首钢热轧DP580双相钢的工业试生产

采用合金成本低廉的C-Mn-Cr化学成分设计,通过层流冷却段的水冷—空冷—水冷的三段式冷却模式和低温卷取,成功在1 580mm机组上试生产580MPa级热轧双相钢。对试生产钢卷进行了性能均匀性分析,结果表明:除去轧钢头部弱冷区域,整卷性能均匀,马氏体比例可稳定在10%左右。进而得出当前采用的恒速轧制方法有利于热轧双相钢力学性能均匀性控制的结论。试生产中在终轧后实施了2种不同的中间温度,轧制结果显示2种工艺方案下屈服强度和屈强比差距较大。

Trial-Production of Hot Rolled DP580 Dual Phase Steel at Shousteel

The hot-rolled dual phase(DP) steels with tensile strength up to 580MPa were successfully trial-produced in 1580mm rolling mill in the ways that chemical compositions (C-Mn-Cr) were designed at a low cost, a three-step cooling (water cooling-air cooling-water cooling)and coiling at a low temperature were adopted. The results of the studies on mechanical properties at different positions of coil show that the mechanical properties of the whole coil are uniform, and the DP steels comprise microstructure of approximate 10% martensite in ferrite matrix apart from the head zone of coil in the case of weak cooling. Therefore, it can be confirmed that rolling at constant speed is conducive to uniformity control of the mechanical properties of hot rolled DP steels. Further more, the intermediate temperature after finished rolling plays an important role in yield strength and ratio of yield strength and tensile strength.