液化天然气储罐9%镍钢焊缝相控阵AUT工艺

Phased Array AUT Technology for Testing of 9%Nickel LNG Storage Tank Welds

9%镍钢液化天然气储罐制造安装过程中,焊缝检验通常用常规射线照相(RT)进行。本文研讨用相控阵半自动超声检测(AUT)取代射线照相的工艺制定及验证方法。要领分四步:首先带缺陷专用焊接试样的制备;然后相控阵AUT工艺的编制;其次在有已知缺陷的焊接试样上,对AUT工艺作"开放性"验证试验;最后在现场对整个数据采集系统作"封闭性"操作演示和验证评定试验。验证结果表明相控阵AUT取代RT可行可靠,能凸显AUT种种优势。

During construction of 9 % nickel LNG （Liquefied Natural Gas） storage tanks, weld examination is often done by conventional radiography. This article discusses development of photographic process and verifies methods using phased array AUT （semi-automated ultrasonic examination） technology in lieu of radiography. The essentials are composed of the following four steps： firstly preparation of specific welded samples with known defects, secondly development of AUT procedure using phased array equipment, thirdly open trials on welded samples for verification of the AUT procedure, lastly blind trials at site for demonstration/qualification of complete acquisition system. The obtained results showed it was practicable and reliable to use phased array AUT in lieu of RT, thus displaying some advantages of AUT.