Questions With Correct Answers
ferromagnetic material
A material that is strongly attracted to a magnetic field.
Diamagnetic material
A material that is repelled by a magnetic field
paramagnetic
slightly attracted to magnets
Is Demagnetized
When a ferromagnetic material reaches its Currie temperature the material is
Alloy, shape, and condition of the part
An important factor that must be considered when selecting a method of magnetization is the
Fixed positions, predominantly in One Direction
The magnetic domains in a permanent magnet are aligned in
Diamagnetic
Any material with a negative relative permeability that is slightly less than one is
Casting
Gas, hot tears, cold shuts, shrinkage cracks and sand inclusions are examples of defects resulting
from which of the following processes?
If the part is to be radiographed after magnetic particle inspection, residual magnetism may
interfere with the electromagnetic radiation spectrum.
Which of the following statements is NOT a valid reason for demagnetizing a part after
completing a magnetic particle test
,Demagnetizes the part
Subjecting a part to a magnetic field that is constantly reversing in polarity and gradually
diminishing in strength accomplishes which of the following
Permitting the solids to settle out of suspension
The concentration of the solid content in suspension of magnetic particles is measured by
The parts are painted
Magnetic particle inspection methods on ferromagnetic materials are recognized as superior to
liquid penetrant techniques when
is slightly magnetic
A paramagnetic material
Move the alternating current coil farther away from the part
Which of the following will reduce a magnetic field
Coercive force
When an external magnetizing force is removed, some of the magnetic domains remain
preferentially oriented. The additional force required to return them to their original random
orientation is commonly referred to as
At the inside surface of the cylinder
When is cylinder is magnetized by central conductor, the field is most intense
While the magnetizing current is applied
When is the magnetic field strongest in the object being inspected by the magnetic particle
method?
Direct current with reversing and step down control
Which demagnetization technique is most effective?
3000 A
When using a longitudinal magnetization technique to inspect a bar 152 mm (6in) bar and 51
mm (2in) in diameter with a 5 ton coil, what amperage value should be used?
3600 A
,To examine a part 127 mm (5in) long and 51 mm (2in) in diameter using a 5 turn coil and
headstock magnetic particle machine, what amperage should be used for longitudinal
magnetization?
1800 A
To examine a bar 381 mm (15in) long and 51 mm (2in) in diameter, what amperage should be
used on a stationary magnetic particle machine to create a direct circular magnetic field?
Of the 25 mm (1") bar will be approximately twice that of the 51 mm (2") bar
If the same amperage is passed through a 25 mm and 51 mm (1 inch and 2 inch) diameter bar
of the same length and material, the strength of the magnetic field at the surface
Both bars will be 0
If the same amperage is passed through a 25 mm (1 inch) diameter bar and a 51 mm (2 inch)
diameter bar of the same length and material, the strength of the magnetic field at the center
of
Circular field
When a magnetic field is induced in a part with prods spaced 152 mm (6") apart, the field is a
The skin effect of alternating current reduces the maximum depth at which discontinues can
be found
When circular magnetization is used to detect subsurface discontinuities, direct current is used
instead of alternating current because
Serge technique
An inspection technique in which an initial magnetization force is applied to a part and then
reduced to a lower continuous value is called the
The retentivity of a part
When deciding to inspect a part by the residual technique of applying the particles, what factor
affects the residual magnetic field strength of the part
Orientation and shape of the indication and the direction of the magnetic field
Factors that must be considered when interpreting an indication are the
6.0
, A 7 turn coil at 1000 A is used to inspect a round solid part 381 mm (15 inches) long and 64 mm
(2.5 inches) in diameter. The length to diameter ratio is
Longitudinal magnetization
When used as the last magnetizing technique, will best render a part suitable for a relatively
easy measurement of the external magnetic field using a field indicator?
Reinspect using alternating current
When using direct current an indication is detected. What is the next logical step to determine if
the indication results from a surface to subsurface condition?
Advantageous
With dry particles, particle mobility is
Cost of the equipment
The least important factor that should be considered when selecting a technique for
magnetization to detect subsurface discontinuities is
Laminations
Discontinuities that occur as a result of the rolling process
Laps
Discontinuities that occur as a result of the forging process
Is the highest while the current is being applied
The continuous technique provides the most sensitivity because flux density
Furring
Is not considered a surface coating that can affect the sensitivity of magnetic particle testing?
Enter the south pole and leave the north pole
The magnetic lines of flux in a permanent magnet
Parallel magnetization
Which of the following magnetization techniques is NOT recommended for magnetic particle
testing
Establish a longitudinal field and then proceed with demagnetization