弯管焊缝超声波探伤伪缺陷波分析

Analysis of Pseudo Defect Wave for Ultrasonic Testing of Bend Weld

对某油气输送管线焊接施工项目现场的弯管焊缝进行超声波探伤验收,发现多根弯管焊缝出现疑似超标回波。为了判定该超标回波的准确性,采用X射线拍片以及更换多种角度超声探头对超标回波进行分析,验证了超标回波为伪缺陷波显示,并分析了伪缺陷波产生的原因。提出了采用X射线拍片、打磨焊缝余高和在焊缝根部位置振动耦合剂辅助判别或增加不同角度的探头进行检测辅助判别的建议。

Ultrasonic inspection for acceptance of bend welds of an oil and gas transmission pipeline welding construction project was conducted,and suspected echoes exceeding the standard were found in a number of bend welds.In order to accurately determine the authenticity of the exceeded echoes and avoid misjudgment,it was verified that the exceeded echoes were pseudo-defect wave display by X-ray reexamination and waveform analysis by replacing multi-angle ultrasonic probes.The causes of the pseudo-defect wave were analyzed,and some reasonable suggestions were put forward,such as verfication by using X-ray radiography,polishing the weld reinforcement,flapping the coupling gel at the root position or using aditional different angle probes to assist discrimination.