T.O. 33B-1-1
Glossary 72
RECEIVER (UT): Search unit or transducer element, used to receive ultrasonic energy from a test part.
RECESS: A groove or depression in a surface.
RECIPROCITY LAW (RT): Law that states that the film blackening is determined by the product of the milliamperage
or source strength and the time of exposure. See RECIPROCITY LAW FAILURE.
RECIPROCITY LAW FAILURE (RT): A term used to describe situations in which the reciprocity law is not
applicable. For very short or very long exposures, problems with film response time can cause the reciprocity law to
fail.
RECORDING MEDIUM (RT): A photographic film or other material that converts radiation energy into a permanent
visible image.
RECOVERY TIME: The time required for a test system to return to its original state after it has received a signal.
RECRYSTALLIZATION:
(1)
The change from one crystal structure to another, as occurs on heating or cooling through a critical
temperature.
(2)
The formation of a new, strain-free grain structure from that existing in cold worked metal, usually
accomplished by heating.
RECTIFICATION: Any method by which a unidirectional voltage can be obtained from an alternating supply.
RECTIFIED ALTERNATING CURRENT: By means of a device called a rectifier, which permits current to flow in
one direction only, alternating current can be converted to direct or unidirectional current. This differs from direct
current in that the current value varies from a steady level. This variation may be extreme, as in the case of half-wave
rectified single-phase AC or slight, as in the case of three-phase rectified AC
RECTIFIER: A tube or circuit capable of converting the high voltage alternating waveform into a usable unidirectional
voltage waveform.
REDUCTION:
(1)
In cupping and deep drawing, a measure of the percentage decrease from blank diameter to cup
diameter or of diameter reduction in redraws.
(2)
In forging, rolling and drawing, either the ratio of the original to final cross-sectional area or the
percentage decrease in cross-sectional area.
REDUCTION FACTOR: Dose rate without a shield divided by the dose rate with a shield interposed between a source
and a point at which radiation is measured.
REDUCTION OF AREA:
(1)
Commonly, the difference expressed as a percentage of original area, between the original cross-sectional
area of a tensile test specimen and the minimum cross-sectional area measured after complete separation. (2) The
difference expressed as a percentage of original area, between original cross-sectional area and that after straining the
specimen.
