合金元素Mn、Cr对SWRCH45K钢组织和性能的影响

Effect of alloy elements Mn and Cr on microstructure and properties of SWRCH45K steel

研究了Mn、Cr含量对SWRCH45K钢组织和性能的影响。试验钢的淬火温度为860℃,分别进行油冷和水冷,同时利用模拟软件对淬火后硬度进行模拟计算。试验结果表明,Mn、Cr含量提高导致试验钢的抗拉强度有所增加;油冷试验钢组织均为铁素体+屈氏体,心部组织中铁素体比例略高;水冷试验钢近表面处组织为马氏体+少量的屈氏体,心部组织中屈氏体随Mn、Cr含量增加而减少。油冷试验钢硬度沿直径方向上的变化较小,0.70%Mn-0.04%Cr试验钢硬度在22~24 HRC之间,且明显低于其它试验钢;水冷试验钢近表面处硬度差异较小,心部硬度下降明显。试验结果与模拟结果对比表明,试验钢近表面处硬度值与模拟结果具有较好相符性。

Effect of Mn and Cr content on the microstructure and properties of SWRCH45 K steel was studied.The steel was quenched by heating at 860 ℃ + oil or water cooling,in addition,the hardness after quenching was simulated by using simulation software.The results show that with the increase of Mn and Cr content,the tensile strength of the tested steel is increased.The oil quenching microstructure of the tested steel consists of ferrite + troostite,with the ferrite fraction is slightly higher in the core of the specimen.The water quenching microstructure near the surface of the tested steel consists of martensite + a little troostite,while the troostite in the core of the specimen decreases with the increase of Mn and Cr content.The hardness of the tested steel after oil quenching changes slightly along the diameter direction,and the tested steel specimens with 0.70% Mn-0.04% Cr have the lowest hardness which is within 22-24 HRC and markedly lower than that of other specimens.The near-surface hardness difference among the water quenched specimens is relatively small,while the core hardness decreases obviously.It is found from comparison that the simulation hardness values are in good agreement with the near-surface hardness of the quenching specimens.