介绍了一种利用相控阵超声技术结合专用的Cobra扫查器，对小径管环焊缝进行检测的方法。该方法符合ASME B31标准，是一种小径管射线检测的完全替代技术。通过试验和客户现场检测应用，该方法可对21~114 mm小径管进行环焊缝检测，并可进入狭小空间进行检测。由于其曲面晶片的特性，其检测结果比线性晶片的检测精度更高。对碳钢和不锈钢都可进行检测。检测前可对检测进行模拟，检测后可对检测结果进行精确地分析。

This paper is about using phased array ultrasonic testing method with special Cobra scanner to inspect small diameter circumference welding. This method complies with ASME B31 code, and is a kind of complete substitute method of X-ray inspection. After the experiment and on field testing, this method can test small diameter pipe with diameter 21 mm to 114 mm, and can access limit space. Because of the characteristic of curved element probe, curved probe testing result is better than linear probe on accuracy. This method can test both carbon steel and stainless steel. This method can do simulation before testing and can analyze accurately after the testing.