CGSB Study Q’s Flashcards
1
Q
Which of the following materials can be examined by the MPI method?
A) medium alloy steels
B) carbon steels
C) aluminum
D) magnesium
E) brass-copper
F) bronze
G) lead
H) ferro magnetic metals
A
Medium alloy steels, carbon steels and ferro magnetic metals
2
Q
Any mass of iron, steel, or material capable of attracting other like masses is known as what?
A
Magnet
3
Q
When the flux lines or lines of force traverse the part in a direction essentially parallel to the long axis of the test piece, the lines of force tend to return through the air from one pole to the other forming a closed magnetic field. This is known as what type of magnetism?
A) circular
B) longitudinal
C) transverse
D) continuous
A
B) longitudinal
4
Q
In what manner has the part been magnetized when the magnetic flux always has a completely ferromagnetic return?
A) circular
B) longitudinal
C) transverse
D) continuous
A
A) circular
5
Q
When longitudinally magnetizing a part in a coil, how is the effective amperage determined?
A) amperage applied multiplied by number of turns in coil
B) number of turns in coil multiplied by width of part
C) amperage indicated by ammeter
D) I = E/R
A
A) amperage applied multiplied by number of turns in coil
6
Q
Through what medium are discontinuities demonstrated in magnetic particle inspection?
A) finely divided ferromagnetic particles of high permeability, low coercive force and very high retentivity
B) finely divided ferromagnetic particles of high permeability and low retentivity
C) red oil like substance with good capillary action
D) metal shavings and particles
A
B) finely divided ferromagnetic particles of high permeability and low retentivity
7
Q
When the finely divided ferromagnetic particles are in oil suspension, the test method is called;
A) oil and whiting technique
B) oil suspension technique
C) wet method
D) spray or dip method
A
C) wet method
8
Q
A sharp variation in the permeability of material being inspected causing a magnetic particle indication is called a:
A) defect
B) discontinuity
C) nonrelevant indication
D) false indication
A
B) discontinuity
9
Q
What is the most effective means of magnetization for the detection of extremely deep-lying defects? (2)
A) dry residual method using DC with surge
B) wet continuous method using half wave with rectified current
C) dry continuous method using DC with surge
D) dry continuous method using half wave rectified current with prods
A
C) dry continuous method using DC with surge AND, D) dry continuous method using half wave rectified current with prods
10
Q
How are the particles held to the part in false indications?
A) magnetic pole
B) discontinuity
C) gravity or mechanically
D) leakage field
A
C) gravity or mechanically
11
Q
Assuming that a part is to be magnetized longitudinally after a circular shot, is it necessary to demagnetized between shots? Why?
A
No because the second shot will cancel out the previous field
12
Q
The Tesla is the unit of measurement of the magnetic field strength. What is the term which is used in this regard?
A) current
B) flux density
C) lines of force
D) residual field
A
B) flux density
13
Q
What type of current is better for locating subsurface defects?
A) AC
B) DC
A
B) DC
14
Q
Define magnetic poles:
A
The ability of a magnet to attract or repel is not uniform over its surface, but concentrated at local areas called poles.
Each magnetic has at least two opposite poles: one which is attracted to the Earth’s North Pole and called the North Pole of the magnet, while the other is attracted to the Earth’s South Pole which is called the South Pole of the magnet.
15
Q
Define permanent magnets:
A
Occur in nature as the mineral “magnetite” or made by artificially magnetizing hardened steels or alloys such as alnico.
They will retain their magnetic field after the magnetizing influence has been removed.
16
Q
Is the compass test for residual magnetism applicable to parts magnetized circularly?
A
No
17
Q
What are three causes of nonrelevant indications?
A) lack of fusion
B) change in section
C) drilled holes near test surface
D) grinding cracks
E) very high amperage
F) blow holes
A
Change in section, drilled holes near test surface and very high amperage
18
Q
Using the residual test method, a number of parts are magnetized and laid on a rack prior to application of magnetic particles. Why is it important that they do not rub together?
A
False indications will be formed at localized poles at points of contact
19
Q
Define remnant magnetism:
A
The residual magnetism remaining in a magnetic circuit after the magnetizing influence has been removed
20
Q
Define temporary magnets:
A
Retain only a very small field after the magnetizing influence has been removed.
21
Q
The magnetizing field surrounding a bar magnet is most dense:
A) near the middle of the magnet
B) at ends of the magnet
C) 300 mm from the magnet
A
B) at ends of the magnet
22
Q
To locate defects, part should be magnetized so that the long axis of possible defects:
A) is at right angle to lines of force
B) is parallel to lines of force
A
A) is at right angle to lines of force
23
Q
Residual magnetic particle inspection may be used when: (2)
A) parts are irregular in shape
B) parts are highly retentive
C) parts are highly stressed
D) to help evaluate continuous method indications
A
B) parts are highly retentive AND D) to help evaluate continuous method indications
24
Q
When electric current is passed through a coil, the direction of the lines of flux induces in a rod positioned within the coil is:
A) circular
B) unknown
C) longitudinal
D) vector
A
C) longitudinal
25
Magnetic particle inspection is not a reliable method of detecting: (2)
A) laps
B) laminations
C) deep seated cavities
D) seams
B) laminations and C) deep seated cavities
26
Define solenoid:
An electric conductor formed into coils
27
Name four common ferromagnetic materials which can be inspected by the magnetic particle method.
Iron, nickel, cobalt and some steels
28
Which two methods which will produce circular magnetism?
A) passing current through the test part
B) placing test part in a solenoid
C) pass current though a central conductor
À) passing current through the test part AND C) pass current through a central conductor
29
What type of current is usually used with a demagnetizer?
Alternating Current
30
Is it possible to magnetic with DC?
Yes
31
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
D) imaginary concepts for mapping magnetic fields
32
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
C) domain
33
In order to be detectable by magnetic particle testing, a flaw must:
A) be surface breaking
B) be no deeper than 1 mm below the surface
C) produce a leakage field at the test surface
D) all of the above
C) produce a leakage field at the test surface
34
A good in an otherwise homogenous magnetized material presents itself as a point magnetic dipole. This is the basis for:
A) magnetic particle flaw detection
B) multifrequency eddy current
C) para-magnetism
D) de-magnetization
A) magnetic particle flaw detection
35
The opposition to the formation of a magnetic flux in a magnetic circuit is referred to as:
A) reactance
B) reluctance
C) resistance
D) antimagnetics
C) resistance
36
The value of H applied to bring the residual value of B to zero is called:
A) saturation field
B) demagnetization value
C) coercive force
D) phase reversal factor
C) coercive force
37
A magnetic particle build up from a discontinuity is strongest when the discontinuity is oriented:
A) 180• to the magnetic field
B) 45• to the magnetic field
C) 90• to the magnetic field
D) 90• to the current flow
C) 90• to the magnetic field
38
Grain boundaries are areas of a metal micro structure:
A) where high melting point constituents are concentrated
B) made up of rows of atoms arrayed in straight lines
C) that are not attacked by etchants and generally stand in relief during metallographic examination
D) where low melting impurities tend to concentrate
D) where low melting impurities tend to concentrate
39
Steels that contain more than 0.30% carbon, if welded, are prone to which type of discontinuity?
A) HAZ cracking
B) porosity
C) incomplete fusion
D) slag formation
A) HAZ cracking
40
What are the three main types of corrosion?
A) General corrosion, pitting and intergranular corrosion
B) General corrosion, pitting and transgranular corrosion
C) General corrosion, intergranular corrosion and transgranular corrosion
D) transgranular corrosion, intergranular corrosion and pitting
A) General corrosion, pitting and intergranular corrosion
41
What is the cause of the cracks in the HAZ?
A) a thermal cycle that increases hardness and reduces brittleness
B) a thermal cycle that reduces hardness and increases brittleness
C) a thermal cycle that reduces hardness and brittleness
D) a thermal cycle that increases hardness and brittleness
D) a thermal cycle that INCREASES hardness AND brittleness
42
Elongated configurations of foreign substances aligned in the direction of working wrought metals are called:
A) slag
B) inclusions
C) stringers
D) worms
C) stringers
43
A defect which bears no relation to the direction of metal grains is:
A) intergranular corrosion
B) grinding crack
C) quenching crack
D) lamellar tearing
B) grinding crack
44
The strength of a circular magnetic field is not affected by the _________ of a part:
A) permeability
B) diameter
C) length
D) any of the above
C) length
45
Given a steel bar 1 foot long and 3 inches diameter, what current should you use for the coil shot with a 3 turn coil (part placed at bottom of coil)?
A) 100 amps
B) 2000 amps
C) 4000 amps
D) 6000 amps
B) 2000 amps
46
When welds are required to have only partial penetration use of HWDC yokes often give rise to nonrelevant indications. This problem can be eliminated by:
A) using an AC yoke
B) increasing leg spacing
C) reducing magnetizing current
D) using a pie gauge
A) using an AC yoke
47
The best way to demagnetize a long tube would be:
A) reversing DC with a central conductor
B) pulsating AC with a central conductor
C) a portable yoke
D) passing the tube through an AC coil
A) reversing DC with a central conductor
48
Unless subsequently heat treated, all parts must be demagnetized after inspection.
True or False
False
49
When mixing magnetic particle paste with oil, it is permissible to mix directly in the equipment tank.
True or False
False
50
Which of the following is most often used for dry magnetic particle inspection?
A) cycle direct current
B) half wave rectified alternating current
C) high voltage, low amperage current
D) direct current from electrolytic cells
B) half wave rectified alternating current
51
Why should parts be clean prior to inspection? (2)
A) so the operator can stay clean
B) to assure correct indications
C) to keep suspension clean
D) to help make final cleaning easier
B) to assure correct indications AND C) to keep suspension clean
52
Why are parts demagnetized? (3)
A) so that parts can be handled easier
B) to assure removal of residual magnetism
C) to assist in cleaning of parts
D) if not done, subsequent machining operations may be more difficult to accomplish satisfactory
B) to assure removal of residual magnetism, C) to assist in cleaning of parts and D) if not done, subsequent machining operations may be more difficult to accomplish satisfactory
53
Why is black light used with fluorescent magnetic particle inspection? (2)
A) to protect the operator’s eyes
B) indications are more easily seen
C) to bring out the dye
D) to bring out the magnetism
B) indications are more easily seen AND C) to bring out the dye
54
Why should parts be cleaned after demagnetization? (2)
A) to assure that magnetic particles are removed
B) to prevent corrosive action
C) to save the solids of the suspension
D) to prevent cracking during heat treatment
A) to assure that magnetic particles are removed AND B) to prevent corrosive action
55
If many like parts are coming through inspection and are found rejectable, the thing to do is:
A) tell operator
B) inform supervisor
C) determine cause
D) scrap like parts and save test time
B) inform supervisor
56
Which of the following apply to magnetizing by use of a central conductor?
A) effective way to develop magnetic field on inside surface
B) enable operator to magnetize several washer shaped parts at same time
C) reduces danger of burning parts due to poor contact
D) can be used for residual and/or continuous method
E) all of the above
E) all of the above
57
What is the magnetizing force expressed in for circular magnetism?
Amperes
58
What is the magnetizing force expressed in for longitudinal magnetism?
Ampere turns
59
When demagnetizing with the prod method the initial magnetizing force used to demagnetize must be:
A) higher than that used to magnetize the part
B) lower than that used to magnetize the part
C) the same as that used to magnetize the part
D) doesn’t matter
A) higher than that used to magnetize the part
60
If a bar magnet were bent into a circular shape and the ends faced together (without heating), it would:
A) lose its polarity
B) increase its magnetization
C) still have a north and South Pole
D)develop a third pole
C) still have a North and South Pole
61
A crack in a circular (completely closed) magnet will cause:
A) the magnetic field to die out
B) polarity
C) magnetization
D) a current to flow
B) polarity
62
If a bar magnet is bent into a circular shape and the ends fused together in a perfect weld, it would:
A) lose its magnetism
B) lose its polarity
C) increase its magnetization
D) increase its polarity
B) lose its polarity
63
Circular magnetization is useful in the detection of:
A) circular cracks
B) longitudinal cracks
C) cracks in circular parts
D) “pipes”
B) longitudinal
64
In a magnetic particle test, assuming that all are in the same relative position in a small part, which of the following would be hardest to detect?
A) a surface crack
B) a sub-surface crack
C) a scratch
D) a seam
C) a scratch
65
In circular magnetization, the current used in testing is generally determined by:
A) the type of steel of the part
B) the diameter of the part
C) the shape of the part
D) the length of the part
B) the diameter of the part
66
The liquid inspection medium is correctly called:
A) solution
B) suspension
C) bath
D) rinse
B) suspension
67
Wet magnetic particle suspension should be made uniform because if not, then:
A) buildups may occur where there are no cracks
B) different mixtures would give different results
C) the magnetic flux would not be uniform
D) greater mobility would be required
B) different mixtures would give different results
68
The success of deep weld defect detection depends on: (2)
A) the surface must be free of scale, slag and must be dry
B) the magnetic particles must be free to move on weld surface
C) the surface must have a fine coat of oil
D) there must be paint or paste between the ripples
A) surface must be free of scale, slag and must be dry AND B) the magnetic particles must be free to move on weld surface
69
Powder which lies loosely in the depression at the side of the weld is:
A) a nonrelevant indication
B) a false indication
C) lack fusion
D) a magnetic anomaly
B) a false indication
70
How may one distinguish magnetic writing from a true discontinuity?
Magnetic writing will not reappear if demagnetized and retested
71
The nearest attainable approach to a leakage free magnetization is obtained by placing a part between the head stocks on a magnetic particle test machine.
True or False
True
72
A circular field is easily measured with a field meter.
True or False
False
73
The length of the part being magnetized by passing an electric current from one end to the other does not affect the strength of the magnetic field produced.
True or False
True
74
If absolute complete demagnetization is required after test, it may be advantageous to test with which of the following currents?
A) DC
B) AC
C) half wave
D) surge
B) AC
75
Which of the following will better define surface cracks?
A) half wave rectified AC
B) DC
C) AC
D) surge current
C) AC
76
**How much black or red magnetic paste is used per litre of oil for the wet method?
A) 7.5 g
B) 15 g
C) 11 g
D) 3.5 g
C) 11 g
77
When using the ASTM pear shaped 100 mL tube for checking the fluorescent magnetic particle content of suspension bath, the recommended particle content is the value shown or from within the range of values:
A) 11 g
B) 0.1 to 1.3 mL
C) 1.5 mL
D) 1.2 to 2.4 mL
B) 0.1 to 1.3 mL
78
How often should the bath strength (suspension concentration) be checked?
Daily, prior to use
79
When using the ASTM pear shaped 100 mL tube for checking the black or red magnetic particle content of the suspension bath, the recommended content is within the range of values:
A) 34 to 85 g
B) 1.2 to 2.4 mL
C) 0.1 to 0.7 mL
D) 28 to 85 g
B) 1.2 to 2.4 mL
80
Before mixing a new bath for the wet method, what is the first thing that should be done?
Thoroughly clean all equipment
81
How often should a wet method bath be changed?
Weekly if in production OR monthly if inspection is low and it remains uncontaminated
82
What are the recommended current requirements when using circular magnetization for tubular parts in a central conductor?
500 AMPS for every 12.5 mm of diameter (based on the outside diameter of test part)
83
Which of the following make the best after rinse for wet magnetic particle method using an oil suspension?
A) kerosene
B) gasoline
C) turpentine
À) kérosène
84
The approximate amperage used to circularly magnetize a 12 mm diameter bolt is:
A) 200
B) 500
C) 1000
D) 2500
B) 500
85
When testing to the requirements of Mil-l-6868B, how are parts identified to indicate magnetic particle inspection acceptance?
A) painting with aluminum paint
B) stamping, etching, tagging with ‘M’ or dying
C) various colour codes
D) stamping, etching, tagging with ‘OK’ or dying
B) stamping, etching, tagging with ‘M’ or dying
86
As minimum inspection, when magnetic particle inspection is a customer acceptance requirement, when should the test be conducted? (2)
A) prior to machining operations
B) after all machining operations
C) after heat treatment of metals
B) after all machining operations AND C) after heat treatment of metals
87
What amperage may be used with the prods spaced 150 mm?
A) 250 to 400 A
B) 600 to 800 A
C) 600 to 1000 A
D) 750 to 1000 A
B) 600 to 800 A
88
For a circular magnetization of hollow cylindrically shaped parts by central conductor, or of solid cylindrically shaped parts by passing current directly through the part, the magnetizing current should :
A) 1000 to 2000 A per 25 mm of outside diameter
B) 800 to 1000 A per 25 mm of max cross section
C) 300 to 500 A per 25 mm of diameter
B) 800 to 1000 A per 25 mm of max cross section
89
When searching for subsurface weld defects, especially on rough surfaces, the test surface preferable should be in the horizontal position.
True or False
True
90
If given a choice of half wave rectified AC or a magnetic yoke for inspection of welds over 20 mm thick, which would you use?
Half wave rectified AC
91
The same test results can be expected from using prod spacing of 150 mm at 650 A or using 300 mm at 1300 A.
True or False
False
92
For which of the listed thicknesses is a prod spacing of 150 to 200 mm satisfactory? (The length is 1800 mm in all instances)
A) 12 mm thick
B) 25 mm thick
C) 60 mm thick
D) all of the above
D) all of the above
93
Flow lines in forging are cause for rejection.
True or False
False
94
If a part is placed within several coils formed by the leads from a portable magnetic particle testing machine and the prods are joined, then the current turned in, how can one determine that the part can be tested by the magnetic particle method?
A) the part should get hot
B) the part will turn red
C) no reaction
D) a distinct pull of the part towards the coil will be felt
E) the part will feel magnetic
D) a distinct pull of the part towards the coil will be felt
95
Parts with a fine machined surface should be tested with prods.
True or False
False
96
If a test part is struck or burned by magnetic particle test contact prods or heads, the following should be done:
A) retest
B) grind area, retest area, inform supervisor
C) nothing
D) scrap, and inform supervisor
B) grind area, retest area and inform supervisor
97
If cables or leads from the prod type magnetic particle machine are wrapped around a part, the part will contain what type of field?
A) circular
B) electromagnetic
C) longitudinal
D) radiation
C) longitudinal
98
When a magnetic field is induced in a part with prods spaces 150 mm apart, the field is:
A) solenoid
B) circular
C) longitudinal
D) distorted circular
D) distorted circular
99
What type of steel is most favorable for deep defect detection and why?
A) low carbon steel, high permeability
B) low carbon steel, low permeability
C) high carbon steel, high coercive force
D) high carbon steel, high permeability
À) low carbon steel, high permeability
100
Discontinuities in plate, sheet or strip caused by pipe, inclusions or blowholes in the original ingot which after rolling are usually flat and parallel to the outside surface, are called what?
A) seams
B) laminations
C) cracks
D) laps
B) laminations
101
What would be the cause of a weld being magnetic particle tested shows a broad indication just beyond the opposite edge of the fusion zone?
Boundaries at heat treated sections
102
What would be the cause of a pad on a cast valve body that has an indication completely around it where the pad merged with the sides walls of the body?
Abrupt changes in section
103
Can austenitic steels be magnetic particle tested?
No
104
Comparing parts that have been circularly magnetized and those which have been longitudinally magnetized, which retains the most objectionable residual field if not demagnetized?
A) longitudinal
B) circular
À) longitudinal
105
Which of the two is more easily demagnetized from the standpoint of orientation of residual field only?
A) longitudinal
B) circular
À) longitudinal
106
An indication in MPI, that is held mechanically and not magnetically is known as:
A) forging burst
B) a non-relevant indication
C) a false indication
D) magnetic writing
C) a false indication
107
Why are large soft contact areas such as lead or copper braid favoured for contact surfaces on head stocks?
A) to increase contact area and reduce current density
B) low melting point
C) helps to heat metal, facilitating magnetic induction
À) to increase contact area and reduce current density
108
25 and /pr 50 Hz current can be used for demagnetizations.
True or False
True
109
What does the field gauge indicate?
A) amount residual magnetism in part
B) polarity and leakage field relative intensity
C) remnant magnetism
B) polarity and leakage field relative instensity
110
Produced by rectifying single phase alternating current is:
A) direct current
B) half wave current
C) full wave current
B) half wave current
111
Produced by rectifying three phase alternating current is:
A) half wave current
B) full wave current
C) cyclic current
B) full wave current
112
Seams in rolled bars are best detected in magnetic particle inspection with:
A) longitudinal magnetization
B) circular magnetization
C) prod magnetization
D) swinging field magnetization
B) circular magnetization
113
Fine surface defects such as fatigue cracks on smoothly machined parts which have been in service are best detected with MPI by use of:
A) dry mag particles with DC mag
B) wet mag particles with AC mag
C) dry mag particles with HWRC
D) wet mag particles with HWRC
B) wet mag particles with AC mag
114
To be able to most effectively locate or detect in a large casting, disregarding economic aspects:
A) pass current between prod contacts taking 150 to 200 mm at a time
B) pass current through ends of casting
C) the permeability should be low so that strong fields are not formed to mask detection
D) pass current so that field is parallel to discontinuity
A) pass current between prod contacts taking 150 to 200 mm at a time when
115
Wet fluorescent MPI is sometimes used in preference to coloured MP for which of the following reasons?
A) to increase speed and accuracy of scanning
B) to take advantage of the effects of fluorescent lights now becoming standard lighting in many plants
C) when the parts are large and bulky
D) if the parts are for the railroad and must meet AAR standards
A) to increase speed and accuracy of scanning
116
It is easier to remove surface defects from the raw castings that from machined parts because:
A) castings have rough surfaces
B) machined parts of higher alloy content
C) dimensional allowances are greater for the raw casting
D) machined parts are more likely to be magnetic
C) dimensional allowances are greater for the raw casting
117
Trepanning is extensively used to obtain samples of ___________ in heavy plate and weldments:
A) remnant field
B) cross section
C) tensile samples
D) bend tests
B) cross section
118
The magnetizing method that can be used most universally is that of the:
A) circular field
B) longitudinal field
C) bipolar field
D) a yoke field
À) circular field
119
One of the reasons low voltage rectifiers are used instead of line voltage DC is:
A) they are safer
B) they are too bulky
C) they produce more power
D) they produce AC
À) they are safer
120
Welding generators are not very satisfactory for the use in circular magnetization because why? (2)
A) they are too bulky
B) arcing is likely to occur at contact points
C) DC is produced
D) the current fluctuates too much
B) arcing is likely to occur at contact points AND D) the current fluctuates too much
121
For a given current through a conductor, doubling the diameter of the conductor will ___________ the field strength at the surface.
A) increase
B) decrease
C) double
D) quadruple
B) decrease
122
External fields that are too strong to permit good examination of a part are usually created by:
A) circular magnetization
B) residual magnetization
C) yoke magnetization
D) biopolar magnetization
C) yoke magnetization
123
Multiple (more than two) poles existing along the length of a bar magnet are known as ________ poles.
A) biopolar
B) internal
C) consequent
D) non relevant
C) consequent
124
Normally a satisfactory weld inspection can be performed after the following surface conditioning:
A) grind bead flush with plate
B) filling the ripple of a weld bead with paste or paint
C) wire brushing, sand or grit blasting
D) acid etch
C) wire brushing, sand or grit blasting
125
A thin cadmium plating will not seriously reduce the sensitivity of MPI.
True or False
True
126
When two magnetic fields of different directional properties are simultaneously imposed on a part( the result is a field whose strength and direction is the _____________ of the two fields:
A) stronger
B) vector sum
C) asymmetrical circular
D) weaker
B) vector sum
127
When testing with DC, an indication appears, to help determine whether the defect is near surface or sub-surface, the next step would logically be: (2)
A) observe powder build up, wipe off, observe surface
B) retest with AC
C) demag and apply powder
D) retest with surge current
À) observe powder build up, wipe off, observe surface AND B) retest with AC
128
A heavy flange section welded to a thin plate will often show a linear indication on the weld surface directly above the jointure of the two parts. This may be due to which? (3)
A) constriction of the field due to transition ‘thick to thin’ section
B) open root (no pen)
C) difference in permeability of plate and flange material
D) insufficient amperage
E) all of the above
À) constriction of the field due to transition ‘thick to thin’ section, B) open root (no pen) and C) difference in permeability of plate flange material
129
Nonrelevant indications due to residual local poles interfere with MPI. For a successful exam, one should:
A) use more amperage
B) demag then remag in the desired direction
C) use lower amperage
D) magnetize in another direction
B) demag then remag in the desired direction
130
Cold working indications will:
A) not reappear is demagnetized then retested
B) not reappear if retested after stress relieving
C) not reappear if retested in the opposite direction
B) not reappear if retested after stress relieving
131
The negative magnetizing force required to reduce the residual flux density in a part to zero after saturation is called:
A) residual force
B) coercive force
C) demagnetizing field strength
D) null force
B) coercive force
132
A long defect, parallel to the longitudinal axis of a bar and caused by blowholes, cracks or tears introduced in earlier processing and elongated in the direction of rolling or forging is called:
A) a seam
B) a forging lap
C) a lamination
D) a cold shut
A) a seam
133
A burst is what type of discontinuity?
A) inherent
B) processing
C) service
D) all of the above
B) processing
134
Bursts usually have the following characteristics:
A) appear as smooth indentations on metal surfaces
B) are cavities varying in size from wide open to very tight, usually parallel with the grain
C) are extremely thin and flat, generally aligned parallel to the work surface of the material
D) are three dimensional discontinuities having smooth internal surfaces and generally located close to the surface of the worked material
D) are three dimensional discontinuities having smooth internal surfaces and generally located close to the surface of the worked material
135
In a rolling mill, flattening and elongation of metal is accomplished by:
A) tensile stresses
B) bending stresses
C) primarily compressive stresses
D) high frequency cyclic loads
C) primarily compressive stresses
136
A metal forming operation which allows three dimensional controls over the shape of the product is:
A) rolling
B) extruding
C) forging
D) all of the above
C) forging
137
A forming operation which will result in the greatest dimensional accuracy is:
A) cold rolling of sheet
B) hot rolling of sheet
C) cold rolling of bars
D) forging
A) cold rolling of sheet
138
A flaw which can resemble a cold shut is:
A) an undercut in a weld
B) a hot tear in a casting
C) a blowhole in a casting
D) a forging lap
D) a forging lap
139
Increasing test sample temperature normally:
A) increases electrical resistivity
B) decreases electrical resistivity
C) does not change electrical resistivity
D) increases magnetic permeability
A) increases electrical resistance
140
Cold working steel or aluminum results in a decrease in:
A) ductility
B) hardness
C) strength
D) all of the above
A) ductility
141
A manufacturing process based on plastic flow is:
A) welding
B) casting
C) forging
D) all of the above
C) forging
142
A steel casting suitable for working or remelting is called:
A) a bloom
B) a billet
C) an ingot
D) a slab
C) an ingot
143
With a forging hammer the striking force is imposed on the work metal by:
A) the lower die only
B) the upper die only
C) both dies moving in opposite directions
D) both B and C
B) the upper die only
144
The middle portion of the molding flask is called a:
A) cope
B) drag
C) cheek
D) separator
C) cheek
145
In a mold, the runner connect:
A) the pouring basin to the sprue
B) the down gate to the riser
C) the spruce to the ingate
D) the pouring basin to the mold cavity
C) the sprue to the ingate
146
Hot working an ingot may produce a product which has:
A) fewer defects than in the original ingot
B) more defects than in the original ingot
C) the same number of defects as in the original ingot
D) any of the above may be correct depending on the circumstance
D) any of the above may be correct depending on the circumstance
147
Cold shuts are most likely to be found in:
A) extrusions
B) forging
C) castings
D) sintered parts
C) castings
148
Aircraft turbine blades are usually processed by:
A) investment casting
B) shell mold casting
C) green sand casting
D) dry sand casting
A) investment casting
149
When thick and thin casting sections are adjacent to each other, what discontinuity may result?
A) porosity
B) inclusions
C) shrinkage
D) core shift
C) shrinkage
150
Which of the following is not normally associated with a casting?
A) segregation
B) core shift
C) misrun
D) bursts
D) bursts
151
Which of the following is identified as a casting insert?
A) Chaplet
B) mold
C) gate
D) riser
A) chaplet
152
A method commonly used to removed a number of flaws in an ingot prior to forming is:
A) cropping
B) heat treating
C) welding
D) sand blasting
A) cropping
153
The principle purpose of risers in molds is to:
A) feed the castings as the metal shrinks
B) let air escape from the mold
C) ensure impurities will remain outside the casting
D) favour directional solidification
A) feed the castings as the metal shrinks
154
An inherent defect formed prior to completion of solidification of the casting because of restricted contraction is called a:
A) hot tear
B) shrinkage
C) burst
D) cold shut
A) hot tear
155
Most manufacturing defects in a tube are:
A) axial in direction
B) circumferential in direction
C) on the outside of the tube
D) subsurface
A) axial in direction
