利用斜探头对末级过热器联箱焊缝两侧进行常规扫查及斜平行扫查时, 不能有效地检测出焊缝可能存在的横向裂纹缺陷。为解决这一问题, 采用环向探测的超声波检测方法, 对某电厂末级过热器出口联箱焊缝进行了环向检测, 对缺陷回波的判定以及环向检测方法的影响因素等进行了分析和讨论。检测结果表明, 该检测方法能够有效地检测厚壁联箱焊缝存在的横向裂纹缺陷。

It is difficult to detect transverse crack in weld seam of high temperature superheater header in a power plant with traditional angle probe scan on both side of weld seam. To solve the problem, the method of circumferential detection was used to detect the weld seam. The defect echo identifying method and the influencing factors of circumferential detection method were analyzed and discussed. The result indicated that it was effective to test transverse crack in welding line.