对焊根部位存在未熔透缺陷的长颈铜法兰和铜管焊接接头，进行了应力测试、超压试验和有限元应力分析。研究表明：焊根部位内表面受到轴向压缩应力的作用，深度在２ｍｍ以内的未熔透缺陷有闭合趋势，对焊接接头的强度影响很小，焊接接头仍可在正常工作条件下安全运行 Weld root part of the existence of imperfections in the long-necked copper flange and brass welded joints, stress tests, overpressure tests and finite element stress analysis. The results show that the inner surface of the root is affected by the axial compressive stress, and the unmelted defects with the depth less than 2mm have a tendency to close, which has little effect on the strength of the welded joint. The welded joint can still operate safely under normal working conditions