Heat-resistant, ferritic steel with a low cr - and mn - content and with excellent strength at high temperatures

摘要

PROBLEM TO BE SOLVED: To obtain a low Mn, low Cr ferritic steel excellent in high temp. strength by specifying a composition consisting of C, Si, Mn, Ni, Cr, W, V, Nb, Al, Mg, B, N, P, S, Ti, and Fe. ;SOLUTION: The low Mn, low Cr ferritic steel excellent in high temp. strength can be obtained by providing a composition which consists of, by weight, 0.020-0.20% C, ≤0.7% Si, 0.1% Mn, ≤0.8% Ni, 0.8-3.5% Cr, 0.01-3.0% W, 0.1-0.5% V, 0.01-0.20% Nb, 0.001-0.05% Al, 0.0005-0.05% Mg, 0.0005-0.01% B, 0.05% N, ≤0.03% P, ≤0.015% S, 0.001-0.05% Ti, and the balance Fe with inevitable impurities and further contains, if necessary, prescribed amounts of Mo, La, Ce, Y, Ca, Ta, and Zr and in which B satisfies an inequality. This steel shows high creep strength on high-temp. long-time side and also has excellent toughness, workability, and weldability even if used as thick-walled material.;COPYRIGHT: (C)1997,JPO