Self Assessment Questions Flashcards
The speed with which a penetrant penetrates a surface flaw is influenced to the greatest extent by which property?
Viscosity
What is meant by the term cohesion?
The attraction, at a molecular level, that the particles of a material have towards each other
What is meant by the term adhesion?
The opposition, at a molecular level, that the particles of a material have towards each other.
(Attraction to molecules of a different make up)
What is the relationship between surface tension and LPI?
Low surface tension aids the penetrant in spreading out and helps achieve good coverage
A good penetrant shall have which characteristics for wetting ability and surface tension?
High wetting ability and high surface tension
Solubility is the principle that a penetrant can be what by a solvent?
Evaporated
Solvent ability is the ability of a penetrant to keep dye pigments in what?
Solution
Which method of LPI would be used for inspecting smaller parts or localized areas of an article/component?
Solvent Removable
How is the emulsification time determined when used a post-emulsification penetrant and lipophilic emulsifier?
Aluminum test blocks and TAM panels
Which method of applying emulsifier is not recommended?
Spraying
Which developer is commonly used with method C?
Wet aqueous
Specific Gravity of wet aqueous developers are measured by what?
Hydrometer
What is the maximum developer time for a non-aqueous developer, unless otherwise specified?
30 minutes
What type of developers are applied by immersion?
Water suspended
Fluorescent materials used in fluorescent penetrants respond most actively to radiant energy, of a wavelength of approximately what?
3650 angstroms
Which part of the eye is responsible for the sensitivity to the peak wavelength of black light used in fluorescent LPI?
The cones
Which method of penetrant testing would be more damaging to aluminum and magnesium if the part were not cleaned properly after inspection?
Solvent Removable
Between nickel, titanium, SS or all of the above, which of the following may be damaged when used at high temperature if chlorine is left in contact with its surface after liquid penetrant inspection?
Stain less steel
What is a commonly used method of checking on the overall performance of the penetrant material system?
Comparing two sections of artificially cracked specimens
Prior to PT of a previously machined soft metal part, which of the cleaning methods listed below would best remove any smeared metal that could mask discontinuities?
A) Acid etching
B) Shot peening
C) Alkaline cleaning
D) Water cleaning with detergents
Acid etching
What is the term used to describe the action of the developer in soaking up the penetrant in a discontinuity, to cause the max bleed out of the LP for the increased contrast and sensitivity?
Blotting
What is the most desirable method of removing excess WW penetrant after the necessary penetration time?
A coarse pressure water spray
Between unglazed ceramic and a plastic sheet, which cannot be tested by the LP test method?
Unglazed ceramic
What is not a generally accepted means for classifying penetrant systems?
The viscosity of the penetrant used
A continuous linear indication can be caused by which discontinuity?
Cracks
Which of the following is not a requirement for a cleaning solvent used to clean the surface of a test specimen prior to penetrant testing?
A) must be capable of dissolving oils
B) must not be flammable
C) must be free of contaminants
D) must leave minimum residue on surface
Must not be flammable
The inspection of a test specimen for discontinuities should take place when?
After the developer has been on the test specimen for the proper development time
Which of the following applies to fine, tight, surface cracks?
A) emulsification should be 2x normal
B) part should be cleaned VERY thoroughly to eliminate background
C) drying time short as possible
D) dev applied heavier than normal
Part should be cleaned very thoroughly to eliminate confusing background
When it’s necessary to detect small discontinuities, what will happen to the dwell time?
Longer than the dwell used to detect large discontinuities
What’s the difference in the sequence of steps taken to dry a piece that’s being inspected using a wet developer?
You dry AFTER you develop instead of before
A serious loss of water in a wet developer mix or excessive over-concentration of developer powder can cause what?
Cracking of the developer coating during the drying operation
What type of penetrant would be most difficult to rinse from threaded parts, keyways and blind holes?
Post emulsification fluorescent penetrants
Which of the following physical properties, more than any other, determines what makes a material a good penetrant?
A) viscosity
B) surface tension
C) wetting ability
D) no one single property determines if a material will or will not be a good penetrant
D) no one single property determines if a material will or will not be a good penetrant
Most commercial penetrants have a specific gravity of what?
Less than one
What is the best type of penetrant for locating wide, shallow discontinuities?
Post emulsification fluorescent penetrant
Which of the following discontinuities could produce a penetrant indication consisting of a series of aligned dots?
A) a tight crack
B) a wide or gross crack
C) an open seam
D) random porosity?
A) a tight crack
Which of the following discontinuities could be classified as a primary processing discontinuity often found in wrought material?
A) fatigue crack
B) stress-corrosion crack
C) porosity
D) machining tear
C) porosity
When conducting a penetrant test using water-washable penetrant, the approximate dwell time for an aluminum casting should be?
A) 5 to 15 min
B) 3 to 5 min
C) 20 to 25 min
D) 30 min
A) 5 to 15 min
When conducting a visible dye penetrant test for gross voids, where discontinuity indications will be large, the brightness level of the white light on the part in the inspection area should not be less than:
A) 30 to 50 lux
B) 100 to 200 lux
C) 320 to 540 lux
D) 750 to 1070 lux
C) 320 to 540 lux
If a penetrant test is to be conducted using a visible dye penetrant in pressurized spray cans, the temperature of the test area should not be lower than what?
A) 30•C
B) 15•C
C) 5•C
D) -7•C
B) 15•C
A wide crack will usually show up as a ________ penetrant indication:
A) continuous line
B) wide and fuzzy
C) bulbous
D) dotted line
A) continuous line
The penetrant testing indication for a cold shut on the surface of a casting will normally be:
A) a dotted line
B) a cluster of small indications
C) a smooth continuous line
D) a large bulbous indication
C) a smooth continuous line
The penetrant testing indication of a forging lap will normally be:
A) a round or nearly round indication
B) a cluster of indications
C) a continuous line
D) a dotted line
C) a continuous line
When conducting a penetrant test on a forging, an indication in the form of an intermittent line could be indicative of:
A) porosity
B) segregation
C) a cold shut
D) a partially welded lap
C) a cold shut
Which of the following is NOT a defect that may occur in almost any type of sand casting?
A) shrinkage cracks
B) laps
C) cold shut
D) surface sand inclusions
B) laps
Of the methods listed below, the most effective means of precleaning a test item prior to a penetrant test is:
A) Vapor degreasing
B) detergent cleaning
C) steam cleaning
D) solvent wipe
A) Vapor degreasing
Which of the methods listed below is most sensitive for detecting fine, right surface cracks?
A) visible WW
B) visible PE
C) fluorescent WW
D) fluorescent PE
D) fluorescent PE
The maximum air temperature of hot air dryers used in a penetrant system should not exceed:
A) 40•C
B) 65•C
C) 90•C
D) 120•C
D) 120•C
Which of the following is not an important property that all penetrants must possess?
A) fluidity
B) viscosity
C) volatility
D) wettability
C) volatility
Which of the following statements is NOT a valid basis for making a choice between a wet or dry developer?
A) dry developer is easier to apply with automatic equipment
B) dry developer is usually easier to apply to very large parts
C) when cleaning has been accomplished by wiping, or with a solvent, and no hot air drying is available, dry developer is usually more convenient
D) wet developer is easier to apply to a large number of small parts using basket handling
A) dry developer is easier to apply with automatic equipment
Which of the following is NOT an important reason why developers are supplied in pressurized cans?
A) to make PT portable
B) to make it easy to keep powder in suspension
C) to make it possible to get developer in areas that would be difficult to get to by any other method
D) to facilitate production testing of large quantities of parts
D) to facilitate production testing of large quantities of parts
Prior to PT of a previously machined soft metal part which of the cleaning methods listed below would best remove any smeared metal that could mask discontinuities?
A) etching
B) shot peening
C) alkaline cleaning
D) water cleaning with detergents
A) etching
When using a fluorescent, post emulsifier penetrant, the length of time the emulsifier is allowed to remain in the part is critical when detecting shallow scratch-like discontinuities. The best length of time should be:
A) 10 seconds
B) 5 min
C) 2 to 3 min
D) determined by experimentation
D) determined by experimentation
When conducting a penetrant test in accordance with the ASME code, dye penetrant indications should be interpreted not later than how long after the developer has been applied?
30 minutes
In most cases, the best test method of those listed below for testing the surface of porous materials is what?
A) MPI
B) filtered particle testing
C) WW PT
D) visible dye PT
B) filtered particle testing
The sulphur and chlorine found in penetrant material are detrimental to:
A) aluminum
B) iron
C) nickel
D) magnesium
C) nickel
Which of the following statements apply to post-emulsifiable penetrants?
A) PE penetrants have good penetrating characteristics and are soluble when washed with solvents
B) PE penetrants have good penetrating characteristics but are not soluble in water or solvents
C) PE penetrants have poor penetrating characteristics but are soluble in either water or solvents
D) none of the above apply
A) PE penetrants have good penetrating characteristics and are soluble when washed with solvents
In general, which of the following types of discontinuities would require the longest penetration time?
A) laps in forgings
B) fatigue cracks in plastic
C) grinding cracks
D) heat treat cracks
A) laps in forgings
Which of the following production techniques or conditions is NOT likely to cause non relevant indications?
A) poor surface prep
B) press fit parts
C) improper washing or rinsing of penetrant
D) improper heat treatment of a test specimen
D) improper heat treatment of a test specimen
When penetrant testing nickel alloys, the materials used in the penetrant system should NOT contain any significant quantities of:
A) carbon or oil
B) sulphur or chlorine
C) emulsifier or oil
D) fluorescent agent
B) sulphur or chlorine
A 100mm long aluminum part, which is “m” shaped in cross section, has been bent quite sharply near the centre. The part has been heated, press straightened, and penetrant tested after rework. A sharp, well defined indication in the form of a lab irregular line running from the outer edge of one flat section perpendicular to the parts long axis is noted. The most probable cause of this indication is:
A) straightening cracks
B) a pipe
C) a lap
D) grinding cracks
A) straightening cracks
Numerous fluorescent indications are observed in a gate cut-off area of a casting. Which of the discontinuities below could cause such indications?
A) quench cracks
B) gas porosity
C) hot tears
D) shrinkage
D) shrinkage
If a part is to be both penetrant tested and pressure tested:
A) the pressure test should be done before the PT
B) the PT should be done before the pressure test
C) all discontinuities discovered during the pressure test must be repaired before the PT is conducted
D) all parts must be both pressure tested and PT’d before the part is rejected
B) the PT should be done before the pressure test
A broken forged block locking flange is repaired by welding. PT reveals an irregular linear indication located near the centre of the weld repair bead. It is oriented linearly in the weld direction except that it turns off from the axial direction at either end. Which could cause such an indication?
A) weld overlay
B) welding shrink
C) quenching cracks
D) lap
B) welding shrink
What’s another name for aqueous developer?
Water suspended developer
What’s another name for solvent suspendible developers?
Non-aqueous developer
In NDT, PT was originally developed primarily to inspect what?
A) automotive components
B) light alloys used in aircraft
C) welds
D) native pottery
B) light alloys used in aircraft
The single most important factor contributing to the sensitivity of a penetrant to fine cracks is:
A) handling technique
B) type of developer
C) type of penetrant
D) see ability
D) see ability
The main reason for choosing the colour red for colour contrast is what?
A) it’s high degree of colour contrast
B) it’s high degree of solubility in most penetrant liquids
C) both a and b
D) none of the above
C) both a and b
The penetrant technique employing a solvent suspension developer with a low intensity fluorescent agent is called:
A) the leaker technique
B) reversed fluorescence
C) oil and whiting
D) normal wet development
B) reversed fluorescence
Compared to fluorescent penetrants, the amount of dye in colour-contrast penetrants is:
Much higher
A safety advantage of most dyes is that they have:
A) low toxicity
B) low flash point
C) chemical inertness
D) low volatility
A) low toxicity
Removal of developer powder is:
A) essential in all situations
B) never required
C) a health consideration
D) none of the above
D) none of the above
Water suspendible developer, if required to be removed, is best removed by:
A) sand blasting
B) warm water and detergent
C) tri-chlorenthanal
D) steam cleaning
B) warm water and detergent
In addition to providing quick drying developer, solvents in solvent suspendible developers:
A) aid in post cleaning
B) eliminate the need for emulsifiers
C) dissolve penetrant and give it greater mobility
D) none of the above
C) dissolve penetrant and give it greater mobility
On smooth surfaces, the best developer to use with fluorescent penetrants is:
A) solvent suspendible
B) water suspendible
C) dry-regular
D) dry-fluffy
B) water suspendible
The removal of excess penetrant by rag wipe is most effective on:
A) welds
B) cast aluminum
C) glass
D) cast steel
C) glass
MAX water temp for removal of PE penetrant is:
A) room temp
B) 40•F
C) 110•F
D) 100•C
C) 110•F
When using fluorescent penetrants, a black light is often placed at the:
A) penetrant station
B) developer station
C) removal or wash station
D) none station
C) removal or wash station
The most effective mean of drying a part is:
A) cloth wipe
B) hot air
C) use of volatile solvents
D) compressed air blasts
B) hot air
Penetrant tends to come out of surface openings more rapidly when:
A) the part is vibrated
B) the part is heated
C) the penetrant is fluorescent
D) developer is wet
B) the part is heated
Air temperature in a recirculating air dryer is generally recommended to be:
A) just over the boiling point of water
B) 40•C
C) 100•F
D) 400•F
A) just over the boiling point of water
Where parts are few or large, the preferred developer is:
A) water soluble
B) water suspendible
C) solvent
D) dry powder
D) dry powder
Which is not an advantage of wet developer?
A) easy to apply large numbers of small parts
B) completeness of coverage
C) sharper definition
D) easy to apply to very large parts
D) easy to apply to very large parts
Occasional exposure of skin to penetrants will usually result in:
A) cancer
B) irritation
C) no noticeable effect
D) caustic burns
C) no noticeable effect
Because of emulsifiers in water-washable penetrants, they have been used to wash greasy hands
A) this deteriorates the penetrant
B) the operator may get cancer
C) the operator may get sore hands
D) subsequent tests are less sensitive
C) the operator may get sore hands
In leak detection using liquid penetrants, the best penetrating ability is had using:
A) WW colour contrast
B) WW fluorescent
C) PE penetrant
D) all penetrants are about the same
C) PE penetrants
To verify a leak location when performing penetrant leak detection….
A) the operator waits for a drip to form
B) developer is added and the pattern observed
C) the test is re-run with a different colour dye
D) the wet spot is wiped off and watched for re-appearance
D) the wet spot is wiped off and watched for re-appearance
Recommended inspection temperature for the penetrant bath is:
A) 70•F
B) 70•C
C) 110•F
D) 40•F
A) 70•F
The expendable penetrant technique is used on:
A) small parts
B) government jobs
C) aircraft
D) local areas of large parts
D) local areas of large parts
When a small diameter tube is placed in a glass of water, water rises in the tube to a level above the adjacent surface. This is called:
A) viscosity
B) capillary action
C) surface tension
D) barometric testing
B) capillary action
How is the size of a LP indication usually related to the discontinuity it represents:
A) larger than
B) smaller than
C) equal to
D) not related to
A) larger than
A wire brush should be used for pre-cleaning:
A) when grease and oil must be removed
B) only as a last resort
C) when rust is to be removed
D) when grinding burrs must be removed
C) when rust is to be removed
What is the preferred method of removing paint prior to performing a penetrant testing?
A) sand blast
B) chemical removers
C) power wire brush
D) shot blast
B) chemical removers
Which of the following chemical elements are normally held to a minimum in LP materials, when testing stainless steel and titanium?
A) hydrogen
B) chlorine
C) carbon
D) oil
B) chlorine
Which of the following chemical elements are normally held to a minimum in LP materials when testing nickel based alloys?
A) sulphur
B) oxygen
C) carbon
D) nitrogen
A) sulphur
A developer aids penetrant bleed out because of:
A) adequate removal of the excess penetrant
B) providing a contrasting background for visible dye indications
C) capillary action
D) proper emulsification action
C) capillary action
Water based wet developer is applied:
A) immediately before removal of excess penetrant
B) immediately after removal of excess penetrant
C) after a drying period following removal of excess penetrant
D) for max sensitivity results
B) immediately after removal of excess penetrant
Non-aqueous wet developer is applied:
A) immediately before removal of excess penetrant
B) immediately after removal of excess penetrant
C) after excess penetrant is removed and part surface is dried
D) for max sensitivity results
C) after excess penetrant is removed and part surface is dried
Typical ranges of emulsifier dwell times are:
A) 5 to 10 minutes
B) 30 seconds to 1 minute
C) 1 to 3 minutes
D) 5 to 10 minutes
C) 1 to 3 minutes
What action is necessary if the penetrant is inadvertently allowed to dry on the test piece?
A) repeat the test, beginning with the pre-cleaning operation
B) re-wet the penetrant, begin dwell time again and continue
C) clean the penetrant off the surface and develop manually
D) clean the penetrant off the surface, wait 5 min and develop normally
A) repeat the test, beginning with the pre-cleaning operation
Which type of emulsifier is designed to be used as a ‘scrubber’?
A) hydrophilic
B) hydrophobic
C) lipophilic
D) fluoroscopic
A) hydrophilic
When using a hydrophilic emulsifier, the amount of penetrant removed is most affected by:
A) solution strength and time of spray
B) penetrant dwell time
C) emulsifier dwell time
D) adequacy of pre-clean
A) solution strength and time of spray
If a mercury vapour arc black light is inadvertently turned off, how soon may it be restarted?
A) immediately
B) 5 min
C) 10 min
D) 15 min
C) 10 min
Which penetrant process is best suited to the detection of discontinuities in a test piece having threads and key ways?
A) solvent removable
B) water washable
C) PE
D) fluorescent
B) water washable
Which penetrant process is best suited to detect shallow discontinuities?
A) solvent removable
B) WW
C) PE
D) fluorescent
C) PE
Which penetrant process is the most sensitive to detect fine discontinuities?
A) solvent removable
B) WW
C) PE fluorescent
D) WW fluorescent
C) PE fluorescent
Which penetrant process should be used if repeated examinations are anticipated?
A) solvent removable
B) WW
C) PE
D) fluorescent
A) solvent removable
What is likely the result of looking directly into a black light?
A) burning of the retina of the eye
B) temporary inflammation of the cornea
C) long term tendency toward formation of cataracts
D) fluorescence of the fluid in the eye
D) fluorescence of the fluid in the eye
Which type of penetrant process affords most control of test sensitivity level?
A) solvent removable
B) WW
C) PE
D) fluorescent
C) PE
Which type of penetrant process is least susceptible to over washing?
A) solvent removable
B) WW
C) PE
D) fluorescent
C) PE
Aside from increasing the integrity and safety of manufactured pieces, NDT cuts costs by:
A) increasing production rates
B) reducing personnel
C) eliminating poor stock prior to processing
D) all of the above
C) eliminating poor stock prior to processing
The ability of a liquid to wet a surface is measured by the contact angle, i.e. the angle between the liquid and the surface at the point of contact as the liquid advances. Good penetrants should have:
A) a very small contact angle
B) a very large contact angle
C) a contact angle of approximately 45•
D) a contact angle greater than 90•
A) a very small contact angle
What is chemical inertness?
A substance that is not chemically reactive
A good penetrant must be:
A) inert with respect to the material being tested
B) highly viscous
C) highly volatile
D) an inorganic base liquid
A) inert with respect to the material being tested
Which factor does not determine the liquid penetrant technique to be used?
A) expected service of part
B) form and stage of manufacture of the part
C) expected defect orientation
D) cost of inspection
C) expected defect orientation
Viscosity is used to determine drag out. Units used to measure viscosity are:
A) poundals
B) m/sec
C) centristokes
D) milligravs per cc
C) centristokes
The preferred colour for liquid penetrants used in leak detection is what?
Red
Which of the following statements is correct?
A) the HAZ is basically a homogenous structure
B) in some areas of the HAZ, grain size can be smaller than in the unaffected base metal
C) the temp in the HAZ can sometimes exceed temp in fusion zone
D) transverse cracks do not occur in the HAZ
B) in some areas of the HAZ, grain size can be smaller than in the unaffected base metal
Metal forming such as rolling results in:
A) plastic flow of the metal
B) elongation of existing defects perpendicular to rolling direction
C) directional properties which are always beneficial for secondary forming operations
D) flattening out of defects which makes them more easily detectable by most NDT methods
A) plastic flow of metal
Which of the following is not a cause of undercutting?
A) excessive amperage
B) excessive travel speed
C) excessive electrode diameter
D) excessive restraint during welding
D) excessive restraint during welding
An extremely thin discontinuity that is the result of pipes, or inclusions flattened and made directional by working is called:
A) a stringer
B) a lamination
C) a seam
D) a cold shut
B) a lamination
In general, where can you find heat treat cracks?
A) at the centre of the weld
B) in areas of sudden change in thickness
C) on a cast plate
D) all the above
B) in areas of sudden change in thickness
A somewhat linear intermittent penetrant indication would be formed by a:
A) crater crack
B) hot tear
C) forging lap
D) a cold shut
B) a forging lap
All indications found by NDT methods are:
A) rejectable
B) direct
C) indirect
D) dimensionally correct
C) indirect
The term defect or flaw indicates:
A) a minimum or maximum size
B) suitability of the part for a given purpose
C) nature of the fault
D) none of the above
D) none of the above
Plastic film developers are used:
A) on plastics only
B) for maximum sensitivity
C) if permanent records are wanted
D) all of the above
C) if permanent records are wanted
What is solubility?
The ability to be removed
What is solvent ability?
The ability to hold a dye
What is emulsifiability?
The ability to wash with water
What is inertness?
Tendency to remain stable under a wide range of conditions
What is flash point?
The lowest temp at which will give off a vapour
What is volatility?
Ease with which a material evaporates
What is the ratio of emulsifier and water in the Hydrophilic method?
20% hydrophilic emulsifier and 80% water
‘Forms’ relate to which step of the process?
Developer
What are the 4 Forms in order?
A: dry powder
B: water soluble
C: water suspendible
D: non-aqueous
What is the visible light spectrum?
400-700 nanometers
UVA, also known as black light, is what wavelength?
320-400 nm
What tool is used to verify emulsifier concentration?
Refractometer
What is LOX?
Liquid Oxygen Penetrant: used where combustion liquids can’t be tolerated
Ex. Rocket engines
What tool measure the concentration of the water suspended developer?
Hydrometer
What is a thixotropic penetrant?
It’s applied at a solid/gel and changes to a liquid after application
