Mo含量对D2钢组织与性能的影响

Effect of Molybdenum on Microstructure and Properties of AISI D2 Tool Steel

采用OM、SEM、TEM、XRD、EDS等分析手段,研究了Mo含量变化对D2钢组织和性能的影响规律。结果表明,随Mo含量增加,D2钢铸态组织晶粒细化,共晶碳化物数量增多,形态由细长棒状转变为条块状和鱼骨状。与棒状碳化物相比,鱼骨状和条块状碳化物热稳定性增强,加热过程中难以溶解和球化,导致淬火后基体中合金固溶度降低,回火后硬度下降。D2钢Mo含量最佳范围为0.9%~1.1%(质量分数),此时淬回火硬度可达61 HRC,冲击韧性20 J/cm^2以上,具有良好的综合使用性能。

Effect of Mo-content on the microstructure and properties of AISI D2 tool steel has been studied by means of OM, SEM, TEM, XRD and EDS. Results show that with the increasing Mo-content,the grain size of the steel decreased, while the amount of eutectic carbides increased, and the morphology of which changed from rod-like to fish bone-like and block-like. The thermal stability of the fish bonelike and block-like carbides is higher than that of the rod-like ones, thereby, they are difficult to dissolve and spheroidize during heating process. This fact may result in the decrease in solubility of alloying elements after quenching, and the decrease in hardness after tempering. The optimum Mo content is between 0.9% and 1.1%, correspondingly, the hardness of the tempered D2 steel is 61 HRC, and the impact toughness reaches about 20 J/cm^2.