球形封头环缝TOFD检测可行性试验研究及应用

The Feasibility Test and Application to The Detection of The Circumferential Seam of a Dome Head by TOFD

锅炉和压力容器球形封头环缝采用衍射时差法(TOFD)检测时,由于封头侧有弧度影响,造成主声束角度不一致、聚焦点位置发生偏离和传播声程不同等因素变化,所以行业内普遍认为球形封头环缝TOFD检测可靠性较差,因此目前封头环缝主要采用射线照相(RT)检测。本文介绍了球形封头环缝用工艺修正方法进行TOFD检测的可行性试验,获得检测数据及检测结果,并在工程中得到实际成功应用。

It is regarded almost impossible to apply TOFD ultrasonic testing techonology to the detection of the circumferential seam of a dome head in a boiler or a pressure vessel because of the arc on the side of the dome head,which causes the disagreement of main acoustic beam angles,the offset of the focus location,the difference of sound transmission distance,and some other changes.Therefore,when comes to the circumferential seam of a dome head,the radiographic test(RT)is still mainly used at present.This paper introduces the feasibility test to the detection of the circumferential seam of a dome head by TOFD ultrasonic testing techonology with corrected values,as well as the data and the result acquired from the test,and it is successfully applied in engineering.