淬火冷速对51CrV4钢显微组织和力学性能的影响

Effect of quenching cooling rate on microstructure and mechanical properties of 51CrV4 steel

采用油、HX-2000以及不同浓度PAG对51CrV4钢进行淬火冷却,借助光学显微镜、扫描电镜(SEM)、电子背散射衍射(EBSD)技术、拉伸实验和洛氏硬度计等研究了不同淬火冷速对51CrV4钢显微组织和力学性能的影响。结果表明:提高淬火冷速对马氏体板条有明显细化效果,51CrV4钢的强塑积随着淬火冷速的提高呈先增后减的趋势。当使用13%PAG淬火及400℃回火保温100 min后,51CrV4钢的综合力学性能最佳:屈服强度和抗拉强度分别为1317.26和1560.89 MPa,断后伸长率和断面收缩率分别为10.50%和55.38%,硬度为47.4 HRC,强塑积达到16.39 GPa%。

51CrV4 steel was quenched by oil,HX-2000 and PAG with different concentrations.The effect of quenching cooling rate on microstructure and mechanical properties of the 51CrV4 steel was studied by means of optical microscope,scanning electron microscopy(SEM),electron backscatter diffraction(EBSD)technique,tensile experiments and Rockwell hardness tester.The results show that increasing quenching cooling rate has obvious refining effect on martensitic laths,and the product of strength and plasticity of the 51CrV4 steel increases first and then decreases with the increase of quenching cooling rate.After using 13% PAG quenching and then tempering at 400℃ for 100 min,the comprehensive mechanical properties of the 51CrV4 steel are the best:the yield strength and tensile strength are 1317.26 and 1560.89 MPa,respectively,the elongation and reduction of area are 10.50% and 55.38%,respectively,the hardness is 47.4 HRC,and the product of strength and plasticity reaches 16.39 GPa%.