1.1 This specification2 covers 8 and 9?% nickel-alloy steel forged or rolled flanges, fittings, valves, and parts intended for use This specification covers the 8 and 9% nickel-alloy steel forged or rolled flanges, fittings, valves, and parts intended for use in welded pressure vessels for low-temperature service. Two types of materials are specified according to the chemical comp