MT GINZEL BRO 151-300 Flashcards
1
Q
- When A.C. is used instead of D.C. for a head shot on a steel tube, the field
on the inside surface of the tube is
A. much less
B. much more
C. nearly the same
D. both are exactly zero
A
D. both are exactly zero
2
Q
152.The best way to determine magnetizing current required for irregularly shaped
pieces is
A. length to diameter ratio equations
B. 40 amps per mm of part thickness
C. empirically (trial and error)
D. finite element analysis
A
C. empirically (trial and error)
3
Q
- When using the prod method of MPI, defects are normally looked for
A. between the prods
B. under the prods
C. in circles about 4” (100mm) radius from the prods
D. in all of the above locations
A
A. between the prods
4
Q
- In order to maintain the same field strength at the midpoint of prods spaced 8
inches apart as was had with a 6 inch spacing you must
A. increase the magnetizing current
B. decrease the magnetizing current
C. use D.C. instead of A.C.
D. use larger diameter prod electrodes
A
A. increase the magnetizing current
5
Q
- Which is not a consideration when choosing current type to use for prod
inspection methods of MPI?
A. particle mobility
B. safety
C. power consumption
D. heating effects on equipment
A
B. safety
6
Q
- Capacitive discharge methods of producing a magnetizing current do so for only
a short duration.
A. typically 1 to 2 seconds
B. typically 0.5 to 1 seconds
C. typically 10 to 100ms
D. typically 5 to 55 µs
A
C. typically 10 to 100ms
7
Q
- Precracked magnetic steel plates are an effective means of
A. qualitative analysis of MPI bath concentrations
B. quantitative analysis of MPI bath concentrations
C. calibrating ammeters on MPI bench units
D. sizing unknown MPI indications
A
A. qualitative analysis of MPI bath concentrations
8
Q
- Typical pocket sized magnetic field indicators are used to measure
A. magnetizing force in a coil
B. external residual fields
C. internal residual fields
D. circular field strength during current flow
A
B. external residual fields
9
Q
- A low cost rugged tool used to measure residual magnetic field strength of
ferromagnetic parts is a
A. residu-meter
B. shunt meter
C. magnetic field indicator
D. Helmholtz coil
A
C. magnetic field indicator
10
Q
- A good magnetic field indicator (MFI) should have which characteristic?
A. rugged supports to prevent damage to the pointer needle
B. not be easily demagnetized by strong external fields
C. not induce magnetic poles of the parts they test
D. all of the above
A
D. all of the above
11
Q
- Excessive background in wet fluorescent MPI testing results from
A. excessive current density
B. excessive particle density
C. excessive blacklight intensity
D. both a and b
A
D. both a and b
12
Q
- The standard steel ring 7/8” thick having a 1 1/4” diameter central hole and
twelve 0.007” diameter holes arranged with increasing depth from the outside
edge of the ring is called a(n)
A. annular ring
B. Ketos ring
C. ASME ring
D. DIN ring
A
B. Ketos ring
13
Q
- Probability of seeing a wet fluorescent MPI indication
A. increases with increasing blacklight intensity
B. increases with decreasing white light background
C. increases with decreasing blacklight intensity
D. both a and b
A
D. both a and b
14
Q
- Although settling time prior to measuring wet fluorescent magnetic particle
concentration is now increased to 1 hour for most standards, complete settling
usually takes
A. 15 minutes
B. 30 minutes
C. 2 hours
D. 24 hours
A
D. 24 hours
15
Q
- When viewing the oil carrier of wet fluorescent particles (ie. the liquid
without the particles) under blacklight it usually has a _________ tint.
A. yellowish
B. bluish
C. yellow/green
D. reddish
A
B. bluish
16
Q
- The purpose of adding an antifoaming agent to wet MPI bath is to
A. reduce suds resulting from agitation
B. eliminate phosphates for environmental protection
C. prevent fluorescent material from disbonding from the oxides
D. all of the above
A
A. reduce suds resulting from agitation
17
Q
- Indications from medium to deep surface breaking seams found using A.C. MPI
A. are not possible to find
B. usually look alike
C. require extra large particles
D. form double indications
A
B. usually look alike
18
Q
- Fastest particle settlement in an MPI bath would occur for
A. small dense particles in a low viscosity liquid
B. small dense particles in a high viscosity liquid
C. larger dense particles in a low viscosity liquid
D. all of the above would settle about the same rate due to the Bernoulli
effect
A
C. larger dense particles in a low viscosity liquid
19
Q
- MPI indication width tends to increase for increasing
A. defect width
B. defect depth
C. magnetizing current strength
D. all of the above
A
D. all of the above
20
Q
- Because in general, there exists a direct relationship between indication
width and seam (defect) depth, a minimum magnetizing current level can be set
to
A. maintain uniform indication widths
B. detect significant flaws
C. both a and b
D. none of the above
A
B. detect significant flaws
21
Q
- Very fine MPI particles which fall into a crack opening can cause the flux
lines to remain in the part, this could result in
A. over estimating crack depth
B. over estimating crack length
C. missing the crack altogether
D. missing the crack all together if nonfluorescent particles are used
A
D. missing the crack all together if nonfluorescent particles are used
22
Q
- When lighting requirements are specified for a blacklight viewing of
fluorescent MPI, 20 lux white light intensity is
A. a recommended maximum
B. a recommended minimum
C. only a rough estimate
D. must be strictly met to ensure visibility of indications
A
A. a recommended maximum
23
Q
- What method is used to ensure proper magnetization levels are used?
A. formulae (rules of thumb)
B. test pieces
C. gauss/tesla meter
D. all of the above
A
D. all of the above
24
Q
- An advantage of MPI over LPI (Liquid Penetrant Inspection) is that ___________
using MPI.
A. ceramics can be tested
B. ferromagnetic materials can be tested
C. coated surfaces can be tested
D. it is always more environmentally friendly
A
C. coated surfaces can be tested
25
Q
- The difference between magnetic particle testing and magnetic flux leakage
testing is
A. the type of sensor used to detect fields
B. the type of magnetizing current used
C. the thickness of part that can be tested
D. none, they are exactly the same
A
A. the type of sensor used to detect fields
26
Q
- The “standard depth of penetration” resulting from the skin effect is caused
by
A. hysteresis
B. alternating current
C. direct current
D. Hall detectors
A
B. alternating current
27
Q
- To understand magnetic particle indication formation you should consider
A. discontinuity parameters
B. magnetic field parameters affecting the external flux leakage
C. how the magnetic particles react to passing through the leakage fields
D. all of the above
A
D. all of the above
28
Q
- The main purpose of a ferrite core in the coil type flux sensitive devices for
magnetic field testing is
A. reduction of electrical noise
B. to amplify the flux density
C. enhancement of the Hall effect
D. all of the above
A
B. to amplify the flux density
29
Q
- In addition to flux density amplification, ferrite cores in coil type flux
sensitive devices provide
A. support for the wire turns
B. minimizing of detrimental eddy current effect
C. both a and b
D. no useful purpose
A
C. both a and b
30
Q
- The crystals used in Hall detector type flux sensitive devices are
A. piezoelectric
B. pyroelectric
C. magnetostrictive
D. semiconductors
A
D. semiconductors
31
Q
- The main advantage of the Hall detector as a flux sensing device is
A. the small size of its active area
B. the low voltage required to run it
C. its direct readout of field
D. its ability to be used in both northern and southern hemispheres
A
A. the small size of its active area
32
Q
- Which materials are not used to make wet method particles for MPI testing?
A. finely divided iron
B. red iron oxide
C. black iron oxide
D. brown iron oxide
A
B. red iron oxide
33
Q
- The main disadvantage of a Hall detector as a flux measuring device is
A. its small size
B. variability between units
C. high cost per unit
D. poor temperature characteristics
A
B. variability between units
34
Q
- A ferro-probe (or Foerster microprobe) has a high frequency alternating
current in a coil mounted on a _______ core.
A. ferrite
B. diamagnetic
C. hard
D. paramagnetic
A
A. ferrite
35
Q
- Most non-fluorescent magnetic particles used in the wet method are
A. red iron oxide
B. unpigmented ferromagnetic iron oxides
C. fluorescent particles viewed without a blacklight
D. not reusable
A
B. unpigmented ferromagnetic iron oxides
36
Q
- For a given mass of fluorescent magnetic particles, 60µm sized particles would
be more visible by containing more fluorescent pigment than 125µm particles.
The reason for this is the smaller particles
A. less binding resin is needed
B. have a stronger chemical affinity for fluorescent pigments
C. have more surface area
D. all of the above
A
C. have more surface area
37
Q
- Which is not an advantage of oil based vehicles versus water based vehicles of
wet magnetic particles?
A. low corrosivity to ferrous alloys
B. low fire hazard
C. low electrical hazard
D. reduced risk of causing hydrogen embrittlement
A
B. low fire hazard
38
Q
- Which is not an advantage of water based vehicles versus oil based vehicles of
wet magnetic particles?
A. cost
B. speed of indication formation
C. lower electrical hazard
D. lower fire hazard
A
C. lower electrical hazard
39
Q
- When fine fluorescent magnetic particles are seen floating on the surface of
their water carrier like dust and no amount of mixing disperses them it
indicated
A. particle breakdown
B. insufficient or lack of wetting agent
C. excessive pump speed
D. the particles require demagnetization
A
B. insufficient or lack of wetting agent
40
Q
- Rust inhibitors placed in MPI water baths
A. provide only short term corrosion protection
B. are neutralized by fluorescent particles
C. double as antifoaming agents
D. all of the above
A
A. provide only short term corrosion protection
41
Q
- Mineral seed oil is sometimes added to a part after MPI testing with water or
oil based baths to provide
A. a demagnetizing effect
B. wash off excess magnetic particles
C. both a and b
D. longer term rust prevention
A
D. longer term rust prevention
42
Q
- When preparing a bath from dry concentrated MPI particles, in either oil or
water vehicle, if the tank is not equipped with a re-circulation pump uneven
distribution resulting from hand stirring can be avoided by
A. premix the quantity into a paste in a blender or small container before
adding to the bath
B. presoak the correct quantity in wetting agent or emulsifier
C. mounting an egg-beater on the tank
D. wrapping 3 turns of coil around the tank and applying maximum A.C. to the
coil when adding the powder
A
A. premix the quantity into a paste in a blender or small container before adding to the bath
43
Q
- Water used in preparing a water based MPI bath
A. must be de-aerated
B. must be demineralized
C. both a and b
D. can be straight tap water provided it is free from dirt particles
A
D. can be straight tap water provided it is free from dirt particles
44
Q
- The best way to control oil contamination of MPI baths is
A. use only oil for bath vehicles
B. effective precleaning of parts
C. organic osmotic type filters
D. inorganic micron sized filters
A
B. effective precleaning of parts
45
Q
- Settling volume determination used to establish MPI bath particle
concentrations usually uses which implement?
A. a pipette
B. a centrifuge tube
C. a ph meter
D. a mass indicator (triple beam balance)
A
B. a centrifuge tube
46
Q
- Bath concentrations for magnetic particle testing are usually specified as
having
A. a maximum value
B. a minimum value
C. a range of values
D. the same values for visible and fluorescent particles
A
C. a range of values
47
Q
- The practical upper limit temperature of the part surface performing MPI on a
part using a water vehicle is
A. 20°C.
B. 80°C.
C. 100°C.
D. 212°C.
A
C. 100°C.
48
Q
- The result of vibrating a sample of magnetic particle bath being tested for
concentration is to
A. increase setting speed
B. decrease apparent concentration by compaction
C. increase apparent concentration by fluffing
D. none of the above
A
B. decrease apparent concentration by compaction
49
Q
- The source of contaminants that can cause erroneous concentration readings for
MPI baths is
A. dirt from the test piece
B. dirt form the atmosphere
C. salts precipitating from hardwater
D. all of the above
A
D. all of the above
50
Q
- Blacklight intensity in post 1990 specifications nearly always quote minimum
irradiance in
A. lux
B. footcandles
C. candela
D. µW/cm²
A
D. µW/cm²
