叙述了超声波无损检测在机器制造、航空及铁路运输中的重要性及发展前途，分析了超声波在金属材料中的传播变化规律。采用了一个１６通道的声发射探伤系统，对油罐车、转向架侧架的损伤进行了实验分析，以实验方式确定了超声波速度在金属中的衰减过程，给出了具体零件的检测结果。 Describes the importance and development of ultrasonic non-destructive testing in machine building, aviation and railway transportation, and analyzes the variation of ultrasonic propagation in metal materials. A 16-channel acoustic emission testing system was used to analyze the damage of the tanker truck and the bogie side frame. The decay process of the ultrasonic velocity in the metal was experimentally determined, and the test results of the specific parts were given.