| 摘要 |
PURPOSE:To manufacture a steel plate with superior resistance to hydrogen embrittlement and stress corrosion cracking due to sulfide by heating and rolling a steel slab having a specified composition contg, C, Si, Mn, P, Al, Ti and Ni as basic components and by carrying out controlled cooling. CONSTITUTION:A steel slab consisting of 0.02-0.12% C, <=0.6% Si, 0.6-1.5% Mn, <=0.015% P, 0.01-0.10% Al, 0.005-0.025% Ti and 0.1-1.0% Ni as basic components, <=0.003% S, <=0.005% O, <=0.006% Ca and the balance Fe with inevitable impurities or further contg. a restricted amount of one or more among Cu, Cr, Nb, V and B and satisfying the equations is heated to 1,000-1,200 deg.C and rolled so as to regulate the draft at <=900 deg.C to >=60% and the finishing temp. to the Ar3 transformation point or above. After finishing the rolling, the rolled slab is cooled to 350-550 deg.C at 10-40 deg.C/sec cooling rate and allowed to cool. |
