锻造加工对30CrNi2MoV钢在低温长时间回火下组织与性能的影响

Effect of Forging on Microstructure and Properties of 30CrNi2MoV Steel under Low Temperature and Long Time Tempering

采用拉伸试验、冲击试验、硬度测试、光学金相显微镜(OM)、扫描电子显微镜(SEM)等手段研究表征了在低温回火及延长回火时间条件下,锻造方式对30CrNi2MoV钢的微观组织与性能的影响。结果表明,经2次镦拔锻造工艺、再经1次镦粗或1次镦粗+1次拔长后,30CrNi2MoV钢的拉伸强度分别从1 070.1 MPa提升到1 215.4 MPa和1 189.8 MPa,冲击韧性显著提高,分别从39.67 J提高到85.33 J和84.67 J,其硬度也有一定程度的增强,从375HB分别增加到417.83HB和393.87HB。锻件的强度提高来源于材料内部晶粒的细化和均匀性,对材料进行后续锻造,其强化效果要明显高于只经过2次镦拔锻造工艺的效果。

The effect of forging method on the microstructure and properties of 30CrNi2MoV steel under low temperature tempering and long tempering time was studied by tensile test,impact test,hardness test,optical metallographic microscope(OM)and scanning electron microscopy(SEM).The results show that the tensile strength of 30CrNi2MoV steel is increased from 1 070.1 MPa to 1 215.4 MPa and 1 189.8 MPa respectively after upsetting again based on two times of upsetting and stretching forging process or the upsetting and stretching again based on two times upsetting and stretching forging process.The impact toughness is significantly improved from 39.67 J to 85.33 J and 84.67 J respectively.and the hardness was also enhanced to some extent,from 375 HB to 417.83 HB and 393.87 HB,respectively.The strength improvement of the forging is derived from the refinement and uniformity of the grain inside the material.It is found that the strengthening effect of the subsequent forging process on the material is obviously higher than two times of upsetting and stretching forging process.