same current
A
A. dry powder
127
Q
- Low carbon steels must have the continuous method of MPI testing used on them
due to
A. the skin effect
B. the Hall effect
C. low retentivity
D. carborization occurring from the residual method
A
C. low retentivity
128
Q
- The magnetizing current in the continuous wet method, when the bath is applied
by flooding from a nozzle, is usually applied
A. during the whole time it takes to wet the part
B. immediately after flooding is stopped
C. after the bath stops dripping from the part
D. both before and after bath application
A
B. immediately after flooding is stopped
129
Q
- The normal duration required for a magnetizing “shot” in the continuous wet
method is about
A. 1/4 to 1/2 second
B. 1/2 to 1 second
C. 1 to 2 seconds
D. 2 to 5 seconds
A
A. 1/4 to 1/2 second
130
Q
- Prods or clamps are used to produce which type of magnetization?
A. longitudinal
B. circular
C. parallel
D. swinging field
A
B. circular
131
Q
- When a central conductor is used inside a tube the type of magnetization
employed for the testing of that tube is
A. longitudinal
B. circular
C. parallel
D. swinging field
A
B. circular
132
Q
- Generally an electromagnetic yoke is considered to be used for producing
A. longitudinal magnetization
B. circular magnetization
C. field distortions
D. either a or b depending on if it is an A.C. or D.C. yoke
A
A. longitudinal magnetization
133
Q
- Field strengths of the magnetic field produced by a solenoid (or coil) can be
changed by
A. changing the number of coil loops
B. changing the current in the coil
C. both a and b
D. none of the above
A
C. both a and b
134
Q
- The guideline to use 40 amperes of magnetizing current per mm of part diameter
applies to
A. head shots
B. coil shots
C. central conductor shots
D. de-magnetization
A
A. head shots
135
Q
- If using the rule of thumb of 40 amps per mm of part diameter for a head shot,
what current is required to magnetize a 20mm diameter copper bar?
A. 400 amp
B. 800 amp
C. 1600 amp
D. none of the above
A
D. none of the above
136
Q
- For the same diameter, length and current used, the difference between using a
non-magnetic and a ferro-magnetic central conductor is
A. magnitude of magnetic field on the outside surface of the conductor
B. directions of defects detected
C. both a and b
D. no difference
A
A. magnitude of magnetic field on the outside surface of the conductor
137
Q
- When performing MPI using prods, the current used depends on
A. prod spacing
B. part thickness
C. prod diameter
D. both a and b
A
D. both a and b
138
Q
- If 24000 ampere turns are required for coil shot using a 5 turn bench coil,
what should your current setting be?
A. 2400 amps
B. 4800 amps
C. 12000 amps
D. 24000 amps
A
B. 4800 amps
139
Q
- In what way does surface roughness hinder the MPI test on a part?
A. hindrance of particle migration
B. reduction in contrast
C. distortion of the magnetic field
D. all of the above
A
D. all of the above
140
Q
- What do the following cleaning methods all have in common? Shot blasting, sand
blasting, wire brushing and scraping
A. none are used for precleaning a part for MPI
B. none require electricity
C. all are mechanical methods
D. all are environmentally friendly
A
C. all are mechanical methods
141
Q
- Which cleaning method is not likely to be used to remove oil films prior to an
MPI test?
A. vapour degreasing
B. wire brushing
C. steam cleaning
D. ultrasonic cleaning
A
B. wire brushing
142
Q
- The magnetic field produced by a yoke made of permanent magnets is _______
between the poles.
A. longitudinal
B. circular
C. both a and b
D. constantly varying
A
A. longitudinal
143
Q
- The swinging field MPI technique is used with
A. sequenced D.C.
B. combined D.C. and A.C. fields
C. combined A.C. fields
D. all of the above
A
D. all of the above
144
Q
- The advantage of the swinging field or multidirectional magnetization
technique is
A. cost of equipment
B. detection of small defects
C. time saving because it is single step test
D. both b and c
A
D. both b and c
145
Q
- When permeability of a material is quoted without an additional qualifying
term the permeability referred to is
A. initial permeability
B. incremental permeability
C. maximum permeability
D. osmotic permeability
A
C. maximum permeability
146
Q
- Current for circular magnetization of a part whose maximum permeability is 500
will be ___________ compared to a part with maximum permeability of 4000.
A. more
B. less
C. about the same
D. it depends if A.C. or D.C. is used
A
A. more
147
Q
- In MPI a handy rule of thumb relating current flow and suspected flaw
orientation is; current flow should be directed _______ major axis.
A. under suspected defects’
B. parallel to suspected defects’
C. perpendicular to suspected defects’
D. diagonally to suspected defects’
A
B. parallel to suspected defects’
148
Q
- The strength of a circular magnetic field is not diminished by ________ of a
part.
A. permeability
B. diameter
C. length
D. any of the above
A
C. length
149
Q
- A 2cm diameter pipe and a 2cm diameter bar of the same steel alloy are each
circularly magnetized by a 1000 amp D.C. head shot. The strongest magnetic
field will occur on the surface of the __________-.
A. bar
B. pipe
C. pipe if its wall is less than 0.5cm
D. none of the above, fields will be equal
A
D. none of the above, fields will be equal
150
Q
- When a hollow non-magnetic central conductor is used to induce a circular
magnetic field in a ferro-magnetic cylinder maximum field strength is at the
A. central conductor’s outside surface
B. central conductor’s inside surface
C. magnetic material’s inside surface
D. magnetic material’s outside surface
A
C. magnetic material’s inside surface
