ASTM A193 Grade B7 is the standard material specification for chromium-molybdenum alloy steel fasteners for high-strength, high-temperature, and special-purpose applications. Grade B7 is a heat treated chromium molybdenum alloy steel with a minimum tensile requirement of 100 ksi, a yield strength of 75 ksi and a maximum hardness of 35 HRC. The ASTM A193 specification covers requirements for chemical composition, mechanical properties, hardness, heat treatment, and recommended nut washers for Class B7 fasteners. ASTM A193 Grade B7 is the broadest specification for fasteners, commonly found in bolts or pipes, pressure vessels, valves, flanges and fittings.