| 摘要 |
PURPOSE:To manufacture a hot-rolled high-tension steel plate having high strength and cold workability comparable to those of a conventional high Si and high Mn steel plate by rolling a low Si and low Mn steel billet at a low temp. and coiling the resulting plate at a specified temp. CONSTITUTION:A cast steel billet contg. 0.02-0.25% C, <0.14% Si, <0.02- 0.28% Mn, <0.025% P, <0.005% S and 0.01-0.10% sol. Al is manufactured. The billet may further contain one or more among at least one among <0.05% each of Nb, V and Ti (i), <0.0100% Ca (ii) and <0.0050% B (iii). The billet is hot rolled to a plate, and the hot rolling is finished at Ar3+50 deg.C-650 deg.C. The plate is rapidly cooled at >=50 deg.C/sec cooling rate and coiled at <=450 deg.C. A hot- rolled high-tension steel plate having superior strength and cold workability is obtd. while using said small amounts of added elements such as Si and Mn. |
