| 摘要 |
<p>PURPOSE: A method for manufacturing high-strength hot-rolled DP steel with a tensile strength of about 590MPa and low property deviation is provided to reduce property deviation in the width and length directions of a strip and exclude a re-heating process by employing a thin slab continuous casting method. CONSTITUTION: A method for manufacturing high-strength hot-rolled DP steel comprises the steps of: continuously casting steel into a thin slab(a) 30-150mm thick, and successively roughing, heating, finish rolling, cooling, and coiling the thin slab. In the finish rolling step, rolling speed deviation in a single strip(b) is controlled to 15% or less. In the coiling step, the cooled strip is coiled at±30°C of a target temperature. The steel comprises C of 0.03-0.1weight%, Si of 0.01-1.1weight%, Mn of 0.8-2.0weight%, P of 0.001-0.1weight%, S of 0.001-0.02weight%, Al of 0.01-1.0weight%, N of 0.001-0,02 weight%, and total tramp element of 0.18weight% or less.</p> |
