CWB LEVEL 2 QUESTIONS &
ANSWERS(RATED A+)
What are the 5 main categories for LP indications - ANSWER1. Continuous Line
2. Intermittent Line
3. Rounded
4. Small Dots
5. Diffused or weak
surface tension - ANSWERproperty of a liquid that tends to reduce the area of the
surface
contact angle - ANSWERthe angle that the base of a drop of water makes with the
surface it is on
If a Liquid has good wetting it has a _________ Contact Angle - ANSWERSmall
Contact Angle
capillary action - ANSWERtendency of water to rise in a thin tube
How are LP Procedures/Techniques Qualified - ANSWERComparator Block
False Indications - ANSWERIndications not associated with a discontinuity of any kind
Nonrelevent Indications - ANSWERIndications cause by features or design of material
What Standard are CGSB inspectors certified to? - ANSWERCAN/CGSB 48.9712
MP can not be used on what types of materials? - ANSWER1. Non Ferrous
2. Austenitic Stainless
3. Copper
4. Aluminum
flux leakage field - ANSWERa path created between 2 new polls as a result of an
indication
Lines of force must run ________ to the crack, for the crack to appear. -
ANSWERperpendicular
induced magnetism - ANSWERthe influence of a external magnetic field on a piece of
iron, which makes the iron a temporary magnet
Flux density - ANSWERA measure of the density of the field lines around a magnet
, Permeability - ANSWERthe ability for a material to hold its magnetism.
Magnetic saturation - ANSWERWhen the flux reaches a maximum and the material can
no longer be further magnetized.
Magnetic Retentivity - ANSWERthe ability of a material to stay magnetized
How do inspectors remove a materials retained flux? - ANSWERapply field in opposite
direction
Coercive Force - ANSWERthe strength of the reverse field necessary to bring the
induced flux to zero.
what range should the applied filed be applied to avoid saturation of a material? -
ANSWER30 to 70%
electric current produces what kind of magnetic field? - ANSWERcircular
during MT inspection an AC will magnetize the ______ of the part. - ANSWERsurface
(skin effect)
Direct current applied during MT Inspection has the ability to penetrate how far into the
material? - ANSWER2- 3 mm
During MT inspection which methods is more sensitive?
a. wet
b. dry - ANSWERa. wet
variations in permeability can arise from? - ANSWER1. composition
2. micro structure
3. hardness
4. heat treatment
5. work hardening
how may a part be demagnetized? - ANSWERby reversing and reducing the magnetic
field
what type of detector is used to detect local leakage fields? - ANSWERhall detector
eddy currents - ANSWERinduced currents in the metal parts of ac machines
Reactance - ANSWERwhen a flaw is present in a piece of metal it wil disrupt the eddy
current.
Eddy current can inspect up to ____ mm in to material - ANSWER6 mm
ANSWERS(RATED A+)
What are the 5 main categories for LP indications - ANSWER1. Continuous Line
2. Intermittent Line
3. Rounded
4. Small Dots
5. Diffused or weak
surface tension - ANSWERproperty of a liquid that tends to reduce the area of the
surface
contact angle - ANSWERthe angle that the base of a drop of water makes with the
surface it is on
If a Liquid has good wetting it has a _________ Contact Angle - ANSWERSmall
Contact Angle
capillary action - ANSWERtendency of water to rise in a thin tube
How are LP Procedures/Techniques Qualified - ANSWERComparator Block
False Indications - ANSWERIndications not associated with a discontinuity of any kind
Nonrelevent Indications - ANSWERIndications cause by features or design of material
What Standard are CGSB inspectors certified to? - ANSWERCAN/CGSB 48.9712
MP can not be used on what types of materials? - ANSWER1. Non Ferrous
2. Austenitic Stainless
3. Copper
4. Aluminum
flux leakage field - ANSWERa path created between 2 new polls as a result of an
indication
Lines of force must run ________ to the crack, for the crack to appear. -
ANSWERperpendicular
induced magnetism - ANSWERthe influence of a external magnetic field on a piece of
iron, which makes the iron a temporary magnet
Flux density - ANSWERA measure of the density of the field lines around a magnet
, Permeability - ANSWERthe ability for a material to hold its magnetism.
Magnetic saturation - ANSWERWhen the flux reaches a maximum and the material can
no longer be further magnetized.
Magnetic Retentivity - ANSWERthe ability of a material to stay magnetized
How do inspectors remove a materials retained flux? - ANSWERapply field in opposite
direction
Coercive Force - ANSWERthe strength of the reverse field necessary to bring the
induced flux to zero.
what range should the applied filed be applied to avoid saturation of a material? -
ANSWER30 to 70%
electric current produces what kind of magnetic field? - ANSWERcircular
during MT inspection an AC will magnetize the ______ of the part. - ANSWERsurface
(skin effect)
Direct current applied during MT Inspection has the ability to penetrate how far into the
material? - ANSWER2- 3 mm
During MT inspection which methods is more sensitive?
a. wet
b. dry - ANSWERa. wet
variations in permeability can arise from? - ANSWER1. composition
2. micro structure
3. hardness
4. heat treatment
5. work hardening
how may a part be demagnetized? - ANSWERby reversing and reducing the magnetic
field
what type of detector is used to detect local leakage fields? - ANSWERhall detector
eddy currents - ANSWERinduced currents in the metal parts of ac machines
Reactance - ANSWERwhen a flaw is present in a piece of metal it wil disrupt the eddy
current.
Eddy current can inspect up to ____ mm in to material - ANSWER6 mm
