Effect of V Element and Heat Treatment Process on Microstructure and Properties of High Carban Microalloyed Steel

In order to improve the conditional fracture toughness value of V microalloyed steel, the variation of precipitation phase with temperature of steels with 0.60% carbon content and different V element contents were analyzed by Thermo-Cale thermodynamic software, and the suitable V element content was determined. Through thermodynamic calculation and austenite grain size test, the stepped heat treatment process was proposed and the process effect was verified by high temperature metallographic thermal simulation test and laboratory muffle furnace. The results show that the stepped heat treatment process promoted the formation of ferrite without significantly reducing the hardness of steel, which made the strength and toughness both reached the predetermined targets, and the toughness coordination relationship of V microalloyed steel was obviously improved.