搅拌摩擦焊焊缝缺陷形态对超声相控阵检测的影响

Effect of friction stir welding defects morphology on phased array ultrasonic testing

搅拌摩擦焊缺陷界面紧贴、细微、取向复杂,常用的检测方法在角度选择及缺陷判别上存在难点,超声相控阵可在单一探头上实现多角度聚焦扫查。以不同形态未焊透(LOP)和隧道孔作为研究对象,采用超声相控阵扇扫,研究了界面取向和曲率对检测的影响。结果表明:超声相控阵扇扫可不移动探头对未焊透和隧道孔进行精确识别;平直未焊透界面检测受界面取向及入射角的共同影响,信号强度与声束和界面偏离垂直的程度呈反比,弯曲未焊透界面检测受界面曲率影响,信号强度与曲率成反比,综合多角度检测得到的角度-幅值曲线可以判断未焊透界面是否弯曲。

The defects of friction stir welding(FSW) are close and usually have complicated orientations, the commonly used methods have some difficulties in the selection of the angle and the identifying of defects, phased array ultrasonic testing can realize multi-angle focusing scanning by a single probe. Different morphologies of lack of penetration(LOP) and tunnel holes are taken as the research object, ultrasonic phased array S-scan was used to study the effects of interface orientation and curvature on the detection. The results show that the ultrasonic phased array S-scan can accurately identify LOP and tunnel holes without moving the probe. The detection of the flat LOP interface is affected by the interface orientation and the incident angle, the signal intensity is inversely proportional to the degree of deviation of the vertical reflection of the ultrasonic beam. The signal intensity is inversely proportional to the curvature of the interface when the LOP interface is curving. The angle-amplitude curve obtained by multi-angle detection can determine whether the interface can be used to determine whether the interface is curved or not.