The ferritic heat resisting steel null which is superior in tenacity and creeping

摘要

PURPOSE:To provide the steel with excellent creep strength and toughness by adding specified amounts of W, Zr, B and N to a heat-resistant steel having specified compsn. CONSTITUTION:The compsn. of the ferritic heat-resistant steel is constituted of, by weight, 0.01 to 0.03% C, 0.01 to 0.80% Si, 0.10 to 1.50% Mn, 8.00 to 13.00% Cr, 0.20 to 3.00% W, 0.005 to 1.00% Mo, 0.05 to 0.50% V, 0.02 to 0.12% Nb, 0.0003 to 0.008% B, 0.0005 to 0.10% Zr, 0.01 to 0.10% N, 0.0005 to 0.050% Al, =0.050% P, =0.010% S, =0.020% O and the balance Fe with inevitable impurities. If required, 0.05 to 1.00% Ni or one or both of 0.01 to 1.00% Co and 0.01 to 0.10% Ti are furthermore incorporated thereto. The steel has excellent weldability, etc., since the increase of high temp. strength corresponding to high temp. and high pressure in equipment can be attained.