ABSTRACT

In this paper, two kinds of cold-rolled 3.5Mn steels with different initial microstructures are designed. Combined with EBSD and dilatometer, the effect of Mn pre-partition on the austenite reversion and the mechanical properties in the subsequent intercritical annealing process are compared. The results show that the Mn pre-partition can significantly increase the austenite reversion rate, achieve a large amount of austenite formed in a short time isothermal process, and provide a sustained TRIP effect for the material during the tensile process. In the end, the specimen of HR700CR710 achieved excellent mechanical properties with yield strength of 1034 MPa, tensile strength of 1146 MPa, total elongation of 28.7%, and the product of strength and elongation of 32.9 GPa %.

摘要

本文设计了两种具有不同初始显微组织的冷轧 3.5Mn 钢。结合EBSD和膨胀仪，比较了Mn预分配对奥氏体回复的影响以及后续临界间退火过程中的力学性能。结果表明，Mn预分配能显着提高奥氏体回复率，实现在短时间内等温过程中大量奥氏体形成，为材料在拉伸过程中提供持续的TRIP效应。最终，HR700CR710试样取得了优异的力学性能，屈服强度为1034 MPa，抗拉强度为1146 MPa，总伸长率为28.7%，强度与伸长率之积为32.9 GPa %。