本文系统地研究了钢中硅含量的变化(0.2～3.5％)对(WMo2Cr_4VSi钢二次硬化的影响,探讨了硅影响二次硬化的机理。结果和分析表明:硅可以降低二次硬化峰值温度10～70℃,提高二次硬度1～3HRC;其原因是硅降低了特殊碳化物在回火时的析出温度,细化了回火析出的特殊碳化物并增加其析出量。硅对钢的抗回火稳定性不利,但并不降低温度低子600℃时的红硬性, This paper systematically studied the effect of silicon content (0.2 ~ 3.5%) on the secondary hardening of WMo2Cr_4VSi steel and the mechanism of the effect of silicon on secondary hardening.Results and analysis show that silicon can reduce the secondary hardening peak temperature 10 ~ 70 ℃, improve the secondary hardness of 1 ~ 3HRC; The reason is that silicon reduces the precipitation temperature of special carbide during tempering, refine the special carbide precipitation and increase the amount of precipitation. Anti-tempering stability of the negative, but does not reduce the temperature low sub-600 ℃ red hardness,