| 摘要 |
PROBLEM TO BE SOLVED: To provide a high strength ferritic heat resistant steel which has more excellent long time creep rupture strength compared with the conventional one for realizing a steel usable at a high vapor temperature of about 650 deg.C. SOLUTION: The ferritic heat resistant steel has a composition containing, by weight, 0.09 to 0.13% C, 0.20 to 1.0% Si, 0.05 to 1.5% Mn, 0.02 to 0.5% Ni, 9.0 to 13.0% Cr, 0.05 to 0.5% Mo, 0.5 to 3.0% W, 0.10 to 0.30% V, 0.04 to 0.2% Nb, 0.5 to 5.0% Co, 0.01 to 0.1% N, 0.001 to 0.030% B, <=0.01% Cu, and <=0.002% Al, and has a structure of a martensitic single phase by refining heat treatment such as normalizing and tempering heat treatment. Alternatively, the ferritic heat resistant steel has a composition in the above componential ranges, and has a dual-phase structure containing aδferritic structure of 1 to 15%, by volume ratio, in addition to the martensitic structure after the refining heat treatment. |
