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采用Gleeble-3500热模拟试验机测定了不同温度下中锰钢的变形抗力,并通过分阶段拉伸、扫描电镜、电子背散射衍射、X射线衍射等实验手段,对温轧中锰钢中逆转变奥氏体的相变行为进行观察和分析。研究发现,热轧马氏体中锰钢经过600℃温轧及退火后,获得较多较稳定的残余奥氏体,从而实现强度859 MPa和延伸率36%的优良力学性能。拉伸变形前期,锯齿状流变应力现象明显,残余奥氏体提供持续的TRIP效应来提高塑性,此过程中尺寸较大的逆转变奥氏体稳定性差,变形时先发生转变;拉伸变形后期,锯齿状波动消失,超细晶铁素体和马氏体发生塑性变形,马氏体强化及铁素体中的位错强化为主要强化方式。
The deformation resistance of medium manganese steel at different temperatures was measured by Gleeble-3500 thermal simulation testing machine. By means of staged stretching, scanning electron microscopy, electron backscatter diffraction and X-ray diffraction, Change the behavior of austenite phase transition were observed and analyzed. The results show that after hot rolling and annealing at 600 ℃, the martensite in hot-rolled martensitic steel gets more and more stable retained austenite to achieve the excellent mechanical properties of 859 MPa in strength and 36% in elongation. In the early stage of tensile deformation, the zigzag flow stress phenomenon is obvious. The retained austenite provides continuous TRIP effect to improve the ductility. In this process, the larger reverse-transformed austenite has poor stability and first changes during deformation. Tensile deformation In the later period, the zigzag disappeared and the superfine-grained ferrite and martensite plastically deform, and the martensite strengthening and dislocation strengthening in ferrite were the main strengthening methods.