EMC MT Flashcards
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
Steels that contain more than 0.30 percent carbon, if welded, are prone to which type of
discontinuity?
a) Heat affected zone cracking
b) Porosity
c) Incomplete fusion
d) Slag formation
a) Heat affected zone cracking
- 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.
- 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
Where is the most logical place, on a casting, to look for discontinuities?
a) on the top surface
b) on the bottom surface
c) at internal surfaces
d) at junctions between light and heavy sections
d) at junctions between light and heavy sections
- What is the cause of cracks in the heat-affected zone?
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
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
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
The strength of a circular magnetic field is not diminished by ________ of a part:
a) permeability
b) diameter
c) length
d) any of the above
c) length
Which of the following provides the NDT inspector with a brief outline of the steps to perform a test
on a specific item?
a) code
b) standard
c) procedure (instruction)
d) specification
c) procedure (instruction)
The width of a magnetic particle indication:
a) indicates flaw depth
b) is always wider than the actual flaw opening
c) is equal to the height of particle indication
d) is determined by the angle of repose
b) is always wider than the actual flaw opening
When the central conductor MPI method is used to inspect a ring shaped object, or short cylinder:
a) only inside diameter surface flaws can be found
b) only outside diameter surface flaws can be found
c) both inside and outside surface and subsurface flaws can be found if the wall thickness is
not too great
d) none of the above, central conductors cannot be used for ring shaped objects
c) both inside and outside surface and subsurface flaws can be found if the wall thickness is
not too great
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
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 A.C. yoke
b) increasing leg spacing
c) reducing magnetizing current
d) using a pie gage
a) using an A.C. yoke
The best way to demagnetize a long tube would be:
a) reversing D.C. with a central conductor
b) pulsating A.C. with a central conductor
c) a portable yoke
d) passing the tube through an A.C. coil
a) reversing D.C. with a central conductor
To reduce the discomfort of eye fatigue when performing fluorescent MPI you can:
a) take breaks at regular intervals
b) wear yellow green tinted glasses (of the appropriate filtering ability)
c) both a and b
d) increase dark adaption time
c) both a and b
Nonrelevant indications due to residual local poles interfere with magnetic particle testing. For a
successful examination one should?
a) Magnetize in another direction
b) Demagnetize then remagnetize in the desired direction
c) Use lower amperage
d) Use more amperage
b) Demagnetize then remagnetize in the desired direction
If a discontinuity is shallow and broad like a scratch, the flux lines may stream line below the
discontinuity. This will result in:
a) a false indication
b) a non-relevant indication
c) a sub-surface indication
d) a lack of indication
d) a lack of indication
