QUIZ GEN Flashcards
Magnetic particles testing is most likely to find subsurface discontinuities in:
(a) Soft steels with high permeability
(b) Soft steels with low permeability
(c) Hardened steels with low permeability
(d) Hardened steels with high permeability
(a) Soft steels with high permeability
Which of the following is not an advantage of magnetic particles testing?
(a) Fast and simple to perform
(b) Can detect discontinuities filled with foreign material
(c) Most reliable for finding surface cracks in all types of material
(d) Works well through a thin coat of paint
(c) Most reliable for finding surface cracks in all types of material
Which of the following does not represent a limitation of magnetic particle testing?
(a) The type of materials which may be effectively tested
(b) The directionality of the magnetic field
(c) The need for demagnetization
(d) The ability to detect discontinuities filled with foreign material
(d) The ability to detect discontinuities filled with foreign material
- The most effective NDT method for locating surface cracks in ferromagnetic materials
is:
(a) Ultrasonic testing
(b) Radiographic testing
(c) Magnetic particle testing
(d) Liquid penetrant testing
(c) Magnetic particle testing
Which of the following may cause magnetic particle test indications?
(a) A joint between two ferromagnetic materials of different permeability
(b) A shrink fit joint in ferromagnetic materials
(c) A brazed joint in ferromagnetic materials
(d) All of the above
(a) A joint between two ferromagnetic materials of different permeability
(b) A shrink fit joint in ferromagnetic materials
(c) A brazed joint in ferromagnetic materials
(d) All of the above
discontinuity which is produced during solidification of the molten metal is called:
(a) Inherent
(b) Processing
(c) Service
(d) None of the above
(a) Inherent
Pipe would be classified as what type of discontinuity?
(a) Inherent
(b) Processing
(c) Service
(d) None of the above
(a) Inherent
- A lamination in steel plate would be classified as what type of discontinuity?
(a) Inherent
(b) Processing
(c) Service
(d) None of the above
(b) Processing
A seam would be classified as what type of discontinuity?
(a) Inherent
(b) Processing
(c) Service
(d) None of the above
(b) Processing
- An internal rupture caused by working steel at improper temperatures is called a:
(a) Lap
(b) Cold shut
(c) Forging burst
(d) Slag inclusion
(c) Forging burst
- Cracks which are caused by alternating stresses above a critical level are called:
(a) Stress corrosion cracks
(b) Cycling cracks
(c) Critical cracks
(d) Fatigue cracks
(d) Fatigue cracks
- Cracks which are caused by a combination of tensile stress and corrosion are called:
(a) Stress corrosion cracks
(b) Cycling cracks
(c) Critical cracks
(d) Fatigue cracks
(a) Stress corrosion cracks
- Which of the following are ferromagnetic materials?
(a) Aluminium, iron, copper
(b) Iron, copper, nickel
(c) Copper, aluminium, silver
(d) Iron, cobalt, nickel
(d) Iron, cobalt, nickel
- The reverse magnetising force necessary to remove a residual magnetic field from a
test piece after it has been magnetically saturated is called:
(a) Hysteresis
(b) Coercive force
(c) Demagnetising flux
(d) Reverse saturation
(b) Coercive force
- Magnetic lines of force enter and leave a magnet at:
(a) Saturation
(b) L/D ratios of greater than 4 to 1
(c) Flux concentration points
(d) Poles
(d) Poles
- The ease with which a magnetic field can be established in a test piece is called:
(a) Reluctance
(b) Retentivity
(c) Permeability
(d) Electromagnetism
(c) Permeability
- Opposition to establishment of a magnetic field is called:
(a) Reluctance
(b) Retentivity
(c) Permeability
(d) Electromagnetism
(a) Reluctance
- The ability of a material to remain magnetic after the magnetising force is removed is
called:
(a) Reluctance
(b) Retentivity
(c) Permeability
(d) Electromagnetism
(b) Retentivity
- A magnetic field which is contained completely within the test piece is called a:
(a) Confined field
(b) Longitudinal field
(c) Circular field
(d) Saturated field
(c) Circular field
- Which of the following produces a circular field?
(a) Coil
(b) Head shot
(c) Yoke
(d) All of the above
(b) Head shot
- A technique used to find transverse discontinuities at the ends of longitudinally
magnetised bars by the use of transient currents is called:
(a) A coil technique
(b) A fast break technique
(c) A yoke technique
(d) A head shot
(b) A fast break technique
- A leakage field is strongest when a discontinuity interrupts the magnetic flux lines at
an angle of:
(a) Zero degrees
(b) 45 degrees
(c) 90 degrees
(d) 180 degrees
(c) 90 degrees
- Magnetic flux density is zero at:
(a) The inside surface of a tube magnetised with a central conductor
(b) The outside surface of a tube magnetised with a central conductor
(c) The outside surface of a bar magnetised with a head shot
(d) The centre of a bar magnetised with a head shot
(d) The centre of a bar magnetised with a head shot
- The best method of inducing a circular field in a tube is by a:
(a) Central conductor
(b) Head shot
(c) Coil
(d) Prod technique
(a) Central conductor
- Magnetic flux density is highest at:
(a) The outside surface of a non-ferromagnetic tube magnetised with a central
conductor
(b) The inside surface of a non-ferromagnetic tube magnetised with a central
conductor
(c) The outside surface of a ferromagnetic tube magnetised with a central
conductor
(d) The inside surface of a ferromagnetic tube magnetised with a central conductor
(d) The inside surface of a ferromagnetic tube magnetised with a central conductor
- An important consideration when using a direct contact method is:
(a) Lifting power of the yoke
(b) Coil diameter
(c) Preventing arc burns
(d) Field strength adjacent to the coil inside diameter
(c) Preventing arc burns
- A prod method would be most sensitive to cracks:
(a) Parallel to a line connecting the prod contact points
(b) Tangential to a radius from each prod contact point
(c) Perpendicular to a line connecting the prod contact points
(d) Perpendicular to the long axis of the coil
(a) Parallel to a line connecting the prod contact points
- When using prods, arc burns may be caused by which of the following?
(a) Dirty contact tips
(b) Inadequate pressure
(c) Too large a magnetic current
(d) All of the above
(a) Dirty contact tips
(b) Inadequate pressure
(c) Too large a magnetic current
(d) All of the above
- The important difference between AC and DC current for magnetic particle testing
purposes is:
(a) The skin effect caused by DC adds mobility to the magnetic particles
(b) The resulting AC magnetic fields are more difficult to demagnetize
(c) The DC magnetic fields are more penetrating
(d) The AC magnetic fields are stronger
(c) The DC magnetic fields are more penetrating
- The ‘skin’ effect would be most noticeable in which of the following?
(a) A magnetic conductor carrying a DC current
(b) A nonmagnetic conductor carrying a DC current
(c) A magnetic conductor carrying a 50 Hz AC current
(d) A nonmagnetic conductor carrying a 50 Hz AC current
(d) A nonmagnetic conductor carrying a 50 Hz AC current
- The most common source of DC current for magnetic particle testing is:
(a) Motor generators
(b) Rectified AC
(c) Storage batteries
(d) None of the above
(b) Rectified AC
- Fields generated in ferromagnetic material with AC current are useful for locating:
(a) All discontinuities
(b) Surface cracks
(c) Subsurface discontinuities
(d) Internal porosity
(b) Surface cracks
- A common rule of thumb to use for current required in circular magnetisation:
(a) 1000 amps/25mm of diameter
(b) 1000 ampere turns/25mm of diameter
(c) 1000 amps/25mm of prod spacing
(d) None of the above
(b) 1000 ampere turns/25mm of diameter
- The formula, NI = 45000/(L/D), is used to calculate the proper magnetising current
for:
(a) Prod magnetization
(b) A head shot
(c) A central conductor
(d) Coil magnetisation
(d) Coil magnetisation
- The formula, NI = 45000/(L/D), gives proper magnetising current for a coil, regardless
of coil size as long as:
(a) The test piece is not larger than 1/10 the cross sectional area of the coil
(b) AC current only is used
(c) The test piece essentially fills the coil
(d) The test piece is held tightly against the coil
(a) The test piece is not larger than 1/10 the cross sectional area of the coil
- For direct contact magnetising methods, the magnetic field is oriented in what
direction relative to the current direction?
(a) Parallel
(b) At 45 degrees
(c) At 90 degrees
(d) At 180 degrees
(c) At 90 degrees