直缝埋弧焊管扩径裂纹的超声波检测方法

为了提高钢管超声波探伤的准确率，对射线检测可能出现漏检或误判的情况进行了研究，并对钢管扩径裂纹进行了系统分析及实物检测对比试验。结果表明，在确定探头K值后应尽可能采用短前沿的、晶片尺寸和探头外观尺寸较小的探头，可获得良好耦合效果；为减少漏检，应确保在焊缝两侧均进行一次直射波和二次反射波的扫查探伤；探伤过程中发现回波坐标位置处于探头一侧的焊缝边缘时，则可判定为扩径裂纹缺陷；回波坐标位置处于探头另一侧的焊缝边缘部位，则不能确定为缺陷波。

Ultrasonic Testing Method of SAWL Steel Pipe Expanding Diameter Crack

In order to improve the accuracy of ultrasonic inspection of steel pipe, the situations of missing detection and misjudgment were researched, the steel pipe expanding diameter crack was systematically analyzed and tested by contrast tests.The results showed that probes with short front distance, small size chip and small apparent size had better coupling effect after confirming the K value of probes;for reducing missing detection, scanning inspections of primary direct wave and secondary reflected wave should be tested in both sides of the weld; when echo coordinates located in the same side of the weld with the probe, it could be judged to be expanding diameter crack defect; when echo coordinates located in the other side of the weld with the probe, it could not be judged to be defect wave.