ORTHOGONAL TEST OF OPTIMUM STRENGTH AND TOUGHNESS OF CONTINUOUS CASTING Ni-Cr-Mo-V STEEL

Heat treatment technology parameters of continuous casting Ni-Cr-Mo-V steel with optimum strength and toughness were obtained through orthogonal test of 4 factors,3 levels and 9 experiments.It is presented that the cooling speed and tempering temperature are the main factors to improve strength and toughness of steel.Believed degree is 95%~99%.Quenching temperature and tempering time are less important factors.The best technological parameters are cooling speed 4.4℃ s,quenching temperature 620℃,tempering temperature 680℃,tempering time 40min, σ_s=571.6MPa and A_kv(-40℃)=192J.