MPI 2 Questions Flashcards
1
Q
Which of the following types of magnetic field exhibits no external flux leakage in the absence of discontinuities?
-Vectored
-Longitudinal
-Circular
-All of the above exhibit external flux leakage
A
Circular
2
Q
What is the value given in SI unites for the permeability of free space?
- 1
- 0.72 Tesla
- 5 Gausss
- 4 x 10-7 Henries/M
A
4 x 10-7 Henries/M
3
Q
When a ferromagnetic material becomes magentised under the influence of an increasing stronger magnetising force, which of the following occurs?
-Domains become larger and fewer in number
-Domains become smaller and fewer in number -Domains become smaller and greater in
-Domains become larger and greater in number
A
Domains become larger and fewer in number
4
Q
Which of the following would constitute a low reluctance preferential path?
-Non metallic inclusion
-Ferromagnetic particle
-Copper
-Air
A
Ferromagnetic particle
5
Q
When carrying out magnetic particle inspection, flux density is generated into the ferromagnetic material being inspected. One unit of flux density is the gauss. How many webers per square metre equal one gauss?
-0.72
-10^4
-2 x 1 0 - 6
-0.00072
A
10^4
6
Q
The right hand rule shows which of the following relationships?
-Electron flow from negative to positive with a magnetic field parallel to the current flow
-Current flow from negative to positive with a magnetic field perpendicular to the current flow
-Electron flow from positive to negative with a magnetic field parrallel to the current
-Current flow from positive to negative with a magnetic field peroendicular to the
current flow
A
Current flow from positive to negative with a magnetic field peroendicular to the current flow
7
Q
A ferromagnetic material with a steep initial curve will have which of the following properties?
-Low permeability
-Low coercivity
-High reluctance
-The material will have all of the above properties
A
Low coercivity
8
Q
When magnetising with alternating current, a lagging effect occurs where by the magnetic flux density within the metrial lags behind the applied magentising force. What is this phenomena called?
-Retentivity
-Reluctance
-Hysteresis
-Permeability
A
Hysteresis
9
Q
Direct induction will always generate which of the following types of magnetic field?
-Circular
-Longitudinal
-Vectored
-All the above could be generated
A
Circular
10
Q
The curie point is the temperature at which a ferromagnetic material will become paramagnetic and as such loose its high susceptibility to magnetisation. What is the curie point temperature for cobalt?
-770 Degrees Farenheit
-1130 Degrees Farenheit
-770 Degrees Celsius
-1130 Degrees Celsius
A
1130 Degrees Celsius
11
Q
The magnetic flux lines which flow through a bar magnet form closed loops but can be broken by which of the following?
- A change in permeability
- A non metallic inclusion
- A crack
- None of the above will cause a break in a flux line
A
None of the above will cause a break in a flux line
12
Q
The earth itself has a magnetic effect which can affect ferromagnetic materials. Which of the following best describes this magnetic effect?
-Mono-Polar
-Bi-Polar
-Multi-Polar
-Circular Magnetic Fields
A
Bi-Polar
13
Q
A fault in magnetised material will best be detected when it lies in which of the following directions?
-Parallel to the magnetic field
-Perpendicular to the magnetic field
-Parrallel to the magnetising current
-Perpendicular to the magnetising force
-Both parallel to the magnetic field and perpendicular to the the magnetising force
-Both perpendicular to the magnetic field and parrallel to the magnetising current
A
Both perpendicular to the magnetic field and parrallel to the magnetising current
14
Q
A change in which property of between the material being inspected and the discontinuity to be detected generates flux leakage?
-Conductivity
-Permeability
-Oxidisation
-Hysteresis
A
Permeability
15
Q
Which of the following materials would be considered to be have a permeability much greater than that of air?
-Aluminium
-Bismuth
-Zinc
-Gadolinium
-None of the above have a permeability much greater than air
A
Gadolinium
16
Q
Which of the following flux leakage curvatures will have the greatest attraction for magnetic particles?
-Low Curvature
-No Curvature
-Highly curved
-Curvature has no effect on magnetic particle attraction
A
Highly curved
17
Q
A discontinuity which generates flux leakage on the surface of a ferromagnetic material will have a high factor for which of the following properties?
-Permeability
-Reluctance
-Retentivity
-Both reluctance and retentivity
A
Reluctance
18
Q
Which of the following decribes a Hall Effect Element Sensor?
-Two coils placed mutually perpendicular
-A P-N junction within a semi-conductor
-Current carrying semi-conductor crystals
-Coils wound around cylindrical ferrite
A
Current carrying semi-conductor crystals
19
Q
Which of the following materials will have the largest relative permeability value?
-0.9% Carbon
- Nickel (99% annealed)
-Cobalt (99% annealed)
-Aluminium
A
Nickel (99% annealed)
20
Q
Which of the following is an advantage of three phase electricity over single phase electricity?
-More particle mobility especially when using dry powder
-Better detection of surface breaking faults due to skin effect
-Less current input per phase
-All of the above are advantages
A
Less current input per phase
21
Q
When using field flow magnetisation (solenoid heads) a reference standard whould be used with a known artificial discontinuity located where on the standard?
-At the centre of the cross section
-At a position one third along itself
-In the centre of the materials length
-None of the above should be used to evaluate field flow magnetisation
A
In the centre of the materials length
22
Q
For what reasons are laminated iron cores used for the production of AC electromagnetic yokes?
-They are easier to encapsulate in plastic
-Better efficiency in the generation of magnetic fields
-Solid iron would be too heavy
-Solid iron would not give the skin effect
A
Better efficiency in the generation of magnetic fields
23
Q
When using a threading bar (central conductor) to test a hollow tube, it needs to be placed where in relation to the tubes inner diameter for optimum inspection to be carried out?
-In the centre of the tube
-Adjacent to the inner circumference of the tube
-Adjacent to the outer circumference of the tube
-The conductor can be placed in any of the above positions
A
Adjacent to the inner circumference of the tube
24
Q
The output of power packs needed to magnetize forgings and castings too large to place in stationary units is in the range?
- 6 - 2 0 M A
- 0.25 - 3 KA
- 6 - 2 0 K A
- 0.25 - 3 MA
A
6 - 20 KA
25
When direct current is passed through a central conductor inserted through a hollow tubes at what point is the magnetic field intensity essentially zero?
-At the inner circumference of the tube
-At the exact centre of the threading bar
-On the surface of teh tube
-Both at the inner circumference of the tube and at the exact centre of the threading bar
At the exact centre of the threading bar
26
Under optimum conditions with dry powder for substances flaw detection, which of the following waveforms would best be used?
-Direct current
-Three phase rectified alternating current - full wave
-Alternating current
-Single phase rectified alternating current - half wave
Single phase rectified alternating current - half wave
27
Under optimum conditions magnetic particles used with the wet method are made from iron oxide rather than higer permeability iron. What are the reasons for this choice?
-Iron oxide is more dense than iron
-Iron oxide is less dense than iron
-Iron oxide falls out of suspension quicker than iron
-Iron falls out of suspension quicker than iron oxide
-Both Iron oxide is less dense than iron and Iron falls out of suspension quicker than iron oxide
Both Iron oxide is less dense than iron and Iron falls out of suspension quicker than iron oxide
28
The following is a standard definition, 'A small portable device containing artificial discontinuities used to determine when the correct magnetising conditions have been achieved.' Which of the following is correct?
-Flux meter
-Flux indicator
-Gauss meter
-Image quality indicator
Flux indicator
29
Which of the following techniques would best be used to detect circumferential faults in rings without damaging the parts surface in one shot?
-Direct induction between contract heads across diameter of ring
-A threading bar
-Induced current generating a toroidal magnetic field
-Magnetic flow across the diamter of ring
Induced current generating a toroidal magnetic field
30
Using 10 amps per mm diameter how much current is to be used to magnetise a bar 25 x 20 mm x 2 metres long on a bench unit using current flow?
-286 amps
-320 amps
-160 amps
-143 amps
286 amps
31
Magnetic particles form indications around flux leakages due to which of the following?
-Magnetism follows the path of most resistance -Iron particles are good conductors of electricity -Air has a higher reluctance than iron or iron oxide
-All of the above are true
Air has a higher reluctance than iron or iron oxide
32
Which of the following materials could be inspected using the residual technique due to the materials high retentivity?
-Low carbon steel
-Heat treated high carbon steel
-Austenitic stainless steel
-Ferritic stainless steel
Heat treated high carbon steel
33
With prods using half wave direct current, the magnetic field within the material is dependent on which of the following factors?
-Amount of current used
-The permeability of the inspected material
-The distance between prod tips when positioned on the chromed hard facing
-Both the amount of current used and the permeability of the inspected material
-All of the above
Both the amount of current used and the permeability of the inspected material
34
Which of the following techniques is most likely to be used when a permanent record of the inside of a threaded bolt hole is required?
-Strippable lacquer
-Photography
-Magnetic Rubber
-Any of the above may be used
Magnetic Rubber
35
If two magnetic fields of equal intensity are induced into a ferromagnetic material at 90 degrees to each other in the longitudinal and transverse directions, which of the following faults could be detected?
-Faults only at 45 degrees
-Longitudinal faults only
-Transverse faults only
-Faults lying in a position 45 degrees in either direction from a direction at 45 degrees from the longitudinal direction
Faults lying in a position 45 degrees in either direction from a direction at 45 degrees from the longitudinal direction
36
Why would a photometer be used when carrying out fluorescent magnetic particle inspection?
-To measure the black light given off from a UV-A lamp
-To measure radiation between 320 nM - 400 nM
-To measure radiation between 400 nM - 700 nM
-None of the above
To measure radiation between 400 nM - 700 nM
37
Photopic vision refers to vision used when carrying out which type of inspection?
-Non fluorescent inspection
-Fluorescent inspection
-Dry powder inspection
-All of the above
-Both Fluorescent inspection and dry powder inspection
Non fluorescent inspection
38
If the levels of electric current used to magnetize ferromagnetic material are greatly exceeded, what phenomena can occur when magnetic particles are applied?
-The particles are forced off the parts surface due to vibrational impingement
-The particles are forced together around faults showing an indication much larger than
the fault below
-The particles are held over the entire surface giving an overall background which may be confusing
-The part will very quickly melt
The particles are held over the entire surface giving an overall background which may be confusing
39
Which of the following would be used to render water a suitable carrier fluid for use in the wet
magnetic particle technique?
-De-wetting agent
-Rust inhibitor
-Foaming agent
-All of the above could be used
Rust inhibitor
40
Why do prod tips need to be kept clean and free from contaminants?
-The contamination reduces the resistance so increasing current flow
-Clean prod tips have less chance of arcing
-Clean prods conduct current through scale much better
-The increase in resistance with dirty prods reduces the current output
-Both clean prod tips have less chance of arcing and the increase in resistance with dirty prods reduces the current output
Both clean prod tips have less chance of arcing and the increase in resistance with dirty prods reduces the current output
41
For one person to use prods unaided which of the following would be the most suitable approach?
-Hold both prods in one hand with the detaching medium in the other
-Use the residual technique as the detecting medium can be applied after the magnetizing force
-Use a magnetic leech attachment to one prod with the other in one hand and the detecting medium in the other
-Prods should not be used by one person due to safety precautions
Use a magnetic leech attachment to one prod with the other in one hand and the detecting medium in the other
42
Subjecting a ferromagnetic material to a magnetising force which reserves in a polarity whilst at the
same time remains the same strength, has what effect?
-Demagnetization
-Magnetization
-None of the above
-Either demagnetisation or magnetization
Magnetization
43
For the highest possible sensitivity when using the continuous method which of the following application techniques should be used?
-Apply current whilst applying wet magnetic ink by spray
-Apply current whilst part is immersed in wet ink followed by removal whilst current still
flows
-Apply current whilst part is immersed in wet ink. Stop flow of current whilst removing
-All the above give the same sensitivity
Apply current whilst part is immersed in wet ink followed by removal whilst current still flows
44
Which of the following processes could have the effect of reducing the gradient of the B/H curve for a particular ferromagnetic material?
-Cold rolling
-Subjecting the material to stress
-Annealing
-Work hardening
Annealing
45
An arrangement consisting of 2 C-shaped yokes connected together at right angles will give rise to which of the following when testing a weldment?
-A circular magnetic field
-A longitudinal magnetic field to detect longitudinal faults
-A vectored field to detect longitudinal faults only
-A vectored field which will detect both transverse and longitudinal faults
A vectored field which will detect both transverse and longitudinal faults
46
Which type of surface condition would be most conducive to inspection using multi direction magnetisation by switching from one field to another at 90 degrees to the first?
-Rough as cast
-Brightly machined
-Electro polished
-Surface finish has no influence on particle build up using multi -directional magnetisation
Rough as cast
47
Why is demagnetization carried out prior to magnetic particle inspection in areas such as the aerospace industry?
-There is the possibility of a pre-existing field which will cause an actual magnetic field within the tested material in an unfavourable direction
-The pre-existing field may nullify the applied field
-Demagnetization is not carried out prior to inspection
-There is the possibility of a pre-existing field which will cause an actual magnetic field within the tested material in an unfavourable direction and the pre-existing field may nullify the applied field
There is the possibility of a pre-existing field which will cause an actual magnetic field within the tested material in an unfavourable direction and the pre-existing field may nullify the applied field
48
When using a central conductor to magnetize a ferromagnetic tube magnetic field strength is greatest at what point within the system?
-Outside surface of threading bar
-Outside surface of tube
-Inside surface of tube
-At none of the above positions
Inside surface of tube
49
What is the difficulty when inspecting complex parts with differing cross-sections?
-Under magnetization of large sections
-Over magnetization of small sections masking certain areas
-Demagnetization prior to inspection
-Both under magnetisation of large sections and over magnetisation of small sections masking certain areas could be correct
Both under magnetisation of large sections and over magnetisation of small sections masking certain areas could be correct
50
When photographing magnetic particle indications, highest definiton is obtained when which of the following films are used?
-Slow film - coarse grain
-Slow film - fine grain
-Fast film - coarse grain
-Fast film - fine grain
Slow film - fine grain
51
Which of the following carrier fluids used with wet magnetic inks will have the smallest change in viscosity between the temperatures of 0 degrees celsius and 50 degrees celsius?
-Water
-Oil
-Kerosene
-All will react in the same way to changes in temperature
Water
52
Permanent magnets can be made out of which of the following materials?
-Aluminium, Cobalt, and Nickel
-Molybdenum and Aluminium
-Copper, Nickel and Iron
-Copper and Aluminium
-Both Aluminium, Cobalt and Nickel, and Copper, Nickel and Iron
-Both Molybdenum and Aluminium, and Copper and Aluminium
Both Aluminium, Cobalt and Nickel, and Copper, Nickel and Iron
53
When attempting to demagnetize with an electromagnetic yoke, which of the following will be most effective?
-Use a DC yoke and withdraw whilst switched off
-Use an AC yoke and withdraw whilst energized
-Use a DC yoke and withdraw whilst energized
-Use an AC yoke and withdraw whilst switched off
-Use a single pole AC electromagnet and withdraw whilst energised
Use an AC yoke and withdraw whilst energised
54
As the magnetizing force acting upon a ferromagnetic part increases what will be the effect on the detection of faults parallel to the magnetic field?
-Substantial increase in the possibility of detection even up to saturation
-Substantial increase in the possibility of detection upto approximatley two thirds
saturation
-No increase in the possibility of detection even up to saturation
-None of the above are correct
No increase in the possibility of detection even up to saturation
55
Which of the following magnetic fields will have the most effect on other material and equipment affected by external flux leakage and as such will more than likely require demagnetization?
-Circular
-Circumferential
-Longitudinal
Longitudinal
56
When using an encircling coil to longitudinally magnetize a length of bar material, which of the following factors are important when calculating the amount of current to satisfactorily magnetize the bar?
-Cross section of bar
-Length of bar
-Diameter of bar
-All the above
-Only the length of bar and diameter of bar
All the above
57
Which of the following would not be a reason why demagnetisation would be required after
magnetic particle inspection?
-The part is to be further machined
-The part is to be heat treated below the curie point
-The part is to be plated afterwards
-The part is to be welded by automatic equipment afterwards
The part is to be heat treated below the curie point
58
If a current of the same amperage is passed through two magnetic conductors, one of which is twice the diameter of the other, which of the following statements is true?
-The magnetic field strength on the surface of the smaller bar is weaker than on the surface of the larger bar
-The magnetic field strength on the surface of the larger bar is stronger than on the surface of the smaller bar
-The magnetic field strength at the centre of the small bar is stronger than at the centre of the large bar
-The magnetic field strength at the centre of the small bar is weaker than at the surface of the large bar
-The magnetic field strength on the surface of the smaller bar is stronger than on the surface of the smaller bar
The magnetic field strength on the surface of the smaller bar is stronger than on the surface of the smaller bar
59
If an AC (RMS) type ammeter reads 700 amps, how much peak current is actually flowing?
- 700 amps
- 490 amps
- 1400 amps
- 987 amps
987 amps
60
When carrying out magnetic particle inspection on plated parts that have been ground why should some form of direct current be used?
-To inspect the thickness of the non magnetic plating
-To detect subsurface faults within the body of the plated material
-To detect grinding cracks in the parent material below the plating
-To detect cracks on the plated surface
To detect grinding cracks in the parent material below the plating
61
Non-relevant indications which may occur when inspecting ferromagnetic parts which have been stressed beyond the yield point may be due to the presence of?
-Bend cracks
-Luder lines
-Work hardening
-Non metallic inclusions
Luder lines
62
Magnetic writing indications produced where an electromagnetic yoke leg has been placed can give indications on further processing called?
-False
-Non relevant true
-Relevant true
-Both False and Non relevant true could be correct
Non relevant true
63
Stress corrosion cracking which occurs predominantly in a direction perpendicular to the tensile stress whilst also in a corrosive atmosphere have which of the following characteristics?
-Transgranular
-Intergranular
-Ductile fracture
-Either transgranular or intergranular
Either transgranular or intergranular
64
As the depth of a detectable flaw increases below the surface the powder pattern will become which of the following?
-Clear and narrow
-Diffuse and wider
-Clear and wider
-Diffuse and narrow
Diffuse and wider
65
In an attempt to depth a crack found with magnetic particle inspection which other method of NDT
could be used?
-Liquid penetrant
-Leak testing
-Grinding to clear
-Ultrasonics
Ultrasonics
66
A large turbine gear shaft is in the preliminary stages of machining, when periodic inpsection reveals a rather gross crack. Which of the following would be the best way to proceed?
-Grind a notch across the crack to size the depth and determine if the entire crack can be removed within dimensional tolerances
-Carry on and machine the part hoping that the crack will clear
-Fully gring out the crack to determine the depth all along the length to make sure it
can be removed within dimensional tolerances
-Scrap the part as any discontinuity will cause a stress concentration even if it was eventually removed within tolerance
Fully gring out the crack to determine the depth all along the length to make sure it can be removed within dimensional tolerances
67
Which of the following faults would not be detected on a sand casting which has been machined after the initial casting process?
-Shrinkage crack
-Fatigue crack
-Blow hole
-Cold shut
-Unfused chaplet
Fatigue crack
68
Non metallic inclusions can also be found with magnetic particle inspection as well as cracks. This is due to a change in what property of the inclusion in relation to the parent materials?
-Conductivity
-Flux leakage
-Hysteresis
-Permeability
Permeability
69
A fault on the surface of a rolled bar is present due to blowholes elongating along the length of the bar. How would this fault be termed?
-Underfill
-Seam
-Roke
-Crack
Seam
70
The following is a description for the formation of magnetic particle indications when testing a weldment with HWDC to give the dry powder mobility. 'A very weak and not clearly defined indiction'. Which of the following would produce such indications?
-Subsurface crack
-Surface breaking porosity
-Subsurface porosity
-Surface breaking crack
Subsurface porosity
71
Metallurgical changes of the like which appear close to the centre of a cold chisel due to heat treatment may give rise to what type of indication?
-False
-False - non relevant
-True
-True - non relevant
-Both False - non relevant and True non - relevant are correct
True - non relevant
72
On completion of a butt weld after cooling the entire weld and HAZ is inspected with MPI revealing no faults. On subsequent inspection 48 hours later again with MPI prior to service conditions a linear indication is found within the HAZ running in the same direction as the weld bead. Which of the following is the most likely name for this fault?
-Hot crack
-Fatigue crack
-Cold crack
-The fault could be any of the above
Cold crack
73
The following is a description of a fault which occurred in four positions at 90 degrees to each other towrads one end of a cast steel tube on the outer periphery made by sand casting. The individual indications range in size but seem to indicate a linear circular fault which in once case is a circle. Which of the following best describes the fault?
-Cold shut
-Hot tear
-Unfused chaplet
-Porosity
-Both Cold shut and unfused chaplet
-Both Hot teat and porosity
Both Cold shut and unfused chaplet
74
Which of the following techniques would be considered to be the most sensitive for detection of surface breaking faults on materials with high retentivity if the length of time taken to cary out the inspection is of no consequence?
-Continuous - wet
-Residual - wet
-Continuous - dry
-Residual - dry
Residual - wet
75
When magnetic particles from a wet magnetic ink become stranded in drainage lines such as the toe of a weld when the carrier fluid drains away, what type of indication can build up?
-False indication
-True - non relevant indication
-True - relevant indication
-Crack - line indictaion
False indication
76
When using circular magnetization to check bar material an overall pattern of circular bands is observed with a bristling of the particles. What is this phenomena called?
-Fuzzing
-Gaussing
-Furring
-Under magnetisation
Furring
77
When using prods with HWDC to inspect a single V plate butt weld two slightly subsurface parallel lines were obsereved quite weak and poorly defined running in the direction of the weld. What is the most likely cause for these indications?
-Lack of root penetration
-Undercut
-Slag indications
-Cooling cracks
Slag indications
78
A very fine indication was observed on an inservice inspection of a rotating shaft in a pump at a sharp change in section and was originally considered to be non relevant. On subsequent inspection 6 months later it was observed that the indication had grown by nearly 25%. What is the most likely cause for this indication?
-Grinding crack
-Fatigue crack
-Stringer
-Inclusion propagation
Fatigue crack
79
Which of the following could give rise to true non-relevant magnetic particle indications?
-Areas of cold work
-Heavy rough machining
-Brazed joints
-Both areas of cold work and brazed joints
-All of them
All of them
80
Mag particle is a net exam method used for?
a. locating surface discontinuities
b. locating near surface discontinuities
c. both a and b
d. detecting material separation
c
81
Ferromagnetic material is:
a. strongly attracted by a magnet
b. capable of being magnetized
c. both a and b
d. not capable of being magnetized
c
82
The permeability of a material describes the:
a. ease with which it can be magnetized
b. depth of the magnetic field in the part
c. length of time required to demagnetize it
d. ability to retain the magnetic field
a
83
The retentivity of a material describes the:
a. ease with which it can be magnetized
b. depth of the magnetic field in the part
c. length of time required to demag
d. ability to retain the magnetic field
d
84
Why are magnetic particles available in different colours?
a. for the colour contrast with the part surface
b. to enhance the detection of the indications
c. both a and b
d. different colours are used with different magnetic flux values
c
85
Which of the following can be magnetized?
a. iron
b. nickel
c. cobalt
d. all the above
d
86
The magnetic field is strongest when the:
a. magnetizing voltage is flowing
b. magnetizing current is flowing
c. material exhibits high coercive forces
d. magnetizing current is not flowing
b
87
If a crack exists in a circular magnet, the attraction of mag particles to the crack is cause by:
a. coercive force
b. leakage field
c. Doppler effect
d. high reluctance at the crack
b
88
The unit usually used to denote flux density is the:
a. gauss
b. Henry
c. farad
d. ampere
a
89
Which statement is true when related to mag lines of force?
a. they never cross
b. they are most dense at the poles of a magnet
c. they seek the path of least resistance
d. all of the above
d
90
Mag flux lines which are parallel to a discontinuity produce:
a. strong indications
b. weak indications
c. no indications
d. fuzzy indications
c
91
A part is adaptable to magnetic particle inspection if:
a. it is attached to an electrostatic field
b. the material is ferromagnetic
c. the material is nonferrous
d. the material is an electric conductor
b
92
What rule describes the direction of the current flow (+ to -) when lines of mag force surround a conductor?
a. the left hand rule
b. the right hand rule
c. the flux rule
d. the reluctance rule
b
93
The magnitude of the residual mag field in a specimen is dependant on the:
a. L/D ratio (length to diameter)
b. strength of the applied magnetizing force
c. right hand rule
d. left hand rule
b
94
The proper number of ampere-turns for given test specimen is determined by:
a. its length
b. the material
c. both a and b
d. its diameter
c
95
A circular field may be induced into a specimen by:
a. direct induction (head shot)
b direct induction (prods)
c. central conductor
d. all the above
d
96
An electrical yoke produces:
a. a longitudinal field
b. a circular field
c. alternating fields
d. a swinging field
a
97
A coil around the part produces:
a. a circular field
b. a longitudinal field
c. either a or b depending on the type of current applied
d. an intermittent field
b
98
In longitudinal magnetization, the proper term for calculating magnetizing force is:
a. amperes
b. ampere-turns
c. watts
d. ohms
b
99
Magnetic lines of force:
a. travel in straight lines
b. form a closed loop
c. are randomly oriented
d. overlay in highly ferromagnetic materials
b
100
A magnetic particle build-up from a discontinuity is strongest when the discontinuity is oriented:
a. 180 degrees to the mag field
b. 45 degrees to the mag field
c. 90 degrees to the mag field
d. 90 degrees to the current flow
c
101
A specimen may be demagnetized by:
a. heat treatment above Curie temperature
b. an AC coil
c. reversing DC fields
d. all of the above
d
102
Which of the following is an advantage of the magnetic particle testing over penetrant testing?
a. it can detect surface discontinuities with foreign material imbedded in them
b. it is faster on individual parts
c. it can detect near-surface discontinuities
d. all of the above
d
103
The amount of amp used for mageticle particle inspection using the prod method is determined the:
a. type of material
b. distance between the prods
c. diameter of the part
d. total length of the part
b
104
The flux within and surrounding a magnetized part or around a conductor carrying caring a current is known as:
a. saturation point
b. magnetic field
c. ferromagnetic
d. paramagnetic
b
105
26 -The areas on a magnetized part from which the mag field is leaving or returning into the part are called?
a. salient points
b. defects
c. magnetic poles
d. nodes
c. magnetic poles
106
27. A metal that is difficult to magnetize is said to have:
a. high permeability
b. low permeability
c. high reluctance
d. low retentivity
b. low permeability
107
29. Why is it preferable to disassemble parts before magnetic particle inspection?
a. Makes all surface areas visible
b. Interfaces will create leakage fields which may confuse the inspection
c. It is usually easier to handle the disassembled parts
d. all the above
d. all the above
108
Sub-surface defect usually appear:
a. sharp and distinct
b. sharp and wide
c. wide and fuzzy
d. high and loosely held
c. wide and fuzzy
109
Which residual field is most difficult to damag?
a. long
b. circular
c. vector
d. binodal
b. circular
110
What technique is the most sensitive?
a. continuous
b. residual
c. interrupted
d. counter-current
a. continuous
111
35. Inspecting a part by magnetizing, removing the current flow, then applying the medium is called the:
a. continuous method
b. wet method
c. residual method
d. dry method
c. residual method
112
False indications are caused by magnetic particles being held to the part by which of the following means?
a. gravity
b. mechanical
c. both A and B
d. None
d. None
113
Which of the following is the most effective method for the detection of extremely deep-lying defects?
a. dry residual method
b. wet continuous method
c. wet residual method
d. dry continuous method
d. dry continuous method
114
39. What method provides greater sensitivity particularly in locating sub-surface discontinuities?
a. continuos
b. residual
c. circular
d. longitudinal
a. continuos
115
When mag a weld in two directions, and if the current used in the first direction is 750 amps and the current in the second direction is 400 amps, which of the following is true?
a. The part should be checked to see if demag between operations is necessary
b. No precautions should be taken before the second operation
c. This is not a valid technique
d. There is no need to magnetize a weld in two directions
a. The part should be checked to see if demag between operations is necessary
116
When there is absolutely no pattern or distribution of mag particles, the possible cause is that:
a. the material is nonmagnetic
b. the amp setting is too low
c. no current is being applied
d. any of the above
d. any of the above
117
What are 3 causes of non relevant indications?
a. Lack of fusion, change of section thickness, grinding cracks
b. Change of section thickness, very high amperage, drilled hole near the surface
c. Very high amperage, drilled hole near surface, blow holes
d. Drilled hole near surface, very high amperage, lack of fusion
b. Change of section thickness, very high amperage, drilled hole near the surface
118
Using the residual test method, a number of test parts are magnetized and laid on a rack prior to the application of mag particles. Why is it important that they do not rub or touch each other?
A. The is a possible loss of mag field
b. It may cause magnetic writing
c. It may damage the part
d. It makes parts hard to handle
b. It may cause magnetic writing
119
The point at which the magnetism in a material cannot be increased even though the magnetizing force continues to increase is known as the
a. salient pole
b. saturation point
c. residual point
d. remnant point
b. saturation point
120
Which type of current has a "Skin effect"?
a. AC
b. DC
c. half wave rectified
d. full wave rectified
a. AC
121
When using the wet method, why should a high velocity flow of wet method bath over surfaces following removal of the magnetizing current NOT be used?
a. It may wash away a fine or weakly held indication
b. not a problem
c. It may splash particles into eyes
d. None
a. It may wash away a fine or weakly held indication
122
Mag inspection is not a reliable method of detecting:
a. laps
b. deep seated cavities
c. cracks
d. seams
b. deep seated cavities
122
Residual mag inspection may be used when:
a. parts are irregular in shape
b. parts are highly retentive
c. parts are highly stressed
d. evaluating continuous method indications
b. parts are highly retentive
123
51. Which of the following will produce circular magnetism?
a. Passing current through a coil
b. placing the part in a solenoid
c. passing current through prods
d. yokes
c. passing current through prods
124
When using the wet continuous method, the flow of suspension from the hose should be shut off:
a. immediately after applying the current
b. immediately before applying the current
c. while the current is flowing
d. 30 seconds before applying the current
c. while the current is flowing
125
53. The strongest mag field in a coil is at the:
a. outside edge
b. inside edge
c. center
d. end
b. inside edge
126
To detect lengthwise defects on the inside diameter of hollow parts, you should:
a. pass current through it
b. magnetize with a coil
c. pass current through a central conductor
d. increase the amperage used
c. pass current through a central conductor
127
What equipment is used to determine if a part has been demagnetized?
a. a magnet on the part
b. a field meter
c. a survey meter
d. careful observation for clinging magnetic particles
b. a field meter
128
Which of the following is most often used for dry mag inspection?
a. full 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
129
An electric current through a copper wire
a. creates a mag field around the wire
b. creates mag poles in the wire
c. mag the wire
d. does not create a mag field
a. creates a mag field around the wire
130
Why should parts be cleaned after demagnetization?
a. to assure that the mag parts are removed
b. to prevent false indications
c. to save the solids of the suspension
d. to prevent cracking during heat treatment
a. to assure that the mag parts are removed
131
In the circular magnetization, the magnetizing force is expressed in amperes. What term is used to express magnetizing force longitudinal magnetization?
a. amperes
b. ampere-turns
c. consequent poles
d. volts
b. ampere-turns
132
A longitudinal surface crack in a circularly magnetize part will cause:
a. the magnetic field to die out
b. a decrease in permeability
c. magnetic leakage field
d. a current to flow
c. magnetic leakage field
133
In a mag test, assuming that all of the following are the in the same relative position in a small part, which would be the hardest to detect?
a. surface crack
b. near surface crack
c. scratch
d. seam
