等温淬火时间对D2钢组织与力学性能的影响

Effect of austempering time on microstructure and mechanical properties of D2 steel

研究了等温淬火时间对D2冷作模具钢微观组织与力学性能的影响。结果表明:随等温淬火时间延长,D2钢硬度先升高后降低,冲击韧性逐渐升高;应用Image pro-Plus6.0定量计算的下贝氏体含量逐渐增多,X-射线衍射仪(XRD)衍射图谱显示基体中含有残留奥氏体。其中,270℃等温淬火6 h时D2钢硬度与冲击韧性配合最佳,分别达到了61.1 HRC与56 J/cm^2,此时试样基体中下贝氏体含量为28.28%;M/B_下复相组织中残留奥氏体的碳含量较高,为1.345%,其室温稳定性较强,这更有利于冷作模具在服役过程中组织和精密尺寸的稳定。

Effect of austempering time on microstructure and mechanical properties of D2 cold working die steel was investigated.The results show that with the increase of austempering time,the hardness of the D2 steel first increases and then decreases,and the impact toughness increases gradually.The content of lower bainite calculated by Image pro-Plus6.0 increases,and the XRD diffraction pattern shows that there is retained austenite in the matrix.The hardness and impact toughness of the D2 steel are the best when austempering at 270℃for 6 h,and the hardness and the impact toughness are 61.1 HRC and 56 J·cm-2,respectively,and the lower bainite content in the matrix is 28.28%.The carbon content of retained austenite in the martensite/lower bainite multi-phase microstructure is 1.345%,which is more stable at room temperature,which is more favorable to the stability of microstructure and precision size of the D2 cold working die during service.