ASTM A193 specification covers alloy steel and stainless steel bolting material for pressure vessels, valves, flanges, and fittings for high temperature or high pressure service, or other special purpose applications.Several grades are covered, including ferritic steels and austenitic stainless steels designated B5, B8, and so forth. Selection will depend upon design, service conditions, mechanical properties, and high temperature characteristics.Material according to ASTM A193 B7 is often available in national coarse (UNC) thread pitches, if being used in traditional applications, threads are specified 8 threads per inch (tpi) for diameters above one inch.Below is a summary of a few of the common grades.

ASTM A193, Grade B16- a heat-treated chromium-molybdenum-vanadium steel for high-pressure, high-temperature service.