| 摘要 |
<p>PURPOSE:To produce the steel plate with superior productivity by subjecting a steel, having a composition in which respective contents of C, Si, Mn, P, S, Al, N, Ti, and Nb are specified, to hot rolling, cooling, and coiling under respectively prescribed conditions and then exerting heating in a carburizing- atmosphere gas. CONSTITUTION:A steel having a composition consisting of, by weight, <=0.01% C, <=0.2% Si, <=0.05-1% Mn, <=0.1% P, <=0.02% S, 0.01-0.08% SolAl, 40.005% N, further specific amounts of Ti and/or Nb, and the balance Fe is refined. This steel is heated at 1000-1250 deg.C, and hot rolling is finished at a temp. between (Ar3-50) and 950 deg.C. Subsequently, the resulting plate is cooled within 2sec at >=10 deg.C/S cooling rate, and coiled at 400-800 deg.C. Then, this plate is pickled and heated in a carburizing-atmosphere gas, by which solid-solution C is provided by 10-30ppm.</p> |
