MPI EMC Flashcards
(QUESTION #3) When two pieces of steel rub against each other and either or both are in a magnetized condition, an indication is some-
times formed when magnetic particles are applied. These indications are scrawl-like, ranging from very sharp to fuzzy.
This is called (check one)
a. cracks
b. constriction
c. cold working
d. magnetic writing
d. magnetic writing
(4) Indications caused by leakage fields due to internal splines, keyways, and drilled holes close to a test surface are
-defects
-nonrelevant
-magnetic writing
-boundary zones
nonrelevant
(5) Sub-surface defect indications usually appear
-sharp and distinct
-sharp and wide
-wide and fuzzy
-high and loosely held
-wide and fuzzy
(QUESTION #1) Place a check mark next to each material listed below which can be examined by the magnetic praticle method.
a. medium alloy steels
b. carbon steels
c. aluminum g. lead
d. magnesium
e. brass-copper
f. bronze
g. lead
h. ferro magnetic metals
a. medium alloy steels
b. carbon steels
h. ferro magnetic metals
(9) In considering demagnetization, which residual field is most objectionable?
a. longitudinal
b. circular
a. longitudinal
(10) Which residual field is most difficult to demagnetize?
a. longitudinal
b. circular
b. circular
(11) The amount of amperage used for magnetic particle inspection using the dry, prod method is based on:
a. thickness of part
b. distance between the prods
c. diameter
d. total length of part
b. distance between the prods
(12) Which is the most sensitive, continuous method or residual method?
continuous method
(13) Which brings out surface indications most clearly?
a. A.C.
b. D.C
a. A.C.
(14) How is the inside diameter of a cylinder best magnetized?
a. head shot
b. prods at either end
c. central conductor placed between contact heads
d. cylinder placed crosswise in solenoid
c. central conductor placed between contact heads
(15) The space within and surrounding a magnetized part or conductor carrying a current is known as:
a. saturation point
b. magnetic field
c. ferromagnetic
d. paramagnetic
b. magnetic field
(16) Any mass of iron, steel, or material capable of attracting other like masses is known as a ____
magnet
(17) Coercive force is a material which attracts other like materials when energized with electric current. True or false
false
(18) Permeability is the ease with which a metal or metallic part can be magnetized.
true or false?
true
(19) A metal that is easy to magnetize is said to have high permeability.
true or false?
true
(20) A metal that is difficult to magnetize is said to have high permeability.
true or false
false
(23) The areas on a magnetized part from which the magnetic field is leaving or returning into the part is called:
a. salient points
b. magnetic poles
c. defect
d. field
c. defect
(24) The property of magnetic metal to keep or retain a magnetic field after the magnetizing current is removed is called:
a. saturation point
b. retentivity
c. diamagnetism
d. bipolar magnetism
b. retentivity
(25) The strength of a magnetic field is known as:
a. flux density
b. ferromagnetic
c. magnetic poles
d. coercive force
a. flux density
(26) A sharp well defined indication is most likely to be:
a. sub-surface defect
b. surface defect
b. surface defect
(29) The defect indication is strongest when the magnetic field is at a 90° angle to the defect.
true or false?
true
(30) What group of materials is repelled by magnets?
a. paramagnetic
b. ferromagnetic
c. fluxematic
d. diamagnetic
d. diamagnetic
(31) What group of materials is most strongly affected by magnetism and may be inspected by magnetic particle inspection?
a. diamagnetic
b. alloys
c. ferromagnetic
d. nickel based metals
c. ferromagnetic
(32) 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 magnetization?
a. circular
b. longitudinal
c. transverse
d. continuous·
b. longitudinal
(33) 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. circular
(37) Give two causes of distorted fields.
- differences in contact pressure
- differences in surface or internal resistance
- irregularities in configuration o(part
- design of magnetizing equipment or application
(39) 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. amperage applied multiplied by number of turns in coil
(41) 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 subtance with good capillary action
d. metal shavings and particles
b. finely divided ferromagnetic particles of high permeability and low retentivity
(43) 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
c. wet method
(44) Inspecting a part by magnetizing then applying the medium is called (check one}
a. continuous method
b. wet method
c. residual method
d. dry method
c. residual method
Inspecting a part by applying the suspension while the current is flowing is called (check one)
a. continuous method
b. dry method
c. residual method
d. demagnetization method
a. continuous method
The flux density is always greatest (check one}
a. just after the current is removed
b. during the maximum current flow
b. during the maximum current flow
(49) A sharp variation in the permeability of material being inspected causing a magnetic particle indication is called a (check
one)
a. defect
b. discontinuity
c. nonrelevant indication
d. false indication
b. discontinuity
(50) A discontinuity which will affect the service life of the part being inspected and is detrimental to its quality, appearance
or performance is called a (check one)
a. nonrelevant indication
b. defect
c. scrap
d. magnetic pole
b. defect
