基于超声TOFD技术检测缺陷位置和尺寸的原理，应用多通道超声TOFD检测系统检测了110 mm厚的2.25Cr1Mo钢试块中的横孔和切槽，给出了试块的D扫描和A扫描图像，分析了两者的对应关系。试验结果表明，缺陷位置和尺寸的误差<5%，验证了超声TOFD方法在缺陷定位和定量上具有较高的准确性。为应用超声TOFD设备进行现场检测时获得的自然缺陷图像的评定提供了有效的依据。

Based on the principle of ultrasonic TOFD technique for the detection, location and sizing of defects, the side drilled holes and notches in a 2.25Cr1Mo steel block of 110 mm in thickness were inspected using a multi-channel TOFD inspection system. The D scan and A scan images of defects were given .The corresponding relationship between D scan and A scan image was also analyzed. The errors of defects location and size were no more than 5%. The result validated the good measurement accuracy of ultrasonic TOFD testing. Thus, criterion was provided efficiently for evaluation of natural defect images examined by ultrasonic TOFD equipment on site.