Effect of Silicon on Thermal Stability of 4Cr3Mo2V Hot-Work Die Steel

Thermal stability is one of the most basic high-temperature performance indices hot die steel. It directly determines whether mold can maintain good surface hardness, dimensional and material failure resistance for a long time under high temperature pressure, then affect service life material. In this paper, effect Si on thermal 4Cr3Mo2V hot-work steel was studied. Scanning electron microscopy (SEM) transmission (TEM) techniques were used to characterize microstructure evolution. Thermodynamic analyses carried out in combination with Thermo-Calc software explore mechanism affecting stability. The results show that 1.0% Si-containing (referred as 1.0 steel) sample exceeded 0.3% 0.3 sample. After tempering at 650 °C 64 h, matrices two tested samples mainly comprised large-sized M6C carbides. Additionally, carbides showed obvious aggregation growth, small number round-like M23C6 appeared, which decreased hardness later stage tempering. average particle size 100–200 nm, 100–400 disperses precipitates finer MC-type M2C-type secondary carbides, so it has better