Design for Novel Hot-Work Die Steel by Thermodynamic Calculation and Microstructural Examination

Metals

Minyu Ma¹  Yong Lian¹  Chao Zhao¹  Zhihao Yao²  Guoliang Xie³  Jinfeng Huang³  Jishan Zhang³  Zunjun Zhang³ 

[1] Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China;School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China;State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China;

关键词: alloy design;    hot-work die steel;    high-temperature strength;    nanocarbide;    thermodynamic calculation;   

DOI  :  10.3390/met9070805

来源: DOAJ

【 摘 要 】

In this paper, a new type of hot-work die steel with excellent high-temperature mechanical properties at 700 °C was designed based on the traditional 25Cr3Mo3NiNb steel with the help of Thermo-calc software. The effects of C, Cr, Mo, W and V on the types and mass fractions of carbides were studied. Phase diagram calculation revealed that with the increase of V and W contents and the decrease of Cr content, the precipitation temperature and the mass fraction of M₂₃C₆ carbides decreased. Meanwhile, the mass fraction of MC carbides increased as the Mo content decreased. Based on the thermodynamic calculation, new material 25Cr3Mo2NiWVNb steel was designed. Compared to the 25Cr3Mo3NiNb steel, more finely dispersed MC and M₂C carbides with high thermal stability, as well as fewer M₂₃C₆ carbides with low thermal stability, were precipitated in the new steel. The high-temperature tensile showed that the new steel showed high thermal stability and strength even at 700 °C. The high-temperature strengthening effect might be ascribed to the fine and stable nano-scale MC and M₂C carbides which precipitated during tempering.

【 授权许可】

Unknown