厚壁小径管对接焊缝的超声波探伤方法探讨

为确保600 MW机组的锅炉水冷壁系统在高温高压下能够正常工作,水冷壁系统的凝渣管道使用了厚壁小径管,为此,针对厚壁小径管对接焊缝采用超声波探伤时其壁厚在规程范围之外的问题,提出了用直射法超声波进行探伤的建议,并通过对不同规格探头的近场区长度、灵敏度余量及其能查到的焊缝厚度范围等的计算,对其可行性进行了探讨,并就其优缺点进行了分析.

Ultrasonic inspection for butt welds of thick-wall small-diameter tubes

To ensure the normal operation of the boiler water-cooled wall system of 600 MW units under high temperature and high pressure,thick-wall small-diameter tubes are used for the slag screen of the system.Aiming at the problem that the wall thickness exceeds the stipulation of relevant code during ultrasonic inspection for butt welds of thick-wall small-diameter tubes,this paper presents the method of direct supersonic test.Based on the computation of the near-field length,sensitivity margin and inspection thickness coverage of different kinds of probes,the feasibility of the method is approached and the virtues and defects are analyzed.