T91/P91 is a ferritic chromium/molybdenum alloy that is microalloyed with vanadium and columbium (niobium) and has nitrogen. The first Super 9% Cr steel was originally approved and developed for superheaters and reheat superheaters. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, and machining. Filing Code: SA-465. Producer or source: Mannesman.