HOT SHORTNESS: Brittleness in metal in the hot forming range.
HOT SPOT: The point of retarded solidification caused by an increased mass of metal at the juncture of two sections. It
frequently results in shrinkage and inferior mechanical properties at this location.
HOT TEAR: A fracture formed in a metal during solidification because of hindered contraction. Usually on the surface
of the part.
HOT WORKING: Deforming metal plastically at such a temperature and rate that strain hardening does not occur.
The low limit of temperature is the recrystallization temperature.
HYDROGEN EMBRITTLEMENT: A condition of low ductility in metals resulting from the absorption of hydrogen.
HYDROMETER: An instrument used to determine specific gravity and hence the strength. It consists of a sealed,
graduated tube, weighted at one end, that sinks in a fluid to a depth used as a measure of the fluids specific gravity.
HYDROPHILIC (PT): Having an affinity for, attracting, adsorbing, or absorbing water. A substance soluble in water.
HYDROPHILIC REMOVER (PT): A water compatible remover used with standard penetrants. Provides for improved
control of the emulsification step process. It requires different processing steps than the standard Lipophilic
HYSTERESIS (MT): A retardation or lagging of the magnetic effect when the magnetizing forces acting upon a
ferromagnetic body are changed.
Hz: Abbreviation for hertz.
IACS (ET): International Annealed Copper Standard is an international standard of electrical conductivity. It is based
on a high purity grade of copper designated as 100 percent.
ICICLES (BURN THROUGH): A coalescence of metal beyond the root of the weld. IIW: Abbreviation for
International Institute of Welding.
IIW BLOCK: Specific type of reference standard used for angle beam, straight beam, and surface wave methods. See
IMAGE AMPLIFIER (RT): A device that enhances a radiographic image for the purpose of decreasing interpretation
time or increasing image detail.
IMAGE CONTRAST (RT): See CONTRAST, FILM.
IMAGE DEFINITION (RT): See DEFINITION, RADIOGRAPHIC.
IMAGE INTENSIFIER (RT): A device used in fluoroscopy to produce an image brighter than that, which would be
produced by the unaided action of the X-ray beam on a fluorescent screen.
IMAGE QUALITY INDICATOR (IQI) (PENETRAMETER) (RT): A device used to determine from the appearance of
its image in a radiograph, the overall quality of that radiograph. It is not intended for use in judging size nor
establishing acceptance limits for discontinuities.
IMAGE QUALITY LEVEL (RT): See RADIOGRAPHIC QUALITY LEVEL.