ASTM A193 Grade B8 studs are manufactured from AISI 304 stainless steel, and tested to meet A193. Dimensional specifications are governed by ASME B18.31.2. Grade markings consists of both the grade symbol "B8" and the manufacturer's identification mark on one end of each stud 3/8" diameter and larger. Manufacturer's marking may be placed on other end if insufficient space. A193 grade B8 all thread studs having diameters above 1" are most common 8UN (8 threads per inch). For use in pressure vessels, valves, flanges, and fittings for high temperature or high pressure service, or other special purpose applications. A320 grade B8 studs available for low temperature service.