1.1 This specification covers stainless and alloy-steel bolting specially heat treated for high-temperature service, such as steam turbine, gas turbine, and similar uses. See Specification This specifications covers alloy-steel bolting material specially heat treated for high-temperature service, such as steam turbine, gas turbine, and similar uses. The grades of steels covered here are: Grade B4B, Grade B4C, and Grade B4D. Steels of Gra