某1Cr11Ni2W2MoV钢高压涡轮轴在进行疲劳试验后，其涡轮轴端面和轴体转接处存在沿圆周方向的长度为200 mm左右的穿透性裂纹。采用宏观观察、金相检验、断口分析等方法分析裂纹形成的原因。结果表明：该裂纹性质为疲劳裂纹，涡轮轴的材料正常，裂纹产生的主要原因是涡轮轴的上、下支撑板轴承安装孔同轴度偏差较大，导致涡轮轴在疲劳试验过程中呈偏转状态，最大应力位置发生改变，在端面和轴体的拐角处产生应力集中，促使裂纹形成。

After the fatigue test of a 1Cr11Ni2W2MoV steel high pressure turbine shaft, a penetrating crack with a length of about 200 mm along the circumferential direction existed at the end face of the turbine shaft and the shaft body. The causes of crack formation were analyzed by means of macroscopic observation, metallographic examination and fracture analysis. The results show that the crack was a fatigue crack, and the material of the turbine shaft was normal. The main reason for the crack was that the coaxiality deviation of the mounting holes of the upper and lower support plate bearings of the turbine shaft was large, which led to the deflection of the turbine shaft during the fatigue test. The maximum stress position changed, and stress concentration occured at the corner of the end face and the shaft body, which promoted the formation of cracks.