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Mag Particle Practice > Mag Particle Practice > Flashcards

Mag Particle Practice Flashcards

1
Q

An electric current through a wire creates what

A

It creates a magnetic field around the wire

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2
Q

Since the magnetic lines of force within a bar magnet run the length of the bar, it is said to be

A

Longitudinally magnetized

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3
Q

Materials which are repelled magnetically are called

A

Diamagnetic

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4
Q

The general term used to refer to a break in the metallic continuity of the part being tested is

A

Discontinuity

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5
Q

The lines of force that form a path around a crack in a ring magnet that exit are called

A

Flux leakage

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6
Q

The pattern of iron powder sprinkled on a paper placed over a bar magnet is called

A

Magnetograph

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7
Q

A hysteresis loop is used to demonstrate a materials

A

Stress-strain relationship, magnetic properties

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8
Q

The relative magnetic permeability is dependent on

A

The specific properties of the material tested. The strength of the applied field

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9
Q

Multiple (more than two) poles existing along the length of a bar magnet are known as

A

Consequent

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10
Q

The property of a magnetic material to keep or retain a magnetic field after the magnetizing current is removed is called

A

Retentivity

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11
Q

Magnetic particle testing can be effectively used on which material

A

Ferromagnetic materials

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12
Q

Magnetic lines of force (Magnetic flux) will…..

A

Never cross each other

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13
Q

A continuous circular (ring shaped) test object without a leakage magnetic field will have _____ north and south poles

A

No detectable

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14
Q

The reverse magnetizing force required to remove remnant or residual magnetism and therefore demagnetize the part is called

A

Coercive force

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15
Q

These materials are slightly attracted by a magnetic field and the material does not retain the magnetic properties when the external field is removed is a

A

Paramagnetic material

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16
Q

A narrow hysteresis loop consists of what properties

A

High permeability, low retentivity, low coercive force, lower reluctance, lower residual magnetism

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17
Q

Rectified alternating current is sometimes referred to as _____ in magnetic particle testing

A

Half-or full-wave current

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18
Q

Alternating current is the preferred current for detecting ______ discontinuities

A

Surface

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19
Q

What rule best describes current flow (+ to -) when lines of magnetic force surround a conductor

A

Right hand rule

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20
Q

The areas on a magnetized part from which the magnetic field is leaving or entering into a part is called

A

Magnetic poles

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21
Q

A coil shot Is not as effective if the ratio of the long to short dimension is less than

A

2

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22
Q

When testing for fine shallow surface cracks, the preferred magnetic particle testing method should be

A

Wet AC

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23
Q

an electric current which flows steadily in one direction is a

A

Direct current

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24
Q

If 25 mm and 50 mm diameter bars were magnetized by passing the same current through them, the magnetic field would be

A

Stronger in the 25 mm diameter bar

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25
Q

Calibration of a yoke includes

A

Lifting a specified weight

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26
Q

Current values when using the headshot on a Mt bench unit are determined by

A

Determined by diameter of the part

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27
Q

Residual magnetism may be beneficial as an aid

A

In the interpretation and evaluation of indications

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28
Q

What kind of shot will produce a direct induction circular field in a test part

A

Head shot

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29
Q

A longitudinal field is generated in a test object by placing it in a coil, or by ____ cables (3 to 7 turns) around a test object

A

Wrapping

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30
Q

Penetration of the magnetic field, all other factors being equal, is greatest for

A

Half wave rectified single phase AC

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31
Q

Magnetic flux lines which are parallel to a discontinuity will produce a

A

No indication

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32
Q

A current passed through a magnetic central conductor will produce a magnetic field that is ____ a non-magnetic central conductor for the same size and current applied to the bar

A

Equal to

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33
Q

The small jumps in magnetism as a ferromagnetic material is exposed to an increased induction field are termed

A

Barkhausen effect (looks like stairs)

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34
Q

The unit used to denote flux density (symbol B) is the:

A

Gauss

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35
Q

The magnetizing force is applied and maintained while the magnetic particles are dusted or flowed onto the surface of the component is considered a

A

Continuous method

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36
Q

A yoke creates a _____ magnetic field

A

Longitudinal

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37
Q

The left hand rule for determining magnetic field direction applies to

A

Modern current theory (- to +)

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38
Q

The fact that only some magnetic domains resume a random orientation when the magnetizing field is removed accounts for what

A

Retentivity

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39
Q

The build-up of magnetic particle due to excessive magnization of the part under test us called

A

Furring

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40
Q

What direction of magnetic field is produced when passing a current directly through a test part

A

Circular

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41
Q

The magnetic field created by a head shot or central conductor is _____ for the entire length of the test object

A

Uniform

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42
Q

What type of equipment is similar to a temporary horseshoe magnet

A

Yoke

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43
Q

Magnetic particles should have which of the following properties?

A

Low retentivity/ high permeability

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44
Q

A magnetic flux leakage field can be caused by magnetic lines of force leaving or entering a test object where their path is _____ by a discontinuity

A

Distorted

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45
Q

A central conductor will produce a circular field with_____ danger of burning or ruining the test object

A

Minimal

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46
Q

The purpose of lead contact covers on prods for mpi testing is to

A

Reduce arc burns

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47
Q

The settling test should be performed once for new mixtures of solution and

A

Before each use

48
Q

Ultraviolet radiation intensity used for testing must be a minimum of _____

A

1000 uW/cm squared

49
Q

Too much current will produce ______ indication or______ background

A

Non relevant or excessive

50
Q

The end of the magnet at which the line of force are thought of entering the magnet is the

A

South pole

51
Q

Magnetic line of force can be described as

A

Having the same strength, seek the path of less resistance, decrease in density with increasing distance from poles (all of the above)

52
Q

A material is considered demagnetized when

A

It’s residual magnetism field measures less then 3 gauss

53
Q

Defects found between prods are aligned _____ the line between the prods:

A

Parallel to

54
Q

The width of a magnetic particle indication is what size in relation to the actual flaw

A

Is always wider than the actual flaw opening

55
Q

The property of a material that describes the ease with which a magnetic flux is established In a component is called

A

Permeability

56
Q

The particle shape of dry magnetic particles that is best suited to detection of weak leakage field from subsurface defects is

A

Elongated

57
Q

Electric current periodically reversing in polarity or direction is

A

Alternating current

58
Q

In a ferromagnetic material, a region where all the “atomic moments” are aligned parallel to each other is called a

A

Domain

59
Q

In order to be detectable by magnetic particle testing, a flaw must

A

Produce a leakage field at the surface

60
Q

The point at which the magnetism in a material cannot be increased aven though the magnetizing force continues to increase

A

Saturation point

61
Q

The flux density of the magnetism induced by a coil can be controlled by varying

A

The coil size, the current in the coil, the number of turns in a coil (all of the above)

62
Q

The negative magnetizing force required to reduce the residual flux density in a part to zero after saturation is called

A

Coercive force

63
Q

Where is the most logical place, on a casting, to look for discontinuities

A

At junction between light and heavy sections

64
Q

The strength of a circular magnetic field is not diminished by ____ of a part

A

Length

65
Q

When the central conductor mpi method is used to inspect a ring shaped object, or short cylinder

A

Both inside and outside surface and subsurface flaws can be found if the wall thickness is not too great

66
Q

When welds are required to have only partial penetration used of HWDC yokes often give rise to non relevant indications. This problem can be eliminated by

A

Using an AC yoke

67
Q

If a discontinuity is shallow and broad like a scratch, the flux lines my stream-line below the discontinuity. This will result in

A

A lack of indication

68
Q

The magnetic field is strongest when

A

The magnetizing current is flowing

69
Q

The proper number of amere-turns for a given test specimen being examined by longitudinal magnetism is determined by

A

It’s length and diameter

70
Q

A circular field may be induced into a specimen by

A

Passing current directly through the part

71
Q

Aircraft, automotive, and railroad components that have been in-service for some time but not near an artificially produced magnetic field are often found to be strongly magnetized. This is a result of

A

The earth’s magnetic field

72
Q

A magnetic particle cluster resulting from a true leakage field but not originating from a metal flaw is a

A

Non-relevant indication

73
Q

An eye that has adapted to bright daylight is said to be exhibiting

A

Photopic

74
Q

Which magnetic particle application technique is the most sensitive

A

Continuous

75
Q

Fluorescent magnetic particle indications should be inspected under

A

An ultraviolet light

76
Q

The direction of magnetic lines of force are _____ degrees from the direction of current flow

A

90°

77
Q

Demagnetization may be accomplished by ____

A

Heating a material above its curie point

78
Q

What are 4 methods used with direct induction

A

Head shot, prods, clamps, magnetic leaches

79
Q

What are four methods used with indirect induction

A

Central conductor bar, permanent magnets, ac yoke, coil/solenoid

80
Q

What is the approximate permeability value for the following diamagnetic, paramagnetic, ferromagnetic

A

Diamagnetic is less than 1
Paramagnetic is slightly greater than 1
Ferromagnetic is much greater than 1

81
Q

Its usually preferable to disassemble parts before magnetic particle inspection. True or false

A

True

82
Q

Over inspection is not a serious problem in magnetic particle inspection. True/ false

A

False

83
Q

Defects in brass parts can be detected with wet fluorescent magnetic particle. True or false

A

False

84
Q

What is the most effective way of demagnetization

A

Heat above curie temp

85
Q

What is the common unit used to measure wavelength

A

Nm

86
Q

List two reasons why the filter should always be in place on a mercury vapor-arc lamp

A

Removes the short wave ultraviolet light
Removes most of the white light that the lamp produces

87
Q

All parts with indications should be scrapped. True or false

A

False

88
Q

Black powder gives a better visual contrast on dark heat treated scaly parts. True or false

A

False

89
Q

A circular field is easily measured with a field meter. True or false

A

False

90
Q

When magnetizing a Weld in two directions if the amperage used in the first direction is 750 A and the amperage in the second direction is 400 A. Then the section or part should be demagnetized between operations. True or false

A

True

91
Q

Heating to 800°C will cause ferromagnetic material to become magnetic. True or false

A

False

92
Q

What is the minimum eye adaptation time required to perform fluorescent magnetic particle examination

A

5 min in dark room before start of inspection

93
Q

A pear shaped centrifuge (wet bench) used for fluorescent particle has what size of stem and division

A

1 ml stem and 0.05 division

94
Q

Prods should not be used on what type of components or surface

A

Aerospace components or machined surface

95
Q

When performing a coil shot with a low fill factor the L/D ratio should be

A

Between 3-15

96
Q

List the recommended verification intervals for UV-A, water break test, ammeter check, gaussmeter

A

UV-A-daily,
water break test-daily,
Ammeter check-6 month, Gaussmeter-6 month

97
Q

Permanent recording of magnetic particle indication may be done by

A

Written description, transparent tape, strippable film, photography

98
Q

When using fluorescent particle, personnel shall not wear what type of eye glasses

A

Photochromic or that permanently darkened lenses

99
Q

After demagnetization a calibration field indicator shall not detect magnetic flux fields with an absolute value above

A

Above 3 G (3x10(to the power of-4) T)

100
Q

The unit usually used to denote flux density is

A

Tesla

101
Q

Magnetic lines of force are most dense at

A

The poles of the magnet

102
Q

The proper number of ampere-turns for a given test specimen being examined by longitudinal magnetism is determined by

A

It’s length and diameter

103
Q

A circular field may be induced into a specimen by

A

Passing current directly through the part

104
Q

An electric yoke produces what kind of field

A

A longitudinal field

105
Q

Proper term for calculating magnetic force is called

A

Amper turns

106
Q

Magnetic lines of force form a_____

A

Closed loop

107
Q

The amount of amperage used for magnetic particle inspection using the prod technique is determined from the

A

Distance between the prods and thickness of the material

108
Q

A metal that is difficult to magnetize is said to have

A

Low permeability

109
Q

Subsurface discontinuity indications usually appear

A

Wide and fuzzy

110
Q

What technique of applying particle provides greater sensitivity in locating subsurface WELD discontinuity

A

Continuous

111
Q

When a ferromagnetic object is placed inside a coil carrying an electric current the magnetic lines of flux concentrate themselves in what direction

A

A longitudinal direction

112
Q

What are three causes of nonrelevant indication

A

Sharp corners, heat affected zones, drill hole near surface

113
Q

Using the residual testing technique, a number of parts are magnetized and laid on a rack prior to application of magnetic particle. Why is it Important that they do not rub or touch each other

A

It may cause magnetic writing

114
Q

The strongest magnetic field in a coil is at the_____

A

Inside edge

115
Q

Which of the following is most often used for dry magnetic particle inspection

A

Half wave direct current

116
Q

In circular magnetization, the magnetic force is expressed in amperes. What term is used to express magnetizing force in longitudinal magnetization?

A

Amper-turns

Mag Particle Practice (1 decks)

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