退火温度对热轧中锰钢组织性能的影响

Effect of Annealing Temperature on Microstructure and Mechanical Properties of Hot-Rolled Medium Manganese Steel

摘要: 基于汽车轻量化原则，通过两阶段控制轧制和两相区退火热处理技术得到了强韧性优异的800 MPa级热轧中锰钢，研究了退火温度对其组织与性能的影响。研究表明：随着退火温度增加，钢中奥氏体体积分数先增加后减少，抗拉强度先减少后增加，屈服强度由694 MPa减少到492 MPa，伸长率先增加后减少在21.0%~31.5%，强塑积先增加后减少。当退火温度为640℃时，得到的奥氏体最多为21.3%，其抗拉强度为796 MPa、屈服强度为570 MPa，伸长率为31.5%，强塑积为25.1 GPa·%，综合力学性能最好。

Abstract: Based on the principle of vehicle lightweight, 800 MPa hot-rolled medium manganese steel with excellent strength and toughness was obtained through two-stage controlled rolling process and dual-phase heat treatment technique, and effect of annealing temperature on its microstructure and mechanical properties was studied. The results show that with the annealing temperature increases, the volume fraction of austenite in steel first increases and then decreases, while the tensile strength first decreases and then increases. The yield strength decreases from 694 MPa to 492 MPa, and the elongation rate first increases and then decreases within the range of 21.0% to 31.5%. The strength-ductility product first increases and then decreases. When the annealing temperature is 640˚C, the maximum austenite obtained is 21.3%, the tensile strength, yield strength, elongation, strength-ductility product of the tested steel are 796 MPa, 570 MPa, 31.5%, 25.1 GPa·%, respectively, and shows the best comprehensive property.