STEEL MATERIAL HAVING SUPERIOR RESISTANCE TO CRACKING DUE TO HYDROGEN EMBRITTLEMENT IN HYDROGEN SULFIDE ENVIRONMENT

摘要

PURPOSE:To obtain a steel material having improved resistance to cracking due to hydrogen embrittlement and stress corrosion cracking at its weld heat-affected zone in environment contg. hydrogen sulfide by providing a specified composition consisting of C, Si, Mn, P, S, Al, Nb, Ti, V and Fe, and restricting the amount of residual carbon. CONSTITUTION:A steel material having superior sulfide corrosion cracking resistance is obtd. by providing a composition consisting of =0.08% C, 0.01-0.50% Si, 0.8-2.5% Mn, =0.025% P, =0.004% S, 0.005-0.1% Al, one or more among =0.12% Nb, =0.15% Ti and =0.15% V, and the balance Fe with inevitable impurities and by restricting the amount of residual carbon (C) represented by the equation to 0.005-0.03%. To the composition may be added one or more among =0.007% Ca, =0.007% Mg and =0.1% REM, and/or one or more among =1.0% Cu, =1.0% Cr, =1.0% Mo, =1.0% Ni, =0.2% Zr and =0.003% B.