对加垫板管对接焊缝进行超声波检测时，反射信号与焊缝内部的焊接缺欠信号易混杂在一起而干扰检测人员对缺欠信号的识别，影响检测结果的准确性和可靠性。对此类对接焊缝超声检测时不同部位以及相应缺陷产生的回波信号位置、特征等进行了详细叙述，给出了焊缝内部缺欠显示波和焊缝外部非缺欠显示波的区分方法，以为同行对该类结构的检测提供参考。

On ultrasonic testing of add liner plate pipe butt weld, the reflected signal is easily mixed together with the welding defect signal, which shall interfere the testing personnel in defect signal recognition and affect the detection accuracy and reliability. For the purpose of promoting the ultrasonic testing of the pad added pipe butt weld, detailed descriptions of echo signal position and characteristics corresponding to different parts and defect are presented in the paper, and the method to distinguish the weld defect display and weld external non-defect display are also given, thus providing a reference for the inspection of the above-mentioned structural defects.