Test

Question 1

A material with a permeability of 1000:1 or greater is referred to as:

• Diamagnetic
• Paramagnetic
• Ferromagnetic
• Nonmagnetic

Answer 1

Ferromagnetic

Question 2

Magnetic lines of force (flux lines):

• Flow from North to South outside a magnet
• Follow the path of least resistance
• Distort and cross at a crack
• All of the above

Answer 2

All of the above

Question 3

Magnets are made from:

• Sharp and distinct
• Copper and aluminum
• Material with high permeability
• None of the above

Answer 3

Material with high permeability

Question 4

If a bar magnet was bent into a ring and fused together the magnetic field:

• Would be contained within the ring
• Would be stronger than the field in the bar magnet
• Would easily attract magnetic particles
• Would be cancelled out and, therefore, would not exist within the ring

Answer 4

Would be contained within the ring

Question 5

A material which, after being magnetized still has a strong magnetic field is said to have:

• Low permeability
• High retentively
• Both a and b
• High permeability

Answer 5

Both a and b

Question 6

A material which the atoms are easily aligned into magnetic domains would be said to have:

• Low reluctance
• High permeability
• Low retentively
• All the above

Answer 6

All the above

Question 7

When the point has been reached where a further increase in magnetizing force will not result in an increase in flux density:

• The material will become nonmagnetic
• The material is said to be saturated
• Magnetic hysteresis takes place
• The part is demagnetized

Answer 7

The material is said to be saturated

Question 8

Surface discontinuities are best detected by using:

• Rectified three phase AC
• Alternating current
• Direct current
• Half wave direct current

Answer 8

Alternating current

Question 9

When the flux field is parallel to a discontinuity the indication produced would be:

• Sharp and distinct
• Broad and fuzzy
• Weak or nonexistent
• Linear

Answer 9

Weak or nonexistent

Question 10

The magnetic field created in a part placed inside a current carrying coil is:

• A vector field
• A bi-polar field
• A longitudinal field

Answer 10

A longitudinal field

Question 11

Magnetizing a part in a current carrying coil will permit:

• Inspection of a long part (36” long or greater) in a single magnetizing operation
• Detection of circumferential type discontinuities
• Detection of both surface and subsurface discontinuities if HWDC is used
• Both b and c

Answer 11

Both b and c

Question 12

When it is desired to inspect the inside surface of a hollow tubular type part it is necessary to:

• Use a central conductor technique
• Use about half the amperage you would use if the part were solid
• Use alternating current
• None of the above

Answer 12

Use a central conductor technique

Question 13

In order to detect a subsurface discontinuity located parallel with the long axis of a ferromagnetic part, it would be necessary to:

• Magnetize the part by passing current through the part
• Create a circular magnetic field in the part
• Use a direct current, either HWDC or FWDC
• All the above

Answer 13

All the above would be necessary

Question 14

The strength of a magnetic field within a coil is dependent upon:

• The number of turns in the coil
• The current flowing through the coil
• The diameter of the coil
• All the above

Answer 14

All the above

Question 15

The magnetic field strength is greatest:

• While the current is flowing
• Immediately after the current is turned off
• When AC is used for magnetization
• At the center of a solid bar

Answer 15

While the current is flowing

Question 16

When using the dry continuous method the magnetizing current is:

-Usually HWDC
- Applied prior to application of only dry particles
- Allowed to continue flowing while particles are applied and excess particles are removed
- All of the above

Answer 16

Allowed to continue flowing while particles are applied and excess particles are removed

Question 17

When using the dry continuous method the magnetizing current is:

• Wet continuous
• Wet residual
• Dry continuous
• Dry residual

Answer 17

Wet residual

Question 18

An advantage of using fluorescent particles is:

• Greater visibility under normal lighting conditions
• Greater contrast between particle buildup and part surface
• Inspection time is less than if visible particles
• All the above

Answer 18

Greater contrast between particle buildup and part surface

Question 19

When using the residual method the magnetic particles:

• Should be applied just prior to application of the magnetizing force
• Should be the visible dry powder if AC is used as the magnetizing force
• Should be applied after the magnetizing operation has been completed
• None of the above

Answer 19

Should be applied after the magnetizing operation has been completed

Question 20

When subsurface discontinuities in a rough weld must be detected, the best method would be to:

• Wet continuous
• Dry continuous
• Wet residual
• Dry residual

Answer 20

Dry continuous

Question 21

When using the wet continuous method the duration of the magnetizing “shot” should be:

• About one-half to one minute
• About one-half to one second
• The duration of the shot is not important
• Varied depending on the type of material

Answer 21

About one-half to one second

Question 22

Stationary equipment may be used to accomplish:

• Circular magnetization
• Longitudinal magnetization
• Detection of fine surface discontinuities
• All the above

Answer 22

All the above

Question 23

When it is desired to detect discontinuities on the inside surface of a hollow tubular type part it would be necessary to:

• Use higher amperage than if the part were solid
• Use a wet fluorescent suspension
• Use the central conductor method
• Use a head shot

Answer 23

Use the central conductor method

Question 24

The formula N I = 45,000 AT/(L/D) is used:

• To calculate the amperage for a coil shot
• To calculate the amperage for ahead shot
• To calculate the amperage for a central conductor shot
• Both a and c

Answer 24

To calculate the amperage for a coil shot

Question 25

A discontinuity that is oriented perpendicular to the long axis of the part would best be detected with: - Direct contact method - Central conductor method - Longitudinal magnetization - None of the above would detect this type of discontinuity

Answer 25

Longitudinal magnetization

Question 26

When cables are wrapped around a part to fashion a coil: - It is recommended that a minimum of 5 wraps be used - It is recommended that a minimum of 3 wraps be used - It is recommended that AC be used for magnetization in order to detect all discontinuities - Both b and c

Answer 26

It is recommended that a minimum of 3 wraps be used

Question 27

Using the general rule of thumb, what amperage would be used to circularly magnetize a part that is 2.75” diameter by 13.5” long? • 1575 amps • 2225 amps • 2750 amps • 3000 amps

Answer 27

• 1575 amps

Question 28

The central conductor method: • Is an indirect method of magnetization • Can be used with AC current to detect discontinuities on the surface • Must be used in order to detect discontinuities on the inside surface of a tubular part • All of the above

Answer 28

All of the above

Question 29

What amperage would be required if the part is placed against the inside surface of a 12” diameter, 5 turn coil? NI=45,000 AT/ (L/D) • About 2100 amps • About 1653 amps • About 1830 amps • both b and c

Answer 29

About 1830 amps

Question 30

When using the contact prods care must be taken to assure good contact with the test surface in order to prevent: • Overheating (burning) of the surface • Excessive background indications • Arcing of the prods on the test surface • Both a and c

Answer 30

Both a and c

Question 31

When inspecting a long round part it may be more practical to attach contact clamps to each end of the part. This would permit the detection of discontinuities that are: • Not more than 1/2” deep • Oriented parallel with the long axis of the part • Oriented perpendicular with the long axis of the part • On the surface regardless of orientation

Answer 31

Oriented parallel with the long axis of the part

Question 32

When performing the settling test what is the purpose of passing the sample through the demagnetizer? • To increase the settling rate • To increase the permeability of the particles • To reduce clumping of the particles • All of the above

Answer 32

To reduce clumping of the particles

Question 33

When using the contact prods normal prod spacing would be: • 6-8” • 4-6” • 2-4” • Prod spacing would depend on the thickness of the part

Answer 33

6-8”

Question 34

An advantage of using an AC yoke is: • Portability • Uses standard 115 volt current • No problem with arcing • All of the above are advantages

Answer 34

All of the above are advantages

Question 35

What amperage would be used when inspecting a weld in a 1” thick plate using the contact prods and a 7” spacing? • 600-725 amps • 725- 875 amps • 700-825 amps • 700-875 amps

Answer 35

700-875 amps

Question 36

The “pie gage” is used to: • Verify adequacy and direction of magnetic field • Show orientation of discontinuities • Verify demagnetization • All of the above

Answer 36

Verify adequacy and direction of magnetic field

Question 37

Demagnetization is the process where by: • Residual magnetism is removed from the part • Residual magnetism is reduced to an acceptable level • A part is placed in a current carrying coil • The residual magnetic field is reversed in polarity

Answer 37

Residual magnetism is reduced to an acceptable level

Question 38

The most practical method of demagnetizing a part is to: • Pass the part through a current carrying coil • Use HWDC • Use AC • Both a and c

Answer 38

Both a and c

Question 39

Although it is possible to demagnetize using circular fields one problem is: • The coil has a magnetic field that extends only about 6-9 inches on either side of the coil • There are no external poles, therefore, residual magnetism is difficult to detect • A circular field is more difficult to cancel out than a longitudinal field • Much higher currents are required for circular demagnetization than for circular demagnetization

Answer 39

There are no external poles, therefore, residual magnetism is difficult to detect

Question 40

Some magnetic particle test units are equipped with a built-in demagnetizing circuit which accomplishes demagnetization through successive “shots”, each with a lower current value than the previous one. This referred to as: • Step-down demagnetization • HWDC demagnetization • Remnant field demagnetization • Nome of the above

Answer 40

Step-down demagnetization

Question 41

A part may not require demagnetization if: • More than .125” is to be machined from the surface • The part will be in the vicinity of a moving part such as a gear • The part has high permeability • None of the above

Answer 41

The part has high permeability

Question 42

The indication of a surface crack would probably appear: • Sharp and distinct • Broad and fuzzy • As a linear indication • Both a and c

Answer 42

Both a and c

Question 43

An indication: • Is a response that must be interpreted • Is an accumulation of magnetic particles • May or may not be cause for rejection • All of the above

Answer 43

All of the above

Question 44

An indication that is caused by a flux leakage due to the configuration of the part, such as a keyway, would be interpreted as: • A non-relevant indication • A discontinuity indication • A false indication • Cause for rejection

Answer 44

A non-relevant indication

Question 45

Indications caused when two parts, one or both having been magnetized, rub against each other are called: • Defect indications • False indications • Magnetic writing • Both b and c

Answer 45

Both b and c

Question 46

What does a field indicator using a Pie Gauge do:

Answer 46

Verify field direction