MT LEV-II 59 Cards Harold Bennett 2025

Question 1

For which of the following would the wet fluorescent technique be preferred over the dry technique?

Answer 1

When increased speed and sensitivity are desired.

Question 2

The magnetic domains in a permanent magnet are aligned in:

Answer 2

Fixed positions, predominantly in one direction.

Question 3

Gas, hot tears, cold shuts, shrinkage cracks and sand inclusions are examples of defects resulting from which of the following processes?

Answer 3

Casting.

Question 4

Which of the following statements is a valid reason for demagnetizing a part after completing a magnetic particle test?

Answer 4

If the part is to be radiographed after magnetic particle inspection, residual magnetism may interfere with the electromagnetic radiation spectrum.

Question 5

Subjecting a part to a magnetic field that is constantly reversing in polarity and gradually diminishing in strength accomplishes which of the following?

Answer 5

Demagnetizes the part.

Question 6

The concentration of the solid content of a suspension of magnetic particles is measured by:

Answer 6

Permitting the solids to settle out of suspension.

Question 7

An important factor that must be considered when selecting a method of magnetization is the:

Answer 7

Alloy, shape, and condition of the part.

Question 8

When a magnetic material reaches its Curie temperature, the material becomes:

Answer 8

Paramagnetic.

Question 9

Magnetic particle inspection methods on ferromagnetic materials are recognized as superior to liquid penetrant techniques when:

Answer 9

The parts are painted.

Question 10

A paramagnetic material:

Answer 10

Is slightly magnetic.

Question 11

Which of the following will reduce a magnetic field?

Answer 11

Move the alternating current coil further away from the part.

Question 12

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:

Answer 12

Coercive force.

Question 13

When a cylinder is magnetized by a central conductor, the field is most intense:

Answer 13

At the inside surface of the cylinder.

Question 14

When is the magnetic field strongest in an object being inspected by the magnetic particle method?

Answer 14

While the magnetizing current is applied.

Question 15

Which of the demagnetization methods listed below is most effective?

Answer 15

Direct current with reversing and step-down control.

Question 16

When using the longitudinal magnetization method to inspect a bar 152 mm (6 in.) long and 51 mm (2 in.) in diameter with a 5-turn coil, which of the following amperage values should be used?

Answer 16

3000A.

Question 17

To examine a part 127 mm (5 in.) long and 51 mm (2 in.) in diameter using a 5-turn coil and head stock magnetic particle machine, what amperage should be used for longitudinal magnetization?

Answer 17

3600A.

Question 18

To examine a bar 381 mm (15 in.) long and 51 mm (2 in.) in diameter using a 7-turn coil and head-stock magnetic particle machine, what amperage should be used for circular magnetization?

Answer 18

1800A.

Question 19

If the same amperage is passed through a 25 mm and 51 mm (1 in. and a 2 in.) diameter bar of the same length and material, the strength of the magnetic field at the surface:

Answer 19

Of the 25 mm (1 in.) bar will be approximately twice that of the 51 mm (2 in.) bar.

Question 20

If the same amperage is passed through a 25 mm (1 in.) diameter bar and a 51 mm (2 in.) diameter bar of the same length and material, the strength of the magnetic field at the center of:

Answer 20

Both bars will be 0.

Question 21

When a magnetic field is induced in a part with prods spaced 152 mm (6 in.) apart, the field is a:

Answer 21

Circular field.

Question 22

When circular magnetization is used to detect subsurface discontinuities, direct current is used instead of alternating current because:

Answer 22

The skin effect of alternating current reduces the maximum depth at which discontinuities can be found.

Question 23

An inspection method in which an initial magnetizing force is applied to a part and then reduced to a lower continuous value is called:

Answer 23

The surge method.

Question 24

When deciding to inspect a part by the residual method of applying the particles, what factor affects the residual magnetic field strength of the part?

Answer 24

The retentivity of the part.

Question 25

Factors that must be considered when interpreting an indication are:

Answer 25

The orientation and shape of the indication and the direction of the magnetic field.

Question 26

A 7-turn coil at 1000 A is used to inspect a round solid part 381 mm (15 in.) long and 64 mm (2.5 in.) in diameter. The length-to-diameter ratio is:

Answer 26

6.0.

Question 27

Which of the following, when used as the last magnetizing method, will best render a part suitable for relatively easy measurement of the external magnetic field using a field indicator?

Answer 27

Longitudinal magnetization.

Question 28

When using direct current an indication is detected. What is the next logical step to determine if the indication results from a surface or subsurface condition?

Answer 28

Reinspect using alternating current.

Question 29

Which of the statements below is most appropriate concerning materials I and II represented by the hysteresis curves shown in Figure 1?

Answer 29

Material II could be used for dry powder magnetic particles.

Question 30

Considering the curves shown in Figure 1, material II in comparison to material I indicates that the material:

Answer 30

Has a high permeability.

Question 31

Point B on the hysteresis curve for material I shown in Figure 1:

Answer 31

Is the material’s magnetic saturation point.

Question 32

Which point on the hysteresis curve shown in Figure 1 represents the residual field value?

Answer 32

C.

Question 33

When withdrawing a part from the field around a coil and without changing the direction of current, which of the following has the least effect on demagnetizing the part?

Answer 33

Direct current.

Question 34

The least important factor below that should not be considered when selecting a method of magnetization to detect subsurface discontinuities is:

Answer 34

Cost of the equipment.

Question 35

Which of the following discontinuities occur as a result of the rolling process?

Answer 35

Laminations.

Question 36

Which of the following discontinuities occur as a result of the forging process?

Answer 36

Laps.

Question 37

If an indication is formed when using the residual method as well as the continuous method, it is most likely:

Answer 37

A relevant indication.

Question 38

Plated parts can be reliably tested for fine surface cracks using the magnetic particle method if the plating is less than:

Answer 38

0.127 mm (0.005 in.) thick.

Question 39

The magnetic lines of flux in a permanent magnet:

Answer 39

Enter the south pole and leave through the north pole.

Question 40

Which of the following magnetization techniques is not recommended for magnetic particle testing?

Answer 40

Parallel magnetization.

Question 41

When attempting to demagnetize a part containing a circular residual field:

Answer 41

Establish a longitudinal field and then proceed with demagnetization.

Question 42

Small parts requiring demagnetization should be:

Answer 42

Processed through a demagnetization cycle one at a time.

Question 43

The best shape for magnetic particles used in the dry powder method is:

Answer 43

A mixture of elongated and globular.

Question 44

The best method for testing ball bearings is:

Answer 44

Induced current shots along X, Y, and Z axis, rotating 360 degrees during each shot.

Question 45

When a magnetized ferromagnetic object is exposed to a subsequent heating operation above the Curie point:

Answer 45

The magnetic domains become random.

Question 46

A discontinuity caused by a welding operation is:

Answer 46

Lamellar tearing.

Question 47

The most effective current to be used with dry magnetic particle is:

Answer 47

Half-wave rectified alternating current.

Question 48

The following properties should be considered in choosing a vehicle for the wet method, except:

Answer 48

Capillarity.

Question 49

The amount of light reflected by one surface compared to that reflected by another adjacent surface is:

Answer 49

Brightness contrast.

Question 50

Given a certain continuous magnetization current in a material, which type of current would give the deepest penetration?

Answer 50

Half-wave direct current.

Question 51

Given a certain continuous magnetization current in a material, which type of current would give the shallowest penetration?

Answer 51

Alternating current.

Question 52

Which type of radiation can most damage human tissue?

Answer 52

UV-B.

Question 53

Compared with magnetic particle testing, liquid penetrant testing is not reliable after paint removal from weld because:

Answer 53

Partial smearing of weld surface metal across the discontinuity opening can occur.

Question 54

Prod spacing less than 76.2 mm (3 in.) is usually not practical because:

Answer 54

Particles tend to bend around the prod making interpretation difficult.

Question 55

One of the most important facts that must be remembered while establishing magnetic particle procedure:

Answer 55

In most cases the continuous method is more sensitive than is the residual method.

Question 56

Which one of the following magnetic particle testing techniques is logically acceptable for testing a large flat area?

Answer 56

Prod.

Question 57

Permeability of a material can be numerically written as:

Answer 57

BM.

Question 58

One disadvantage for using undyed wet magnetic particles is:

Answer 58

The lack of contrasting color makes them difficult to see.

Question 59

One of the most desirable characteristics of the media for magnetic particle testing is:

Answer 59

The highest possible permeability and lowest retentivity.