ASTM A193 Grade B8M studs are manufactured from AISI 316 stainless steel, and tested to meet A193 B8M. Grade markings consists of both the grade symbol "B8M" 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 commonly in the 8UN Thread (8 threads per inch). Specified for use in pressure vessels, valves, flanges, and fittings for high temperature or high pressure service, or other special purpose applications.