Non destructive testing Flashcards
non- destructive testing is sometimes referred to as ________________ or ___________________
non-destructive inspection (NDI) or non-destructive examination (NDE)
the five most common non-destructive testing methods are
visual inspection, dye penetrant, magnetic particle, ultrasonics and radiography
_________ is used to detect discontinuities open to the surface of solid and non-porous material
liquid penetrant testing (LPT)
A distinct advantage of the liquid penetrant is that it can surface defects in a wide variety of materials including?
metals, glass, ceramics and plastics
the major limitation of liquid penetrant inspection is that it can only detect imperfections that are ______
open to the surface
there are two basic types of liquid penetrants ________ and _________
fluorescent and visible
because of the vast differences among applications for liquid penetrant inspection, the systems are broadly classified as
the water-washable system
the post-emulsifiable systems
the solvent-removable systems
_________ are liquid used to make excess oily penetrant on the surface of a workpiece wate-washable
emulsifiers
Fluorescent penetrant testing detects surface imperfections such as
surface cracks in castings, welds and carbide tools,
shrinkage in castings and hot forgings, and
cracks in turbine blades and ceramic insulators
_____________ is a process used to detect surface and subsurface discontinuities, usually at depths not greater than 6mm. the process is limited to ferromagnetic materials and is commonly used on welds, large forgings, castings and other parts with rough surfaces
Magnetic particle inspection
the ___________________ is designed so water alone can wash the penetrant from the surface of the workpiece without a separate emulsification step.
water-washable penetrant system
________________ that are not water-washable are employed to ensure detection of minute discontinuities in some material
high-sensitivity penetrants
operations involved in the post-emulsifiable system
liquid penetrant, emulsifier, and developing
there are two types of emulsifiers?
oil-based and water-based
oil-based emulsifiers function by ____________
diffusion
the rate at which it diffuses into the oil penetrant establishes its _________
emulsification time
dry developers consist of ____________
fine, amorphous silica powder
you can either sprinkle the workpiece with dry iron powder or submerge it in a ________
liquid with suspended iron particles
____________ are available on various colours for contrast reasons
dry powder
the __________ suspended in the liquid solutionare fluorescent
iron powders
for flaws to be revealed, the magnetic field must be oriented at ___ to the direction of the defect
90degree
a straight piece of ________ has a pole at each end
magnetized material
because of magnetic lines of force within the bar magnet run the length of the bar, it is said to be ________________ or to contain a _____________
longitudinally magnetized / longitudinal field
an electromagnet loses its magnetism when the current is shut off, except for a very small amount called _____________
residual magnetism
for increased visibility, manufacturers coat particles with _______________
fluorescent pigment
a ___________ is a convenient source of ultraviolet light.
mercury vapour lamp
this type of lamp emits light that has a spectrum of several intensity peaks within a wide band of ____
wavelengths
_____________is the ability of a material to absorb light energy at one frequency and emit light of a different frequency
fluorescence
since _____ inclusions or holes aree less dense, the radiation passes through those areas more easily. that portion of the film is exposed more and is darker when the film is developed
slag
the two criteria that measure the quality of the radiograph are cantrast and definition ________ refers to different degrees of darkening on the film, which depends on the amount of radiation absorbed by different sections of the specimen under examination
contrast
__________ refers to the sharpness with which the image is projected on the film
definition
ultrasontic testing is routinely done on bolts and pins to a _____________
length of 20 feet
if a defect such as a slag inclusion is present the pulse of sound is reflected back to the transducer, picked up by the transducer and displayed on an _____________
oscilloscope
ultrasonic testing is used to measure the wall thickness of mertials in corrosive service or to determine plate thickness during fabriction. thicknesses are measured to an accuracy of ___ by measurung the length of time required for a sound beam to travel thrugh the test piece
1%
__________ is one of the most widely used methods of non-destructive inspection.
ultrasonic inspection
a _____ transfers the mechanical vibration energy in the ultrasonic waves to the test piece.
couplant (a gel substance, or oil or water)
_______ it can be used to test for surface and subsurface defects, irregularities and coating thicknesses, including deposits and sludge
eddy current testing
__________ are liquids used to make excess oily penetrant on the surface of a workpiece water-washable
emulsifiers
there are two types of emulsifiers
oil-based and water-based
oil-based emulsifiers function by
diffusion
the rate at which it diffuses into the oil penetrant establishes its
emulsification time
