通过理论分析并参照DL/T 820-2002标准，深入分析了奥氏体不锈钢小径薄壁管焊缝超声相控阵单侧扫查时探头及声束的布置、各种参数的设置原则、DAC的制作等，提出了缺陷评定时缺陷波幅及长度的确定方法。通过分析表明，对于该小径薄壁管的检测，超声相控阵技术可以得到与常规超声检测相同甚至优于常规超声的缺陷检出效果。

In this thesis, through theoretical analysis and referring to DL/T 820-2002 standard, inspection of small diameter austenitic steel tube weld at single side of the seam by using phased array method, was deeply studied. Deduced the principle of probe setting, ultrasound beam and other parameters configuration was deduced and skills of making DAC was introduced, and methods of measuring the echo amplitude and sizing the length of the defects were also raised. By means of technical analysis, it is indicated that, detection on small diameter austenitic stainless steel tube, equivalent to or better than detecting result can be achieved by phased array method than conventional UT.