不同初始组织中锰钢逆相变退火后的室温组织与性能

Room temperature microstructure and properties of medium Mn steel with different primal microstructure after reverted transformation annealing

研究了0.1C-5Mn中锰钢两种初始组织形态(热轧淬火态与冷轧形变态马氏体)经两相区退火处理后的室温组织形貌及力学性能。结果表明:经退火处理后,热轧马氏体复相组织(铁素体+奥氏体)大部分保持板条状,而冷轧马氏体发生回复再结晶,形成多边形或等轴状(粒状)超细晶粒;冷轧退火样中残留奥氏体含量及其中C含量高于热轧退火样,表明冷轧初始组织形态有利于逆相奥氏体稳定及C元素配分;冷轧退火样的强度(屈服、抗拉)均高于热轧退火样,而断后伸长率稍低于热轧退火样,并且冷轧退火样加工硬化速率优于热轧退火样,两者强塑积均超过30 GPa·%,冷轧退火样强塑积偏高。

Room temperature microstructure and properties of 0.1C-5Mn (mass%)steel with two primal microstructures (hot-rolled quenched martensite and cold-rolled deformed martensite)after reverted transformation annealing were studied.The results show that after annealing,the multiphase microstructure of hot rolled martensite (ferrite and austenite)remains in the shape of strip,while the cold rolled martensite recrystallizes,forming polygonal or equiaxed (granular)ultrafine grains.The content of retained austenite and carbon in the cold rolled annealed sample is higher than that in the hot rolled annealed sample,which indicates that the primal microstructure of the cold rolled is beneficial to the stability of reversed austenite and carbon partitioning.The tensile and yield strength of the cold rolled annealed sample are better than that of the hot rolled annealed sample,but the elongation after fracture is slightly lower than that of the hot-rolled annealed samples,and the working-hardening rate of the cold-rolled annealed samples is better than that of the hot-rolled annealed samples.The PSE (product of strength and elongation)of the both samples is more than 30 GPa.%,and the cold-rolled annealed sample has a higher PSE.