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
- For direct contact magnetising methods, current should be flowing in what direction
relative to expected discontinuities?
(a) Parallel
(b) At 45 degrees
(c) At 90 degrees
(d) At 180 degrees
(a) Parallel
- What is the magnetic field strength at the surface of a 100 mm diameter bar as
compared to that at the surface of a 50 mm diameter bar, each carrying 1000 amps of
current?
(a) Twice
(b) One half
(c) One quarter
(d) Four times
(b) One half
- What is the magnetic field strength at the surface of a 25mm diameter bar as compared
to that at the surface of a 50mm diameter bar, each carrying 1000 amps of current?
(a) Twice
(b) One half
(c) One quarter
(d) Four times
(a) Twice
- The magnetic field outside a conductor decreases:
(a) Exponentially
(b) In a linear manner
(c) Inversely with distance
(d) Inversely with the square of distance
(b) In a linear manner
- How is the magnetic field strength at the surface of a magnetic conductor having
permeability, μ, related to the magnetic field strength, F, at the surface of a
nonmagnetic conductor carrying the same current?
(a) F × μ
(b) Same
(c) F/μ
(d) Not related
(b) Same
- Compared to the magnetic field strength at the outer surface, the magnetic field
strength, at the centre of a hollow, nonmagnetic conductor carrying DC current is:
(a) I/D
(b) The same
(c) Zero
(d) Need more information to determine
(c) Zero
- How is the magnetic field strength, F, just outside a magnetic conductor having
permeability, μ, related to that just outside a nonmagnetic conductor of the same size,
carrying the same current?
(a) F × μ
(b) Same
(c) (F)/μ
(d) Not related
(b) Same
- Which of the following describes the shape of particles used for dry magnetic particle
testing?
(a) Spherical
(b) Angular
(c) Elongated
(d) Mixture of elongated and globular
(d) Mixture of elongated and globular
- Which of the following particles would be most sensitive?
(a) Wet
(b) Dry
(c) Depends on the test piece permeability
(d) None of the above
(b) Dry
- Which of the following colours is readily available for magnetic particle test powder?
(a) Red
(b) Gray
(c) Black
(d) All of the above
(a) Red
(b) Gray
(c) Black
(d) All of the above
- A magnetic particle testing technique in which the test piece is magnetised and
magnetic particles applied after the magnetising force has been removed is called the:
(a) Magnetic method
(b) Continuous method
(c) Residual method
(d) Discontinuous method
(c) Residual method
- Which of the following characteristics would be most important in a test piece which
is to be tested using the residual method?
(a) High rententivity
(b) High permeability
(c) Low reluctance
(d) Low permeability
(a) High rententivity
- The wet method is superior to dry particles for detecting:
(a) Subsurface discontinuities
(b) Fine surface cracks
(c) Open surface cracks
(d) None of the above
(b) Fine surface cracks
- Selection of magnetic particle colour is based on:
(a) Optimum performance of magnetic particle/developer
(b) Colour of inspection light available
(c) Obtaining maximum contrast with the test piece background
(d) Optimum colour response of the human eye
(c) Obtaining maximum contrast with the test piece background
- The residual method is applicable to:
(a) Surface discontinuities only
(b) Subsurface discontinuities only
(c) Either surface or subsurface discontinuities
(d) All but tight surface cracks
(a) Surface discontinuities only
- Highest sensitivity to fine surface cracks would be obtained by which of the following
techniques?
(a) Residual field, wet method
(b) Residual field, dry method
(c) Continuous field, wet method
(d) Continuous field, dry method
(c) Continuous field, wet method
- A residual field is always less than a continuous field because?
(a) The magnetic field, as shown by a hysteresis curve, is zero when there is no
magnetising force
(b) The magnetic field, as shown by a hysteresis curve, is less when there is no
magnetising force
(c) The magnetic field, as shown by a hysteresis curve, is greater when there is no
magnetising force
(d) None of the above
(b) The magnetic field, as shown by a hysteresis curve, is less when there is no
magnetising force
- Where possible, circular magnetisation is preferable to longitudinal magnetization
because:
(a) Less current is required
(b) Stronger fields are obtained
(c) Fewer confusing secondary poles are produced
(d) None of the above is true
(d) None of the above is true
- Which of the following is a disadvantage of the dry method?
(a) Ease of application with portable equipment
(b) Superior sensitivity for fine surface cracks
(c) Good particle mobility with AC and HWDC
(d) Good sensitivity for subsurface discontinuities
(b) Superior sensitivity for fine surface cracks
- Which of the following is an advantage of the dry method
(a) Good sensitivity for subsurface discontinuities
(b) Faster than wet method for quantities of small test pieces
(c) Easily applied in an automated system
(d) Easy coverage of surfaces of irregularly shaped test pieces
(a) Good sensitivity for subsurface discontinuities
- Loss of fine particle sizes due to re-use of dry particles would probably lead to:
(a) Loss of sensitivity to larger discontinuities
(b) Loss of sensitivity to finer discontinuities
(c) Unpredictable results
(d) Slower inspection speeds
(b) Loss of sensitivity to finer discontinuities
- Which of the following is a disadvantage of the wet method?
(a) It is the most sensitive method for detection of very fine surface cracks
(b) Rapid testing of large quantities of small test pieces
(c) Readily adaptable to mechanised equipment
(d) Excellent detection of completely subsurface discontinuities
(d) Excellent detection of completely subsurface discontinuities
- Which of the following is an advantage of the wet method?
(a) Excellent detection of completely subsurface discontinuities
(b) Ease of bath recovery and re-use
(c) Low flash point ensures freedom from fire hazards
(d) Relatively clean and easy to work with
(b) Ease of bath recovery and re-use
- The primary reason for using water rather than oil as a suspension medium for wet
method baths is that:
(a) Water is more chemically inert than oil
(b) Bath flammability hazards are eliminated
(c) Water has the capability to dissolve the needed rust inhibitors
(d) Water baths may be used at lower temperatures than oil baths
(b) Bath flammability hazards are eliminated
- A disadvantage of fluorescent magnetic particles is:
(a) Darkened area and black light are required
(b) Abnormally high sensitivity
(c) Only dry particles are available
(d) Only wet concentrate is available
(a) Darkened area and black light are required
- A common physiological effect of black light inspection on the inspector is:
(a) Burned retinas of the eyes
(b) Rejected cornea syndrome
(c) Eye fatigue
(d) Retarded iris control
(c) Eye fatigue
- A common physiological effect of black light inspection on the inspector is:
(a) Burned retinas of the eyes
(b) Rejected cornea syndrome
(c) Eyeball fluorescence
(d) Retarded iris control
(c) Eyeball fluorescence
- Which of the following represents ultraviolet light of wavelengths which are
potentially injurious (1 Å = 10-10m)
(a) 2000 to 3200 Å
(b) 3200 to 4000 Å
(c) 4000 to 4600 Å
(d) 4600 to 5200 Å
(a) 2000 to 3200 Å
- Dyes which receive light at one wavelength and re-emit light of another wavelength
are called:
(a) L.E.Ds
(b) Phosphorescent
(c) Luminescent
(d) Fluorescent
(d) Fluorescent
- Most fluorescent dyes used for magnetic particle testing fluoresce what colour?
(a) Blue green
(b) Yellow green
(c) Blue black
(d) Red orange
(b) Yellow green
- The best available source of black light for inspection is:
(a) The mercury vapour lamp
(b) The fluorescent tube
(c) The incandescent bulb
(d) Sunlight
(a) The mercury vapour lamp
- Which of the following would be likely to cause variations in the output of an
inspection black light?
(a) Voltage fluctuations
(b) Aged bulb
(c) Dirty filter
(d) All of the above
(a) Voltage fluctuations
(b) Aged bulb
(c) Dirty filter
(d) All of the above
- The temperature above which steels become nonmagnetic is called the:
(a) Zero retentivity
(b) Curie point
(c) Demagnetisation temperature
(d) Random polar point
(b) Curie point
- The temperature above which most soft steels become nonmagnetic is about:
(a) 440ºC (770oF)
(b) 523ºC (975ºF)
(c) 626ºC (1160ºF)
(d) 754ºC (1390ºF)
(d) 754ºC (1390ºF)
- The most common method of demagnetising small test pieces is:
(a) Heat treatment
(b) Shot peening
(c) Passing through an AC coil
(d) Direct contact with AC current
(c) Passing through an AC coil
- Demagnetisation with reversing DC is more effective than AC because:
(a) DC is more penetrating
(b) Demagnetisation is assisted by the skin effect
(c) DC is more direct
(d) Not true - AC is more effective
(a) DC is more penetrating
- The type of discontinuity which magnetic particle testing most effectively locates is:
(a) Slag inclusions
(b) Magnetic writing
(c) Porosity
(d) Surface cracks
(d) Surface cracks
- An indication which is formed when two pieces of magnetised steel come in contact
with each other is called:
(a) A metallurgical discontinuity
(b) Magnetic writing
(c) Magnetic transfer
(d) A ferromagnetic notch
(b) Magnetic writing
- Magnetic particle test indications which are due to cold work can best be removed by:
(a) Demagnetisation
(b) Using a lower current
(c) Re-crystallisation
(d) Heat treating
(d) Heat treating
- Which of the following might cause non-relevant indications?
(a) Over magnetisation
(b) Indications at the edges of a braze joint
(c) A joint between hard and soft steels
(d) All of the above
(a) Over magnetisation
(b) Indications at the edges of a braze joint
(c) A joint between hard and soft steels
(d) All of the above
- An inspection for surface and subsurface discontinuities in ferromagnetic welds would
best be accomplished by which of the following techniques?
(a) Prods
(b) AC yoke
(c) Half wave DC yoke
(d) None of the above
(a) Prods
- A continuous linear indication along the centre of a fillet weld would most likely be a:
(a) Crater crack
(b) Overlap
(c) Root indication
(d) None of the above
(c) Root indication
- Wet magnetic particle bath strength is checked by which of the following?
(a) Specific gravity
(b) Optical density
(c) Settling test
(d) None of the above
(c) Settling test
- Which of the following describes the best technique for applying dry magnetic
particles to a test piece?
(a) Dip the test piece in a tank of dry particles while current is flowing
(b) Apply with an electrostatic spray gun at approximately 30 PSIG
(c) Gently pour the powder onto the test piece
(d) Shake or dust the powder onto the test piece with minimum velocity
(d) Shake or dust the powder onto the test piece with minimum velocity
- An advantage of AC equipment over DC is:
(a) AC is more penetrating
(b) AC is less hazardous
(c) AC makes the magnetic particles more mobile on the test surface
(d) AC equipment is heavier than DC
(c) AC makes the magnetic particles more mobile on the test surface
- When the orientation of likely discontinuities is unknown, what is the minimum
number of magnetising operations required to perform an adequate test?
(a) 1
(b) 2
(c) 3
(d) None of the above
(b) 2
- Maximum practical prod spacing is about:
(a) 100 mm
(b) 200 mm
(c) 300 mm
(d) 450 mm
b) 200 mm
- Magnetic lines of flux which are parallel to a discontinuity produce:
(a) Strong indications
(b) Weak indications
(c) No indications
(d) Fuzzy indications
(c) No indications
- The area of maximum induced field strength using a yoke is:
(a) At the north pole of the yoke
(b) At the south pole of the yoke
(c) The area directly between the poles
(d) On the outside of the pole pieces
(c) The area directly between the poles
- A minimum of external poles are produced by what type of magnetisation?
(a) Continuous
(b) Residual
(c) Circular
(d) Longitudinal
(c) Circular
- A split coil would most likely be used with a:
(a) DC yoke
(b) Split phase AC yoke
(c) Stationary magnetic particle unit
(d) Portable magnetic particle unit
(d) Portable magnetic particle unit
- The most common harmful effect of exposure to black light is:
(a) Eyeball fluorescence
(b) Burned retinas
(c) Skin burns
(d) None of the above
(a) Eyeball fluorescence
- Which of the following types of magnetic fields may be present without any external
evidence?
(a) Circular
(b) Longitudinal
(c) Secondary
(d) Tertiary
(a) Circular
- A residual circular field may be objectionable because:
(a) Grinding may produce cracks
(b) Machining may create external poles
(c) Heat treating may lead to tight surface cracks
(d) All of the above
(a) Grinding may produce cracks
(b) Machining may create external poles
(c) Heat treating may lead to tight surface cracks
(d) All of the above
- Which of the following is a disadvantage of magnetic particle 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 metals
(d) Works well through a thin coat of paint
