配分过程对热轧直接淬火配分钢拉伸性能及冲击韧性的影响

Effect of partitioning procedure on tensile properties and Charpy impact toughness of a hot-rolled directly quenched and partitioned steel

基于一种低碳硅锰系成分,结合热轧直接淬火配分工艺,开发了一种厚规格热轧直接淬火配分钢,研究了配分过程对实验钢微观组织,力学性能和冲击韧性的影响.用SEM、XRD、TEM分析观察材料的微观组织.研究结果显示,实验钢抗拉强度为1 080~1 400 MPa,屈强比为0.6~0.79,强塑积高达28 000 MPa%.等温配分钢的低温冲击韧性较动态配分钢更好,并且随着冲击温度的降低,等温配分钢冲击功比动态配分钢下降更慢.实验钢残余奥氏体含量（体积分数）为16%-28%,碳质量分数为1.05%-1.35%.同时等温配分钢较动态配分钢具有更高的残余奥氏体含量和更低的残余奥氏体碳含量.

Based onalow-C SiM n- type steel,a thick hot- rolled direct quenched and partitioned（HDQP） steel was developed combined with the Thermal Mechanical Control Processing（TMCP） technology.Effects of partitioning procedure on the micro structure,tensile properties and Charpy impact toughness of the steel were investigated.Microstructures of the steel were characterized by SEM,XRD and TEM.The results showed that the tensile strength of the specimens is between 1 080 MPa and 1 400 MPa,the yield ratio is about 0.6 ~ 0.79 and the product of strength and elongation can be up to 28 000 MPa%.The isothermally partitioned specimens exhibit better low temperature impact toughness and the impact toughness decreases much in the isothermally partitioned specimens compared with the dynamically partitioned specimen with decrease of the test temperature.The volume fraction of residual austenite is about 16%-28%,and the average carbon content（volume fraction） in residual austenite is about1.05%~ 1.35%.Meanwhile,the isothermally partitioned specimens possess much more residual austenite and much lower carbon of residual austenite compared with the dynamically partitioned specimen.