Magnetic Particle Inspection Quiz

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1

Since all matter is composed of atoms:

All parts can be tested with MPI if they are heated to their curie temperature

All materials can be tested with a MPI regardless of temperature

All materials are affected in some way by a magnetic field

None of the above 

2

Faraday’s Law of Magnetic Induction states that:

The flow of electrons can be used to generate a magnetic field

The magnetic forces of the material's electrons will be affected by an external magnetic field

Iron filings can be used to produce an indication of a flaw

Flux leakage is the byproduct of magnetic fields when testing aluminum alloys.

3

Magnetic particle inspection uses small ferromagnetic particles simmilar to:

Copper filing

Iron filings

Magnesium filings

Permanent Magnets 

4

A material with a narrower hysteresis loop has:

Higher reluctance

Lower coercivity

Higher retentivity

All of the above 

5

Magnetic particle inspection can be performed on parts made from which materials?

Iron, nickel, copper

Iron, nickel, cobalt

Nickel, cobalt, copper

Iron only 

6

Which of the following has a very weak and negative susceptibility to magnetic field?

Ferromagnetic materials

Diamagnetic materials

Paramagnetic materials

None of the above 

7

When a magnetic field cuts across a crack:

Electrons begin jumping back and forth across the crack

The crack begins to heat up

Magnetic poles form at the edges of the crack

All of the above 

8

A material with a narrower hysteresis loop has:

Higher residual magnetism

Higher permeability

Higher residual magnetism

Higher retentivity 

9   A volume of space where there is a change in magnetic energy is called:

A magnetic field

A magnetic dipole

A magnetic pole

A magnetic domain 

10

The magnetic field circling each loop of wire in a coil combines with the fields from the other loops to produce a concentrated field:

Which is maximized around the outside of the coil

Around each loop of the coil

Down the center of the coil

All of the above 

11

A longitudinal magnetic field has magnetic lines of force that run:

Parallel to the long axis of the part

90 degrees to the long axis of the part

Transverse to the long axis of the part

Opposite the waveform of the magnetic particle machine used 

12

The area where the exit poles are concentrated is called the magnet’s:

South pole

North pole

Dipole

Flux density 

13

A location where a magnetic field can be detected exiting or entering a material is called:

A magnetic pole

A magnetic field

A flux field

Polarity 

14

Magnetic lines of force:

Form closed loops from pole to pole

Will shift 180 degrees when a direct current is applied

Were discovered by Wilhelm Hurst

None of the above 

15

When testing parts with magnetic particles, it is best to magnetize the part:

In two directions at right angles to each other

With AC whenever possible

With DC whenever possible

With an amperage of at least 1000 amps 

16

An object that has a magnetic pole on one end and a second equal but opposite magnetic pole on the other is called a:

Dipole

Inductor

Capacitor

A ferromagnetic material 

17

When a ferromagnetic material is in a unmagnetized state, the domains are:

Aligned in a north and south direction

Aligned in a east and west direction

Randomly organized

Balanced to produce a gauss rating of 2 

18   Ferromagnetic materials are made up of small polarized regions known as:

Photons

Quarks

Electrons

Domains 

19

A circular magnetic field has lines of force that run:

Parallel to the long axis of the part

90 degrees to the long axis of the part

Circumferentially around the perimeter of the part

Opposite the waveform of the magnetic particle machine used 

20

A property of a material that describes the ease with which a magnetic flux is established in a component is called:

Retentivity

Residual magnetism

Coercive force

Permeability 

21

Which of the following has a large susceptibility to magnetic field?

Ferromagnetic materials

Diamagnetic materials

Paramagnetic materials

None of the above 

22

The best detection of defects occurs:

When the magnetic field is 10% beyond its saturation point

When the hysteresis loop shifts from positive to negative

When the lines of magnetic force are parallel to the longest dimension of the defect

When the lines of magnetic force are perpendicular to the longest dimension of the defect

23

Magnetic lines of force:

Almost never cross each other

Commonly cross each other

Will shift 90 degrees when a direct current is applied

Never cross each other 

24

When all the magnetic domains are aligned, the material is said to be:

Magnetically saturated

Partially magnetized

Magnetically stable

Unmagnetized 

25

Magnetic lines of force:

Have the same strength

Seek the path of least resistance

Decrease in density with increasing distance from the poles

All of the above 

26

The opposition that a ferromagnetic material shows to the establishment of a magnetic field is called:

Retentivity

Reluctance

Coercive force

Permeability 

27   A hysteresis loop shows the relationship between the:

Induced magnetic flux density and the magnetizing force

Induced magnetic flux density and the electron force

Electron flow and magnetic field strength

Flux density and number of coil turns 

28

A material with a wider hysteresis loop has:

Lower permeability

Higher retentivity

Higher coercivity

All of the above 

29

A material with a wider hysteresis loop has:

Lower reluctance

Lower residual magnetism

Higher residual magnetism

Higher premeability 

30

When performing a magnetic particle test with a coil, the part should be placed:

Along the outside edge the coil

Along the inside edge of the coil

Centered in the coil

None of the above 

31

A material with a narrower hysteresis loop has:

Higher permeability

Lower retentivity

Lower coercivity

All of the above 

32   The force required to remove the residual magnetism from the material is called the:

Inverse force

Reciprocal force

Coercive force

Residual force 

33

The magnetic flux density that remains in the material when the magnetizing force is zero is called:

Retentivity

Residual magnetism

Coercive force

Permeability 

34

The amount of reverse magnetic field which must be applied to a magnetic material to reduce the magnetic flux to zero is called:

Retentivity

Residual magnetism

Coercive force

Permeability 

35

A material with a wider hysteresis loop has:

Higher reluctance

Higher permeability

Lower retentivity

All of the above 

36   The number of magnetic lines of force cutting thorugh a plane of a given area at a right angle is known as the:

Magnetic flux leakage

Magnetic flux density

Magnetic ampere

None of the above 

37

When using the direct induction method:

The part must be placed in the center of the coil

Good electrical contact must be established between the test equipment and test component

The part may be tested in only one direction

It is not necessary to demagnetize the part 

38

When the magnetizing current is stopped, a ferromagnetic material will:

remain magnetically saturated

become demagnetized

retain a residual magnetic field withing the component

None of the above 

39

A yoke establishes a magnetic field:

That can be constant or pulsed

Between the north and south poles of the yoke

Equally in all directions around the poles

Both A and B 

40

A current carrying conductor induces a magnetic field:

By direct inductionBy direct induction

That is longitudinal

That is circular

By magnostriction 

41   Which type of current flows continuously in one direction at a constant voltage?

Direct current

Alternating current

Rectified alternating current

Half wave rectified alternating current 

42

The central conductor technique is sometimes used because it:

Allows large diameter circular parts to be completely inspected with one application of the magnetizing force

Produces a longitudinal field in circular parts

Establishes a magnetic field that extends from the ID to the OD of a circular part

None of the above 

43

Magnetic particle inspection has several advantages over liquid penetrant inspection which include:

Components with thin coatings can be inspected without removing the coating

Components can be inspected more rapidly

The technique is more portable

Both A and B 

44

The use of prods is sometimes restricted because:

They produce a relatively weak field

There is a potential for arcing that could damage parts

It is not possible to control the field orientation

None of the above 

45   Multidirectional inspection equipment:

Provides a more sensitive inspection

Provices a less sensitive inspection

Can be used without the need for QQIs

Reduces inspection time 

46

A material is considered demagnetized when:

Its residual magnetic field measures less than 5 gauss

It no longer produces an indication

It's no longer attracted to a magnet

Its residual magnetic field measures less than 3 gauss 

47

Materials can be demagnetized by:

Heating above thier curie temperature

Subjecting the component to a reversing and decreasing magnetic field

Both A and B

None of the above 

48

Components generally must be demagnetized because residual magnetism can:

Affect machining and welding processes

Interfere with near by electronic components

Increase wear by attracting abrasive particles

All of the above 

49

Dry magnetic particles:

Cannot be reused

Come in only one color

Are all of uniform size

None of the above 

  When using both a circular and longitudinal magnetic field, the

50 circular field is usually established first because:

It is more difficult to establish a circular field

It is easier to flip the domains of a circular field to a longitudinal field

It is easier to measure a longitudinal field

None of the above 

http://www.ndtcalc.com/index.php?page=quiz&method=mt&qs=50

50 Question MT quiz

1. The interpretation of magnetic particle indications may be aided by:

observing with a magnifying glass.

observing the indications as they are formed.

reproducing the indication residually.

all of the above.

2. Materials which are weakly attracted magnetically are classified as:

paramagnetic.

diamagnetic.

ferromagnetic.

nonmagnetic.

3. If an overall pattern (sometimes circular lines) appear on the test surfaces, how should the inspector reprocess the test piece?

Retest at a higher amperage.

Demagnetise.

Retest at lower amperage.

Both b and c.

4. Why are large soft contact areas such as lead or copper braid used for surfaces or headstocks?

to increase the area and reduce the possibility of burning the part.

because of their low melting points.

because they help heat metal, thus facilitation magnetic induction.

to increase the contact area and flux density.

5. Which of the following discontinuity may be found by magnetic particle inspection in a welded component made from rolled steel plate?

cold shut.

seam.

toe cracks.

lamellar tearing.

6. A rough forging that has received no further processing is MT tested. A very sharp indication is observed to run every direction, extending deeply into the part and perpendicular to the surface. What is the identity of the indication?

Forging burst.

Lap.

Flake.

Seam.

7. Residual magnetic fields may be used when:

Parts are irregular in shape.

Permeable.

Parts are highly stressed.

Evaluating continuous method indications.

8. A rough forging discontinuity has following characteristics: it occurs on the surface or internally; it is associated with processing at too low a temperature; it is often caused by excessive working; and it creates irregular cavities varying in size. How would it be identified or classified?

Burst.

Shrinkage.

Pipe.

Lamination.

9. Indications at the root of a notch caused by flux leakage resulting from the notch configuration are called:

discontinuities.

false indications.

relevant indications.

non-relevant indications.

10. To detect lengthwise defects on the inside diameter of hollow parts, you should:

Pass current through it.

Magnetize with a coil.

Pass current through a central conductor.

Increase the amperage used.

11. A limitation of low fill factor coil magnetisation techniques is that:

coil must be of minimum diameter in relation to part.

the effective field is generally limited on either side of the coil.

small diameter parts should be placed closed to the inner side of the coil.

all of the above.

12. The pattern of iron powder sprinkled on a paper placed over a bar magnet is called a:

field survey.

magnetometer.

magnetograph.

flux meter.

13. What wattage is most commonly used for mercury vapour bulbs for portable fluorescent magnetic particle inspection?

200 watts.

50 watts.

100 watts.

75 watts.

14. When using the wet method, why should a high velocity flow of wet method bath over surfaces following removal of the magnetizing current not be used?

It may wash away a fine or weakly held indication.

This is not a problem.

It may splash particles into eyes.

None of the above are correct.

15. Which of the following is an advantage of the dry method over the wet method?

it is more sensitive to fine surface cracks.

it is more capable of providing full surface coverage on irregularly shaped parts.

it is easier to use on warm parts.

it is faster than the wet method when testing a number of small parts.

16. Since the magnetic lines of force within a bar magnet run the length of the bar, it is said to be:

randomly magnetised.

permanently magnetised.

circularly magnetised.

longitudinally magnetised.

17. Why is it preferable to disassembly parts before magnetic particle inspection?

Disassembly makes all surface areas visible.

Interfaces will create leakage fields which may confuse the inspection.

It is usually easier to handle the disassembled parts.

all of the above.

18. When adding concentrate to any wet magnetic particle suspension liquid it is common practice:

to add dry powder directly to the suspension liquid.

to make a small, concentrated mixture of the powder in liquid.

both of the above.

neither of the above.

19. In longitudinal magnetization the proper term for calculating magnetizating force is:

Amperes.

Amperes-turns.

Watts.

Ohms.

20. An interruption in the normal physical structure or configuration of a part which produces an MT indication is called:

a discontinuity.

a defect.

an indication.

a deformation.

21. A coil around the part produces:

A circular field.

A Longitudinal field.

Either a or b depending on the type of current applied.

An intermittent field.

22. A prime consideration when selecting a powder to be used as a magnetic particle medium is to select a powder that:

provides a high contrast to the surface being tested.

provides a low contrast to the surface being tested.

will adhere to the surface being tested.

requires a high demagnetisation current to remove it.

23. The term used to refer to the total opposition to flow of current represented by the combined effect of resistance, inductance and capacitance of a circuit is:

inductive reactance.

impedance.

reluctance.

decay.

24. Half wave rectified AC (HWDC) is the best current to use for detection of:

surface defects.

subsurface defects.

surface and subsurface defects.

none of the above.

25. When testing for fine surface cracks, the preferred MT method should be:

dry AC.

dry DC.

wet AC.

wet DC.

26. Retentivity refers to a materials ability to retain a certain amount:

of permeability after magnetisation.

of coercive force.

of residual magnetism.

none of the above.

27. Discontinuities in plate, sheet, or strip caused by pipe, inclusions, or blowholes in the original ingot which after rolling are usually flat and parallel to the outside surface are called:

seams.

laminations.

cracks.

laps.

28. The ability of matter to attract other matter to itself is a phenomenon associated with:

field strength.

magnetism.

coercive force.

pole strength.

29. A specimen may be demagnetized by which of the following methods?

Heat treatment above curie temperature.

AC coil.

Reversing DC fields with reducing current.

All of the above.

30. The deeper a sub-surface discontinuity lies below the surface:-

the more diffuse the magnetic particle indication.

the more serious it is as a potential source of fatigue failure.

the more distinct the magnetic particle indication.

the easier it is to detect by magnetic particle inspection.

31. If a copper conductor is placed through a ferrous cylinder and a current is passed through the conductor, then the magnetic field (flux density) in the cylinder will be:

the same intensity and pattern as in the conductor.

greater than in the conductor.

less than in the conductor.

the same regardless or its proximity to the cylinder wall.

32. The strongest magnetic field in a coil is at the:

Outside edge.

Inside edge.

Centre.

End.

33. If a current of the same amperage is passed through two conductors of the same dimensions, one of which is magnetic and one of which is non-magnetic, the magnetic field surrounding the conductors will:

be stronger for the magnetic conductor.

be stronger for the non-magnetic conductor.

vary with the permeability.

be the same for both conductors.

34. Which of the following materials would be UNSUITABLE for magnetic particle inspection?

low carbon steel (miled steel).

high carbon steel )tool steel).

medium carbon steel.

austenitic stainless steel.

35. What type of magnetisation used the formula: Ampere-turns=45,000(L/D)?

Circular.

Longitudinal.

Parallel.

Vectored.

36. The magnetic particle test technique in which the indicating medium is applied after ceasing application of the magnetising force is called the:-

induced current flow method.

continuous magnetisation method.

residual magnetisation method.

sustained magnetisation method.

37. In order to detect defects in different directions in a material by magnetic particle inspection, it is best to use:

two or more fields in different directions.

only one field.

other probe locations.

a high frequency field.

38. What equipment is used to determine if a part has been demagnetized?

A magnet on the part.

A field meter.

A survey meter.

Careful observation for clinging magnetic particles.

39. The parts are blanks cut from rolled iron bar stock. They have been rough machined. Inspection by the continuous method, using a circular short, reveals well-defined but broken lines running parallel with the axis on some of the pieces and non indication on others. The broken lines range in length from 6mm to 25mm. These indications are indicative of:

shrinkage.

machining tears.

surface checking.

nonmetallic inclusions.

40. Comparing parts that have been circularly magnetised and those which have been longitudinally magnetised, which retains the most objectionable residual field if not demagnetised?

Longitudinal.

Circular.

Vectored.

Remnant.

41. The length of a part being magnetised by passing an electric current from one end to the other:

affects the permeability of the part.

changes the strength of the magnetic field.

does not affect the strength of the magnetic field .

causes the magnetic field to vary.

42. Cold working indications will not reappear if the part is:

demagnetised then retested.

retested after stress relieving.

rested in the opposite direction.

remagnetised at a higher amperage.

43. The most effective MT method for inspection of a large casting is using:

multidirectional magnetisation.

a central conductor.

yoke inspection in two directions.

direct magnetisation.

44. Which type of black light source is most suitable for inspection when fluorescent magnetic particle inspection is to be carried out?

incandescent black light.

black light fluorescent tubes.

mercury arc lamp with a flood globe.

mercury arc lamp with a spot globe.

45. A break in the magnetic uniformity of a part that is called a magnetic discontinuity is related to a sudden change in:

inductance.

resistivity.

capacitance.

permeability.

46. Where particles are attracted to a site on the surface of a party by a magnetic leakage field which is due to a condition such as a crack, lap, or other condition not acceptable to the applicable standards for the part, then we have:

discontinuity.

defect.

non-relevant indication.

all of the above.

47. What is the minimum temperature a steel containing 0.8%C has to be heated to before quench cracking can occur?

910o C.

640o C.

725o C.

770o C.

48. Which of the following casting defects is caused by non-uniform cooling resulting in stresses which rupture the surface of the metal?

Shrinkage.

Hot tears.

Porosity.

Dross.

49. An electromagnetic yoke produces:

A longitudinal filed.

A circular field.

Alternating fields.

A swinging field.

50. Internal splines and holes drilled parallel to and near test surfaces will cause:

broad, fuzzy indications directly aligned with the parts internal contours.

sharp, well-defined indications directly aligned with the parts internal contours.

no indications.

both a and b above.