T.O. 33B-1-1
Glossary 11
(2)
“Solidification shrinkage” the reduction in volume of metal from the beginning to ending of solidification.
(3)
“Solid shrinkage” - the reduction in volume of metal from the solidus to room temperature.
(4)
“Total shrinkage” - the sum of the shrinkage in parts (1), (2) and (3).
CASTING STRAINS: Strains in a casting caused by casting stresses that develop as the casting cools.
CASTING STRESSES: Stressed set up in a casting because of geometry and casting shrinkage.
CAST-WELD ASSEMBLY: An assembly formed by welding one casting to another.
CATHODE (RT): The negatively biased electrode of an X-ray tube from which the electrons are emitted to be
accelerated to the anode.
CATHODE RAY (UT, RT): A stream of electrons emitted by a heated filament and projected in a more or less confined
beam under the influence of a magnetic and/or electric field.
CATHODE RAY TUBE (UT): A vacuum tube, containing a screen, upon which signals are displayed; basic display
device for an A-scan. Abbreviation is CRT.
CENTISTOKE: A unit of kinematic viscosity. Water has a viscosity of about one centistoke.
CENTRAL CONDUCTOR (MT): A conductor made of copper, aluminum, steel or flexible cable that is passed into or
through an opening in a cylindrically-shaped part or other shapes when applicable for the purpose of establishing a
circular field on the inside diameter.
CENTRIFUGAL CASTING: A casting made in a mold (sand, plaster, or permanent mold) which rotates while the
metal solidifies under the pressure developed by centrifugal force.
CERMET (PT): A strong alloy of a heat-resistant compound and a metal.
CERTIFIED DENSITY (RT): See STEP-WEDGE CALIBRATION FILM.
CESIUM-137: A radioactive isotope of the element cesium having a half-life of 80 years, plus or minus three years.
CESIUM-137 (RT): A radioactive nuclide of the element cesium having a half-life of 30 years, and photon energy of
882 KeV (which is 0.862 MeV).
CHAIN REACTION: A reaction that stimulates its own repetition. In a fission chain reaction, a fission nucleus
absorbs a neutron and fissions, releasing more than one additional neutron. These in turn can be absorbed by other
fissionable nuclei, releasing more neutrons. A fission chain reaction is self-sustaining when the number of neutrons
released in a given time interval equals or exceeds the number of neutrons absorbed.
CHALK TEST: The forerunner of modern penetrant methods. A method of locating cracks by applying oil to a part
and then removing the excess from the surface, which is then coated with whiting or chalk. After a short period of time
the oil seeps out of the cracks into the whiting, or chalk, causing an appreciable difference in whiteness. This method
has been replaced with more advanced penetrant methods for most applications.
CHARACTERISTIC CURVE (RT): A curve which expresses film density as a function of log relative exposure. These
curves are useful in determining exposure correction factors and to define the gamma characteristics of the film.
CHARACTERISTIC RADIATION (RT): X-radiation consisting of discrete wavelengths which are characteristic of the
emitting material.
