淬火温度对中合金马氏体耐磨铸钢组织和性能的影响

Effect of quenching temperature on microstructure and mechanical properties of a medium alloy martensitic wear-resistant cast steel

对自行设计的矿山球磨机衬板用中合金马氏体耐磨铸钢在900、950、1000、1050、1100℃淬火后回火,研究了淬火温度对试验钢组织和性能的影响。试验结果表明,经过淬火、回火处理后的试验钢显微组织由板条马氏体和残留奥氏体组成。当保持回火温度250℃不变,随着淬火温度的升高,马氏体组织先变细密后又变粗大,抗拉强度、冲击性能及残留奥氏体含量均呈现先增大后减小的趋势,在1050℃淬火取得最优综合力学性能:抗拉强度1623 MPa,冲击性能14.4 J,此时试验钢的强化机理为孪晶马氏体和高密度位错缠结。通过冲击磨损试验解释了试验钢在该工艺下的磨损行为与磨损机理。

A self-designed medium alloy martensitic wear-resistant cast steel was quenched at 900,950,1000,1050,1100℃then tempered respectively,and the influence of quenching temperature on microstructure and mechanical properties of the tested steel was studied.The results indicate that the microstructure of the tested steel after quenching and tempering is composed of lath martensite and retained austenite.When the tempering temperature is kept constant at 250℃,with the increase of quenching temperature,the martensite structure first becomes finer and then coarser,and the tensile strength,impact properties and residual austenite content increase first and then decrease.The tested steel achieves the best comprehensive mechanical properties at 1050℃:tensile strength of 1623 MPa,impact property value of 14.4 J,the corresponding strengthening mechanism is twin martensite and high-density dislocation entanglement.And the wear behavior and the wear mechanism of the tested steel under this process are explained by the impact wear test.