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对30CrMnSiA钢高温回火脆性进行了研究。结果表明：30CrMnSiA钢经650℃回火保温后缓冷或500℃等温时，冲击韧性值降低。下降的程度随等温时间的延长而加剧；下降的速度随时间的延长而减慢。经不同时间等温脆化后再经650℃保温1h水冷的脱脆处理，冲击韧性全部恢复，与预先的脆化程度无关。在公认的高温回火脆性温度范围以下380℃保温，同样产生脆化。无论是脆化处理还是初化处理和脱脆处理的冲击试样，当断口上出现沿晶断裂区时，其沿晶面上均存在有大量的质点和小孔洞。作者认为，高温回火脆性主要因置换型团溶杂质原子（P、Sb、Sn、As等）与间隙型团溶原子（C、N）一起在位错线上形成柯氏气团所致。而奥氏体化时沿晶界析出的第二相质点，虽然弱化了晶界，但不是产生脆化的主要原因。
The high temperature temper brittleness of 30CrMnSiA steel was studied. The results show that the impact toughness of 30CrMnSiA steel after being tempered at 650 ℃ is slow cooling or isothermal at 500 ℃. The degree of decline intensified with isothermal time; the rate of decline slowed with time. After isothermal embrittlement at different times and then 650 ℃ heat insulation 1h water-cooled de-embankment treatment, all of the impact toughness recovery, and has nothing to do with the degree of pre-embrittlement. In the recognized high temperature temper brittleness temperature below 380 ℃ insulation, the same embrittlement. Whether it is embrittlement treatment or impact treatment of initial treatment and de-embrittlement treatment, when the intergranular fracture zone appears on the fracture surface, a large number of particles and small holes exist along the crystal plane. The authors believe that the high temperature temper brittleness is mainly caused by the formation of Koch’s gas clusters on the dislocation line due to the substitutional cluster-like impurity atoms (P, Sb, Sn, As, etc.) together with the interstitial cluster atoms (C, N). However, the second phase particles precipitated along the grain boundaries during austenite weakening the grain boundaries are not the main causes of embrittlement.