| 摘要 |
PURPOSE:To obtain the titled high tensile steel plate with superior cold workability, etc. by hot rolling a low C-high Si-Mn-Cr-Ti steel at a specified heating temp. and a specified finish temp. and coiling the rolled plate at a prescribed temp. CONSTITUTION:A steel contg. 0.01-0.08% C, 0.5-2.0% Si, <=1.5% Mn, 0.2-0.6% Cr and 0.05-0.2% Ti is heated to >=1,150 deg.C and hot-rolled at 800-900 deg.C finish temp. to minimize the precipitation of Ti carbonitride not contributing to the strength during the hot rolling. The hot rolled steel plate is then coiled at 550- 700 deg.C coiling temp. to precipitate Ti carbonitride, etc. As a result, a high yield ratio and high ductility type nonrefined hot-rolled high-tensile steel plate with >=55kg/mm.<2> high strength, superior strength - notch elongation balance and >=80% high yield ratio is obtd. |
