Understanding NRT- Reading 1- 2 of 2- Radiogaphic Testing A

Arc strike is an indication from a localized heat-affected zone or a change in
surface contour of a finished weld or adjacent base metal. Arc strikes are
caused by the heat generated when electrical energy passes between
surfaces of the finished weld or base metal and the current source.
Weld spatter occurs in arc or gas welding as metal particles which are
expelled during welding and which do not form part of the actual weld: weld
spatter appears as many small, light cylindrical indications on a radiograph.
Tungsten inclusion is usually denser than base-metal particles. Tungsten
inclusions appear most linear, very light radiographic images; accept/reject
decisions for this defect are generally based on the slag criteria.
Oxidation is the condition of a surface which is heated during welding,
resulting in oxide formation on the surface, due to partial or complete lack of
purge of the weld atmosphere. Also called sugaring.
Charlie Chong/ Fion Zhang