钼含量对4Cr5MoV热作模具钢冷热疲劳性能的影响  

Effect of Mo Content on Cold and Thermal Fatigue Properties of 4Cr5MoV Hot Work Die Steel

作　　者：邓俊杰 周健[2] 刘建雄[1] 迟宏宵[2] 林鹏[2] DENG Junjie;ZHOU Jian;LIU Jianxiong;CHI Hongxiao;LIN Peng(School of Materials Science and Engineering,Kunming University of Science and Technology,Kunming 650093,China;Special Steels Research Institute,Central Iron&Steel Research Institute,Beijing 100081,China)

机构地区：[1]昆明理工大学材料科学与工程学院,昆明650093 [2]钢铁研究总院特殊钢研究所,北京100081

出　　处：《机械工程材料》2022年第4期48-55,共8页Materials For Mechanical Engineering

摘　　要：采用室温至600℃的自约束冷热疲劳试验方法对含不同质量分数(1.8%,3.1%)钼的4Cr5MoV热作模具钢进行了试验,分析了表面与截面裂纹形貌、显微组织以及硬度变化,研究了钼含量对该热作模具钢冷热疲劳性能的影响。结果表明:经1 000次冷热疲劳循环后,含质量分数3.1%钼的试验钢表面产生细小稀疏裂纹,并且裂纹数量明显少于含质量分数1.8%钼的试验钢,含质量分数3.1%钼的试验钢具有更高的抗回火软化性,高的表面硬度可以延缓模具钢中冷热疲劳裂纹的萌生;经2 000次冷热疲劳循环后,含质量分数3.1%钼的试验钢截面裂纹扩展深度大于含质量分数1.8%钼的试验钢,其裂纹扩展速率较大,这与含质量分数3.1%钼的试验钢具有较低的室温冲击韧性和大量碳化物的粗化有关.The surface and section crack morphology, microstructure and hardness changes of 4 Cr5 MoV hot work die steel containing different mass fraction(1.8%, 3.2%) of Mo were analyzed by self-constrained cold and thermal fatigue test from room temperature to 600 ℃. The effect of Mo content on cold and thermal fatigue properties of hot work die steel was studied. The results show that after 1 000 cold and hot fatigue cycles, the cracks on the surface of test steel containing 3.1 wt% Mo were thin and sparse, and the crack number was significantly less than that of the test steel containing 1.8 wt% Mo;the test steel containing 3.1 wt% Mo had higher temper softening resistance, and high surface hardness could delay the initiation of cold and thermal fatigue cracks in the die steel. After 2 000 cold and thermal fatigue cycles, the crack propagation depth of the test steel containing 3.1 wt% Mo was greater than that of the test steel containing 1.8 wt% Mo, indicating the crack propagation rate was larger, which was related to the low impact toughness at room temperature and coarsening of a large amount of carbides of the test steel containing 3.1 wt% Mo.

关 键 词：4Cr5MoV热作模具钢 冷热疲劳裂纹 显微硬度 抗回火软化性 

分 类 号：TG11[金属学及工艺—物理冶金]