为获得风力发电机主轴用34CrNiMo6合金结构钢的韧脆转变温度,沿其径向不同位置处制取V型冲击试样,并在-110~25 ℃进行了夏比冲击试验,利用Boltzman函数对剪切断面率与温度进行拟合,得到韧脆转变温度曲线并获得脆性断面占50%所对应的试验温度(即FATT50).利用扫描电镜分别观察试样脆性及韧性断口形貌,简要分析了该材料在脆性及韧性条件下的断裂行为.试验结果表明：该主轴用34CrNiMo6钢的韧脆转变温度在-50~-70 ℃,且主轴表面的韧脆转变温度比芯部的稍低.较高试验温度下试样塑性断口表现出典型的韧窝状形貌,随着试验温度的降低,逐渐向解理形貌过渡.

In order to obtain the ductile-brittle transition temperature of 34CrNiMo6 steel used for wind turbine spindle, V-type impact samples were taken at different radial positions, they were tested between -110 ℃ and 25 ℃,the result data was fitted by Boltzman function,then the temperature at 50% of the brittle fracture (FATT50) was obtained from the ductile-brittle transition temperature curve.The brittle and ductile fracture morphology of samples was observed by SEM, the brittle and plastic fracture behaviors of 34CrNiMo6 alloy were briefly analyzed.The results indicated that the ductile-brittle transition temperature of 34CrNiMo6 alloy was between -50 ℃ and -70 ℃, and the transition temperature of spindle surface was lower than that at its core position.Plastic fracture samples showed a typical dimple-like morphology, the fracture surface morphology gradually transited to cleavage fracture as the test temperature decreased.