SAFELIGHT (RT): A special lamp used in the darkroom to provide working visibility without affecting the
photosensitive emulsion of the radiographic film.
SALT SCREEN (RT): See intensifying screen.
SALVAGE INSPECTION: Inspection for salvage parts that can be repaired.
SAMARIUM-145: A radioisotope of the element samarium.
SAMPLING INSPECTION: Inspecting a random sample from a lot of parts to determine the lot quality, the sample
size having been chosen in accordance with statistical methods.
SAND: A granular material resulting from the disintegration of rock. Foundry sands are mainly silica. Bank sands
are found in sedimentary deposits and contain less than 5% clay. Dune sand occurs in wind blown deposits near
large bodies of water and is very high in silica content. Moulding sand contains more than 5% clay; usually between
10 and 20%. Silica sand is a granular material containing at least 95% silica and often more than 99%. Sand core
is nearly pure silica. Miscellaneous sand includes zircon, olivine, calcium carbonate, lava, and titanium minerals.
SAND BLAST: (Grit Blast) The use of sand or grit at high velocity through air pressure to clean surfaces.
SAPONIFICATION (PT): The process of converting chemicals into soap; involves the alkaline hydrolysis of a fat or
oil, or the neutralization of a fatty acid.
SATURATION (MT): The point in the magnetization of a magnetizable object at which an increase in the magnetizing
force produced no increase in the magnetic field within the part. See VERTICAL SATURATION (SCOPE) (UT): A
term used to describe an indication of such a size as to reach full scope amplitude (100%). Beyond this point there is
no visual display to estimate the actual real height of the response signal unless the equipment is provided with dB
SCAB: A defect consisting of a flat volume of metal joined to a casting through a small area. It is usually set in a
depression, a flat side being separated from the metal of the casting proper by a thin layer of sand.
SCALE: Oxide formed on metal by chemical action of the surface metal with oxygen from the air.
SCALE PIT: Shallow surface depression in metal, caused by scale.
Forming a thick layer of oxidation products on metals at high temperatures.
Depositing water-insoluble constituents on a metal surface, as in cooling tubes and water boilers.
SCANNING (ET, UT): Relative movement of the search unit over a test part.
SCARFING: Cutting surface areas of metal objects, ordinarily by using a gas torch. The operation permits surface
defects to be cut from ingots, billets or the edges of plate that is to be beveled for butt welding.
SCATTER (RT): One of the causes of haziness or fog. Some of the incident radiation is scattered by atomic electrons
of the object being radiographed much as light is dispersed by fog. Any material, whether specimen, cassette, tabletop
walls, floors, etc., receiving direct radiation, is a source of scattered radiation.
SCATTER UNSHARPNESS (RT): See UNSHARPNESS.