RESIDUAL METHOD (MT): Bath is applied after current has been shut off; that is, the indicating particles are on the
part when residual (remaining) magnetic field is present.
RESIDUAL STRESS: Stress present in a body that is free of external forces or thermal gradients.
The amount of energy per unit volume released upon unloading.
The capacity of a metal, by virtue of high yield strength and low elastic modulus, to exhibit considerable
elastic recovery upon release of load.
RESISTANCE: Resistance is the opposition to the flow of an electrical current through a conductor. Its unit is the
RESOLUTION (RT): The smallest distance between adjacent distinguishable images on a radiograph or viewing
screen. It may be expressed as the number of lines (or line parts) per millimeter that can be seen as discrete images.
RESOLVING POWER (UT): The measure of the capability of an ultrasonic system to separate in time two
discontinuities at slightly different distances or to separate the multiple reflections from the back surface of flat plates.
RESONANCE (UT): The condition in which the frequency of the forced vibration (ultrasonic wave) is the same as the
natural frequency of the body (test piece) which results in abnormally large amplitudes of vibration.
RESONANCE METHOD: A technique in which continuous ultrasonic waves are varied in frequency to identify
resonant characteristics in order to discriminate some property of a part as thickness, stiffness, or bond integrity.
RESONANT FREQUENCY: The frequency at which a body will vibrate freely after being set in motion by some
RESTRAINER (RT): The constituent (e.g., potassium bromide) that reduces the activity of the developing agent but
enhances its preferential action by reducing the rate of development of unexposed grains to a greater extent than it does
that of exposed grains. It thus tends to reduce chemical fog.
RESTRICTED AREA: Any area access to which is controlled by the licensee.
Striking a trimmed but slightly misaligned or otherwise faulty forging one or more blows to improve
alignment, improve surface, maintain close tolerance, increase hardness or to effect other improvements.
(2) A sizing operation in which coining or stretching are utilized to correct or alter profiles and to counteract distortion.
RESULTANT (VECTOR FIELD) (MT): When two or more magnetizing forces operating in different directions are
simultaneously applied to a ferromagnetic material, a resultant field is produced, having a direction which is
determined by the relative strengths and directions of the applied magnetizing forces. Such a field is also referred to as
a vector field. If either or both of the applied magnetizing forces are themselves varying in direction or amount, the
resultant field is moving or swinging in direction and strength. Such a moving resultant field is sometimes referred to
as a swinging field.
RESIDUAL METHOD (MT): The method in which magnetic particles are applied to the material after the
magnetizing current has been discontinued.