汽车用低碳热轧Q&P钢的组织性能测试及研究

Test and Research on Microstructure and Properties of Low Carbon Hot Rolled Q&P Steel for Automobile

摘要: 基于汽车轻量化原则，通过热轧后的超快冷与配分热处理技术得到了强韧性优异的980 MPa级热轧Q&P钢，研究了配分时间对其组织与性能的影响。研究表明：随着配分时间增加，钢中马氏体体积分数逐渐减少，抗拉强度由1016 MPa降低至938 MPa，伸长率由19.0%增加至24.5%，屈强比较低在0.6左右，n值较高为0.16~0.18，强塑积较高在20 GPa•%左右。当配分时间为30 s时，得到的残余奥氏体较多，其抗拉强度较高为987 MPa、伸长率为24.0%，但其屈强比最低、n值和强塑积最高，综合力学性能最好。

Abstract: Based on the principle of vehicle lightweight, 980 MPa hot-rolled Q&P steel with excellent strength and toughness was obtained through ultra fast cooling and partitioning heat treatment technology after hot rolling, and then effect of partitioning time on microstructure and mechanical properties of the tested steel was studied. The results show that with the partitioning time increases, the volume fraction of martensite in the steel gradually decreases, the tensile strength decreases from 1016 MPa to 938 MPa, the elongation increases from 19.0% to 24.5%, the yield ratio is low at around 0.6, the n value is high at 0.16~0.18, and the strength plasticity is high at around 20 GPa•%. When the partitioning time is 30 s, more residual austenite is obtained, with a higher tensile strength of 987 MPa and an elongation of 24.0%. However, its yield ratio is the lowest, n value and strength plastic product are the highest, and its comprehensive mechanical properties are the best.