Thermodynamic Calculation and Analysis of Equilibrium Precipitated Phases in ZG1Cr10MoWVNbN Heat-Resistant Steel

The equilibrium phases existing in ZG1Cr10MoWVNbN heat-resistant steel between 400 ℃ and 1 600 ℃ were calculated by Thermo-Calc software, and the effects of alloy elements of Mo, W, Nb, V on major precipitated phases were studied. The results show that the matrix of heat-resistant steel after quenching at 1 200 ℃ was single martensite when the content of carbon was 0.11wt%. The main equilibrium precipitated phases were MX, M23C6 and Laves, which corresponded to the precipitation temperature of 1 190 ℃, 880 ℃ and 780 ℃ respectively. The MX phase rich in Nb precipitated firstly, then those rich in V. M6C which was harmful to the steel, precipitated when the content of alloy element Mo was more than 1.5wt%. W could accelerate the precipitation of Laves phase, consequently strengthened the steel.