采用示波冲击试验和高分辨透射电子显微分析技术，研究了回火冷却方式对正火１２Ｃｒ１ＭｏＶ钢回火脆化的影响。结果表明，该钢存在两个不同的回火冷速敏感性温度区间：高于６４０℃回火，铁素体基体中沉淀析出碳化物以ＶＣ类型为主，回火脆性没有明显的冷速敏感性；低于６４０℃回火，基体中沉淀析出的碳化物以Ｆｅ３Ｃ类型为主，回火脆化具有明显的冷速敏感性和可逆性。 The influence of tempering cooling on temper embrittlement of 12Cr1MoV steel was studied by using oscillometric impact test and high-resolution transmission electron microscopy. The results show that there are two different tempering cooling sensitivities in the steel. When the temperature is higher than 640 ℃, the carbide precipitated in the ferrite matrix is ​​dominated by VC type, and the temper brittleness has no obvious cooling sensitivity ; Less than 640 ℃ tempering, precipitated carbide matrix Fe3C type-based, temper embrittlement has a clear cold sensitivity and reversibility.