轧制工艺对低碳中锰钢微观组织和力学行为的影响

Effect of Rolling Process on Microstructure and Mechanical Behavior of Low Carbon Medium Manganese Steel

目的研究热轧和温轧两种轧制工艺对低碳中锰钢的微观组织演变和力学性能的影响规律,阐明两种轧制工艺对马氏体转变和应变硬化行为的影响。方法通过对热轧和温轧两种轧制工艺得到的实验钢进行拉伸性能测试,分析温轧后实验钢强塑性同步提升的现象,通过EBSD数据分析,测量热轧和温轧实验钢中马氏体的转变量,并对两种轧制工艺拉伸后实验钢的断裂行为进行讨论。结果高温区轧制后,得到稳定性较差的粗大奥氏体组织,虽然其马氏体转变量较高,但是其伸长率和抗拉强度较低(抗拉强度为757.9 MPa,伸长率为13.1%);两相区温度进行中高温轧制后,可以得到多尺度、稳定性适中的奥氏体组织,显著提高材料的伸长率和抗拉强度(其抗拉强度为1313.2 MPa,伸长率为35.8%),获得较优的综合力学性能。结论通过合金成分优化设计,采用两相区轧制工艺,调整奥氏体稳定性,可以简化制备流程并获得高强塑性中锰钢。

This work aims to study the effects of hot rolling and warm rolling on the microstructure evolution and mechani-cal properties of low carbon medium manganese steel,and to clarify the influence of two manufacturing processes on martensite transformation and strain hardening behavior.By testing the tensile properties of experimental steel of the two manufacturing processes of hot rolling and warm rolling,the phenomenon of simultaneous increase in strength and plasticity of experimental steel after warm rolling was analyzed;through the EBSD data analysis,the amount of martensite transformation in hot-rolled and warm-rolled experimental steels was measured,and the fracture behavior of the experimental steels after two rolling proc-esses was discussed.The high temperature rolling method is used to obtain a coarse austenite structure with poor stability.Al-though its martensite transformation amount is high,its elongation and tensile strength are poor(tensile strength is 757.9 MPa,elongation is 13.1 %);while a multi-scale, moderately stable austenite structure can be obtained by two-phase zone rolling, theelongation and tensile strength of the material are significantly improved (the tensile strength is 1313.2 MPa, 35.8%), and thebetter comprehensive mechanical properties are obtained. By optimizing the composition of the alloy, adopting the two-phaserolling process and adjusting the austenite stability, the preparation process can be simplified and the medium manganese steelwith high strength and plasticity can be obtained.