SUBSURFACE CORROSION: Formation of isolated particles of corrosion products beneath the metal surface. This
results from the preferential reaction of certain alloy constituents by inward diffusion of oxygen, nitrogen and sulfur.
SUB-SURFACE DEFECT: Any defect which does not break the surface of the part in which it exists.
SUBSURFACE INDICATION: Any indication that does not open onto the surface of the part in which it exists.
SUPERFICIAL ROCKWELL HARDNESS TEST: Form of Rockwell Hardness Test using relatively light loads, which
produce minimum penetration. Used for determining surface hardness or hardness of thin sections or small parts, or
where large hardness impression might be harmful.
SUPPRESSION (UT): See REJECT.
Condition of a surface as a result of a final treatment.
Measured surface profile characteristics, the preferred term being Roughness.
SURFACE INDICATION: Any indication that is open onto the surface of the part in which it exists.
SURFACE IRREGULARITY: An image on a radiograph film that corresponds to an irregularity visible on the surface
of an object being tested.
SURFACE IRREGULARITY (RT): An image on a radiograph that corresponds to an irregularity visible on the surface
of a specimen.
SURFACE IRREGULARITIES: Any change in material surface that renders the specimen unserviceable.
SURFACE TENSION (PT): That property due to molecular forces, by which the surface of all liquids tends to bring the
contained volume into a form having the least superficial area.
SURFACE WAVE (UT): A type of wave which travels along a surface; characterized by elliptical particle motion
having effective penetration less than one wave length.
SURFACTANT (PT): (Surface active agent) A soluble compound that reduces the surface tension of liquids, or reduces
interfacial tension between two liquids or a liquid and a solid.
SURGE METHOD (MT): Inspection by first employing a high surge of magnetizing force, followed by a reduced
magnetic field during application of a finely divided ferromagnetic inspection medium.
SURGE SUPPRESSOR: A device that automatically reduces abnormally high voltage or current transients to
SURVEY: An evaluation of the radiological conditions and potential hazards incident to the presence of radiation.
When appropriate, such an evaluation includes a physical survey of the location and measurements or calculations of
the levels of radiation.
SURVEY METER (RT): A portable instrument that measures dose rate of exposure or radiation intensity.
SUSPENSION (MT): The correct term applied to the liquid bath in which is suspended the ferromagnetic particles
used in the wet magnetic particle inspection method.