| 摘要 |
PURPOSE:To obtain a steel pipe for a boiler having superior bendability in a temp. range in which blue brittleness is shown by forming a steel having a restricted composition contg. C, Si, Mn, etc. into a pipe and by normalizing the whole steel pipe under specified conditions. CONSTITUTION:A steel consisting of 0.16-0.25% C, 0.14-0.30% Si, 1.00-1.50% Mn, <=0.025% P, <=0.010% S, 0.02-0.05% Cu, 0.01-0.05% Mo, 0.01-0.05% V, <=0.008% T.Al, <=0.0060% N and the balance Fe with inevitable impurities or further contg. 0.010-0.020% Ti is refined and formed into a pipe for a boiler. The whole steel pipe is normalized at Ac3+20 deg.C-Ac3+60 deg.C. By this method a steel pipe for a boiler having superior bendability in a temp. range in which blue brittleness is shown in obtd. without modification of the processing method. |
