为研究拟合函数对燃气轮机轮盘韧脆转变温度评定结果的影响，在不同温度下对燃气轮机轮盘进行夏比冲击试验，分别采用线性内插、玻尔兹曼函数、双曲正切函数的冲击吸收能量和脆性断面率进行拟合，计算得到相应的特定比例断口形貌转变温度F_{ATT SEPC}和特定冲击吸收能量转变温度E_{TT AV}，并对计算结果进行了比较与分析。结果表明：对于钢铁材料，无论是断口形貌还是冲击吸收能量的转变温度，通过合理设定边界值，采用双曲正切函数和玻尔兹曼函数可获得近似一致的拟合结果。而双曲正切函数的物理意义更明确，且对一些非对称转变曲线的拟合更具优势，线性内插拟合只能粗略预估转变温度是否合格，当其接近要求值时，不能用于判定是否合格，还需采用玻尔兹曼函数或双曲正切函数进行精确拟合。

In order to study the effect of different fitting functions on the evaluation results of ductile brittle transition temperature of gas turbine disk, the charpy impact tests of gas turbine disk were carried out at different temperatures, the linear interpolation, Boltzmann function and hyperbolic tangent function were used to fit the impact absorbed energy and brittle fracture ratio, the special proportion fracture morphology transition temperatures F_{ATT SEPC} and the special absorbed energy transition temperatures E_{TT AV} were calculated, and the calculated results were compared and analyzed. The results show that for steel materials, both the transition temperature of fracture morphology and impact absorbed energy, the fitting results using hyperbolic tangent function and Boltzmann function by setting reasonable boundary value can be almost consistent. However, the physical meaning of hyperbolic tangent function is more clear, and it has more advantages in fitting some asymmetric transformation curves. Linear interpolation fitting can only roughly estimate whether the transformation temperature is qualified or not. When it is close to the required value, it can not be used to determine whether it is qualified or not. It also needs to use Boltzmann function or hyperbolic tangent function for accurate fitting.