回火温度对4Cr5MoSiV1Ti钢组织性能的影响

Effect of Tempering Temperature on Microstructure and Properties of 4Cr5MoSiV1Ti Steel

采用真空感应炉熔炼新型4Cr5MoSiV1Ti热作模具钢,研究了回火温度对其力学性能、断口形貌及显微组织的影响。结果表明:随回火温度升高,4Cr5MoSiV1Ti钢的抗拉强度先上升后降低,回火温度为520℃时,抗拉强度最高,伸长率和断面收缩率先略有减小后大幅增加;4Cr5MoSiV1Ti钢拉伸断口均为解理刻面断裂,但随回火温度升高,断面从与拉伸轴垂直的方向转变为与拉伸轴呈45°夹角,且等轴状和抛物线状韧窝逐渐增加,同时碳化物的析出数量增多、尺寸增大。

The new 4Cr5MoSiV1Ti hot work die steel was smelted using a vacuum induction furnace,the effect of tempering temperatures on its mechanical properties,fracture morphology and microstructure was studied.The results show that with the increase of tempering temperature,the tensile strength of 4Cr5MoSiV1Ti steel increased first and then decreased,when the tempering temperature was 520℃,the tensile strength was the highest,and the elongation and reduction of area decreased slightly at first and then increased substantially.The tensile fractures of 4Cr5MoSiV1Ti steel were all cleavage facet fractures,but with the increase of tempering temperature,the section gradually changed from a direction perpendicular to the tensile axis to a direction at an angle of 45°to the tensile axis,and the equiaxed and parabolic dimples gradually increased.Meanwhile,the number and size of secondphase carbides precipitated in the steel gradually increased.