Wang Yilin, Geng Huicheng, Zhu Bin, Wang Zijian, Zhang Yisheng
State Key Lab of Materials Processing and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, China.
Materials (Basel). 2018 Nov 16;11(11):2302. doi: 10.3390/ma11112302.
The application of the quenching and partitioning (Q-P) process on advanced high-strength steels improves part ductility significantly with little decrease in strength. Moreover, the mechanical properties of high-strength steels can be further enhanced by the stepping-quenching-partitioning (S-Q-P) process. In this study, a two-stage quenching and partitioning (two-stage Q-P) process originating from the S-Q-P process of an advanced high-strength steel 30CrMnSi2Nb was analyzed by the simulation method, which consisted of two quenching processes and two partitioning processes. The carbon redistribution, interface migration, and phase transition during the two-stage Q-P process were investigated with different temperatures and partitioning times. The final microstructure of the material formed after the two-stage Q-P process was studied, as well as the volume fraction of the retained austenite. The simulation results indicate that a special microstructure can be obtained by appropriate parameters of the two-stage Q-P process. A mixed microstructure, characterized by alternating distribution of low carbon martensite laths, small-sized low-carbon martensite plates, retained austenite and high-carbon martensite plates, can be obtained. In addition, a peak value of the volume fraction of the stable retained austenite after the final quenching is obtained with proper partitioning time.
淬火分配（Q-P）工艺应用于先进高强度钢时，能显著提高零件的延展性，而强度降低很少。此外，高强度钢的力学性能可通过步进淬火分配（S-Q-P）工艺进一步提高。在本研究中，采用模拟方法分析了一种源自先进高强度钢30CrMnSi2Nb的S-Q-P工艺的两阶段淬火分配（两阶段Q-P）工艺，该工艺由两个淬火过程和两个分配过程组成。研究了不同温度和分配时间下两阶段Q-P过程中的碳再分布、界面迁移和相变。研究了两阶段Q-P过程后形成的材料的最终微观结构以及残余奥氏体的体积分数。模拟结果表明，通过两阶段Q-P工艺的适当参数可获得特殊的微观结构。可以获得一种混合微观结构，其特征是低碳马氏体板条、小尺寸低碳马氏体板、残余奥氏体和高碳马氏体板交替分布。此外，在适当的分配时间下，最终淬火后稳定残余奥氏体的体积分数会出现峰值。
