针对常规超声波缺陷回波法检测发动机盘、环件时难以发现垂直于端面的径向裂纹的问题，阐述了底波监控方法的原理和特点，根据试验结果得出结论：底波监控方法可有效地发现盘环件中材料微观组织的不均匀或材料中垂直于端面的宏观缺陷，采用该法可有效地避免此类缺陷漏检情况的发生。

Pointing at the poor ability to find the radial defect perpendicular to the outer surface in the engine disk and ring, this paper describes the principle and features of the bottom wave monitor method. According to test results, the monitoring method of bottom wave can effectively find defects perpendicular to the end plate and the nonuniformity in the material. So proposed method is called the back wave monitoring test method and it can avoid the undetected defects effectively.