近年来，铁道高速动车组空心车轴超声波探伤人工裂纹在原有弦长型模式的基础上，增加了等深型模式。另外，各空心车轴制造厂家的超声波探伤裂纹起始灵敏度也不尽相同。对此两个问题进行了试验研究，发现弦长型和等深型两种型式的人工裂纹是等效的；在一定角度的探头检测时，裂纹深度不同，反射当量基本相同。空心车轴疲劳裂纹采用38°斜探头检测效果最佳。

In recent years, ultrasonic testing artificial crack in high speed railway hollow axle increased depth mode in addition to the original chord mode. In addition, ultrasonic testing starting detection sensitivity is different between different hollow axle manufacturers. In this paper, through lots of research work on these two problems, the author found the manual crack were equivalent between chord mode and depth mode; in certain angle probe, different crack depth had the same sensitivity. It is better to use 38° angle probe to detect the fatigue crack of hollow axle.