一步QP处理低碳中锰钢的微观组织和力学性能

Microstructure and Mechanical Properties of Low Carbon Medium Mn Steel Treated by One-step Quenching and Paititioning Process

对低碳中锰钢进行了一步QP工艺处理,获得了铁素体、回火马氏体、新生马氏体和残余奥氏体的混合组织,采用SEM、XRD和拉伸试验机研究了配分时间对试验钢的显微组织和力学性能的影响。结果表明:抗拉强度和伸长率都是随着配分时间的延长先升高后降低。试验钢的抗拉强度主要受回火马氏体的回火程度和新生马氏体的数量以及碳含量共同影响,配分20 min时达到最佳平衡状态,试验钢的抗拉强度达到最高,为1712 MPa。试验钢的伸长率主要由残余奥氏体的含量决定,配分20 min时残余奥氏体含量最高,获得最大伸长率9.8%。

The mixed structure of ferrite,tempered martensite,fresh martensite and retained austenite of low carbon medium Mn steel was obtained by one-step QP heat treatment.The effects of partition time on the microstructure and mechanical properties of test steel were studied by means of SEM,XRD and tensile tester.The results show that,the tensile strength and elongation increase first and then decrease with the increase of partition time.The tensile strength of test steel is mainly affected by tempering degree of tempered martensite,quantity of new martensite and carbon content.The optimum equilibrium state is achieved when 20 min partition is used,and the tensile strength of the test steel is the highest,which is 1712 MPa.The elongation of the test steel is mainly determined by the content of residual austenite,and the content of residual austenite is the highest with 20 min partition,and the maximum elongation is 9.8%.