１前言天津市某发电厂３＃炉汽包集中降水管采用翻边接管结构。近期检查时在全部六条降水管接头内壁高压区域内（翻边接管沿汽包轴向两侧）发现大量断续、密集的表面裂纹，单条裂纹最长约为３０ｍｍ，最深为６．５ｍｍ。裂纹分布沿经向长约２５０ｍｍ，沿环向约１６０ｍｍ... 1 Preface Tianjin Power Plant 3 # furnace drum centralized precipitation pipe with flange over the structure. During the recent inspections, a large number of intermittent and dense surface cracks were found in the high pressure area of ​​the inner wall of all six plumbing joints (flanges taken along the axial sides of the drum). The maximum length of a single crack was about 30 mm and the maximum depth was 6.5 mm. Crack distribution along the warp length of about 250mm, along the ring about 160mm ...