摘要
借助OM、SEM、热膨胀仪以及力学性能试验,对比研究了两种含W、Mo的新型热作模具钢(HDLM钢和HDCM钢)在回火过程中组织与性能转变。结果表明:两种试验钢的马氏体相变临界冷速分别为8℃/s和9℃/s,1080℃真空油淬后两种钢的组织为板条状上贝氏体。经回火后,二者均具有非常明显的二次硬化效应,硬化峰值均出现在580℃,在此状态下合金碳化物的早期弥散析出极大地提升了两者的硬度。冲击性能试验结果表明:两种试验钢的韧性变化趋势存在明显差异,HDLM钢的冲击性能远远低于HDCM钢,这主要是由于VC沿晶偏聚粗化使HDLM钢的内应力集中。
Microstructure and mechanical property evolution during tempering process of two novel hot-work tool steels （ HDLM and HDCM） containing Mo and W were investigated by means of OM, SEM, thermal dilatometer and mechanical property tester. The experimental results demonstrate that the critical cooling rates of martensite phase transformation for these two tested steels are 8 ℃/s and 9 ℃/s respectively, both of their microstmcture are lath-like upper bainite when oil-quenched at 1080 ℃. These two tested steels exhibit very obvious secondary hardening effect during tempering process, and their peak hardness appears at 580 ℃ , at this temperature the early stage of alloying carbide dispersion precipitation improves the hardness greatly. Impact property test indicates that the toughness variation trends of these two tested steels are very different, the toughness of HDLM steel is far less than that of the HDCM steel, which is mainly due to that the coarsening of intergranular carbides causes the stress concentration in HDLM steel.
出处
《金属热处理》
CAS
CSCD
北大核心
2016年第5期12-18,共7页
Heat Treatment of Metals
关键词
热作模具钢
上贝氏体
二次硬化
碳化物析出
冲击性能
hot-work tool steel
upper bainite
secondary hardening
carbide precipitation
impact property
