ACOUSTIC EMISSION
Transient elastic waves resulting from local internal micro-displacements in a material
ACOUSTIC EMISSION ACTIVITY
Number of
... [Show More] bursts ( or events, if the approriate conditions are fulfilled) detected during test or part of test
ACOUSTIC EMISSION EVENT
Micro-structural displacement that produces elastic waves in a material under load or stress
ACOUSTIC EMISSION TESTING ( AE )
Passive NDT method that monitors a component or assembly for transient elastic waves into electrical signals. Acoustic waves may be movement of micro-structural dislocations during crack propagation, melting, phase transformation or thermal stresses.
ACOUSTIC IMPEDANCE
Frequency dependent property of a medium through which acoustic waves propagate in units of kg.s-1.m-2. in its simplest form, acoustic impedance is the product of longitudinal ultrasonic wave velocity and material density.
RADIOGRAPHIC ACTIVATION
the process by which neutrons bombard stable atoms and make them radioactive.
RADIOGRAPHIC ACTIVITY
Degree of radioactivity of a particular isotope. expressed as the number of atoms disintegrating per unit of time.
AGING
Heat treatment method that alter material properties and micro structures because of the duration of time at ambient or elevated tempature
ALTERNATING CURRENT
Electric current whose waveform changes cyclically in magnitude and direction
ALTERNATING CURRENT MAGNETIZATION
in mag-particle testing, a technique for inducing an active magnetic state by a cyclically reversing wave form, a state generally characterized by its form following ability and by shallow penetration.
AMPERE
SI unit of electric current
ANISOTROPY
Material characteristic in which different values of a property are noted in different directions
ANNEALING
process of heating a material to, and holding at, a desired temperature followed by cooling at a desired rate, usually to reduce residual stresses or bring about some other desired change.
ANODE
(1) in radiography, the positive electrode of a cathode ray tube that generates ionizing radiation. (2) positively charges terminal , which may corrode electrochemically during production of a electric current.
A-SCAN
one-dimensional display of ultrasonic echo amplitude as function of time or depth in test subject.
ASNT
American Society for Nondestructive Testing
ATTENUATION
(1) decrease in energy or signal magnitude in transmission form one point to another. (2) Decrease in intensity caused by absorption, leakage, reflection, scattering or other material characteristics.
BECQUEREL (Bq)
SI unit for measurement of radioactivity, equivalent to one disintegration per second
BETA PARTICLE
Electron or positron emitted from a nucleus during radioactive decay
BOUNDARY ECHO
Reflection of an ultrasonic wave for the interface
BRAZING
Joining of metals and alloys by fusion of nonferrous alloys that have a melting point above 806 F. but below melting points of materials being joined.
BROAD BAND
having a relatively wide frequency bandwidth. Used to describe pulses that display a wide frequency spectrum and receivers capable of amplifying them.
B-SCAN
two-dimensional view of a cross sectional plane through the test subject.the horizontal sweep is proportional to the distance along the test object and vertical sweep is proportional to depth, showing the front and back surfaces and discontinuities between.
CANDELA
SI unit for luminous intensity
THERMAL CAPACITANCE
Amount of heat that an object can store
HEAT CAPACITY
Ability of a material or structure to store heat. The denser the material generally will have higher heat capacity
CAPILLARY ACTION
Tendency of liquids to penetrate or migrate into small openings, such as cracks, pits. the positive force that causes movement of certain liquids along narrow or tight passages.
CASTING DIE
(1) casting used in a reusable metallic cavity (2) Casting process where molten metal is forced under high pressure into the cavity of a metal mold.
INVESTMENT CASTING
Casting metal into a mold produced by surrounding (investment : wax, plastic, frozen mercury) an expandable pattern with a refractory slurry that sets at room temp after which the "investment" is removed.
CATHODE
The negative electrode of an X-ray tube, the electrode from which electrons are emitted
CEMENTITE
hard brittle compound of iron and carbon known chemically as iron carbide and found in steels and cast irons.
CENTRIFUGE TUBE
Vial that holds liquids and has graduations to indicate the concentration of solids that settle out of a known suspension volume.
CERTIFICATION
written testimony that an individual has met the qualification requirements of a specific practice or standard.
CHAPLET
metal support used to hold a "core" in place on a mold.
CHARGE COUPLE DEVICE (CCD)
solid state image sensors.
CHATTER
in machining or grinding, vibration of tool, wheel or work piece producing a wavy surface on the work.
CHILL
metal insert embedded in the surface of a sand mold or core or placed in a mold cavity to increase the cooling rate at that point.
CIRCUMFERENTIAL
direction around the perimeter of a cylindrical surface.
CODE
standard enacted or enforced as a law
COEFFICIENT OF THERMAL EXPANSION (CTE)
rate of expansion or contraction per unit of length, volume or area per degree of temp change between specific lower or upper temp limits.
COERCIVE FORCE
reverse external magnetic field intensity required to reduce the test objects bulk magnetism to zero
ABSOLUTE COIL
a coil that response to the electromagnetic properties of that region of the test object within the magnetic field of the coil, without comparison to the response of a second coil at a different location on the same material.
BOBBIN COIL
cylindraically would absolute or differential probe useful for inspecting the inside diameter or tubular products.
DIFFERENTIAL COIL
two or more physically adjacent and mutually coupled coils connected in series opposition such that the imbalance between them causes a signal
COLT SHUT
(1) casting discontinuity caused by two streams of semimolten metal coming together withen a mold but failing to fuse. (2) a crack like discontinuity caused by forging, where two surfaces of metal fold against each other without joining.
COLD WORKING
permanent deformation produced by an external force in a metal below its recrystallization temp.
COLLIMATOR
in radiographic. A device for restricting the size, shape, and direction of the irradiating beam
PENETRANT COMPARATOR
(1) transparent plastic devise containing lines of known lengths used to evaluate indication dimensions. (2) An aluminum block with artificial cracks or special surface conditions to test different penetrants.
CONDUCTANCE
(1) in leak testing, the flow characteristics of a tube, manifold or leak path. (2) transmission of electric current through material
CONDUCTION
heat transfer occurring when more energetic particles collide with- and thus impart some of their heat energy to slower moving particles.
THERMAL CONDUCTIVITY
material property defining the relative ability to carry heat by conduction in a static temp gradient. differs in solids,liquids,vapors. it is high for metals and lower for gasses.
CONTACT METHOD (ULTRASONIC TESTING)
A ultrasonic transducer face makes direct contact with the test object through a thin film or couplant.
CONTINUOUS CASTING
manufacturing method in which ingot, billet, or tube is continuously solidified while being poured so that its length is not determined by mold dimensions.
CORNER EFFECT (ULTRASONIC TESTING)
strong reflection obtained when a ultrasonic beam is directed toward the intersection of two or more intersecting surfaces.
COSINE LAW
physical law stating that the illumination of a surface varies as the cosine of the incidence angle. Maximum illumination is obtained where the cosin equals one and when the source is perpendicular to the surface.
COUPLED
(1) two electric currents having an impedance in common so that a current in one causes a voltage in the other (2) two coils sharing parts of their magnetic flux paths
COUPLING (ELECTROMAGNETIC TESTING)
percentage of magnetic flux from a primary circuit that links a secondary circuit. effectiveness of a coil in inducing eddy currents in the test object.
CRITICAL ANGLE (ULTRASONIC TESTING)
incident angle of the ultrasonic beam where the refracted beam is parallel to the surface and above which a specific mode of refraction energy no longer exists.
C-SCAN
acoustic data displaying an image of two-dimensional test object with scaled grays or colors representing the ultrasonic signals.
DEAD ZONE ( ULTRASONIC TESTING)
interval following the initial pulse at the surface of a test object to the nearest inspection depth. any interval following a reflected signal where additional signals cannot be detected.
NONAQUEOUS WET DEVELOPER
fine particles suspended in a volatile solvent that assists bleedout by diluting the penetrant.
SOLUBLE DEVELOPER
fine particles completely soluble in its carrier that dries to form an absorptive coating.
SUSPENDIBLE DEVELOPER
fine particle suspended in water and that dries to an absorptive coating. Applied to the [part after removal of excess liquid penetrant and before drying.
DIFFRACTION (ULTRASONIC TESTING)
deflection of a wave front when passing the edge of an ultrasonically opaque object.
DUCTILITY
ability of a material to undergo plastic deformation without fracture.
DYNAMIC RANGE (ULTRASONIC TESTING)
ratio of maximum to minimum reflective areas that can be distinguished on the display at a constant gain setting.
EMULSIFIER
liquid that mixes with a oily penetrant such that the mixture can then be washed away with water.
HYDROPHILIC EMULSIFIER
water based liquid that interacts with the liquid [Show Less]