Abstract: The effects of hot-rolled three-stage cooling and temper-rolling processes on mechanical properties of 2.3 mm 700 MPa grade Nb-Ti micro-alloying S600MC high strength steel strip (/% : 0.07C, 0.15Si, 1.50Mn, 0.015P, 0.003S, 0.025Alt, 0.015Nb, 0.08Ti) are studied. When end rolling at 870 as intermediate temperature decreasing from 670 X. to 580 °C , the yield strength increases from 577 MPa to 600 MPa, the tensile strength basically remaines unchanged (774 MPa to 784 MPa) , the elongation decreases from 24% to 21% , and the yield ratio increases by 0.04. When the coiling temperature increases from 150 °C to 250 °C , the mechanical properties remain unchanged. The yield strength of high strength steel with primary temper-rolling process increases by 20 MPa to 43 MPa, while the tensile strength changes slightly and the elongation decreases by 2-5 percentage point. The yield strength increases by the secondary temper-rolling process significantly to 101 MPa, while the elongation decreases by 8 percentage point, which is adverse to comprehensive properties.

Key words: S600MC High Strength Steel, Three-Stage Cooling Process, Temper-Rolling Process, Mechanical Properties

摘要： 研究了热轧后三段冷却工艺和平整工艺对2.3 mm 700 MPa级S600MC高强钢板(/%:0.07C, 0.15Si, 1.50Mn, 0.015P, 0.003S, 0.025Alt, 0.015Nb, 0.08Ti)力学性能的影响。终轧温度870℃,采用三段冷却工艺，中间温度由670℃降至580℃时，屈服强度由557 MPa提高至600 MPa,而抗拉强度基本保持不变(774 MPa至786 MPa),伸长率由24%降至21%,屈强比提高0.04。卷取温度由150℃提高至250℃时，力学性能基本保持不变。一次平整工艺提高高强钢屈服强度达到22～43 MPa,而抗拉强度变化不大，伸长率下降2～5个百分点。二次平整工艺对屈服强度提升尤为明显，可以达到101 MPa,但伸长率下降达到8个百分点，反而不利于改善综合性能。

关键词: S600MC高强钢, 三段冷却工艺, 平整, 力学性能