FIRE-RESISTANT STEEL EXCELLENT IN HIGH-TEMPERATURE STRENGTH, TOUGHNESS AND REHEAT EMBRITTLEMENT RESISTANCE AND PRODUCTION PROCESS FOR THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a fire-resistant steel excellent in high-temperature strength, toughness and reheat embrittlement resistance, and to provide a production process for the same.;SOLUTION: A fire-resistant steel contains 0.001 to 0.030% C, 0.05 to 0.50% Si, 0.4 to 2.0% Mn, 0.03 to 0.50% Nb, 0.005 to less than 0.040% Ti, 0.0001 to less than 0.0050% N and 0.005 to 0.030% Al, further one or more elements selected from 1.5% or less Cr, 1.0% or less Cu and 1.0% or less Ni, and P and S limited to 0.03% or less and 0.02% or less respectively, while controlling the contents of C, Nb, Ti and N so as to satisfy the relationships C-Nb/7.74≤0.005 and 2≤Ti/N≤12. The production process includes heating a steel slab to 1,100 to 1,350°C and hot-rolling the steel slab with a cumulative rolling reduction of 30% or more at 1,000°C or lower.;COPYRIGHT: (C)2008,JPO&INPIT