某换热器在长期使用后出现渗水和腐蚀现象，对其渗漏部位进行宏观检查、扫描电镜及能谱分析。结果表明：部分区域的铜焊料与不锈钢基体在焊接时未完全熔合；在换热器使用期间，多次热循环与水流周期性冲击使焊接未熔合区域的铜焊料与不锈钢基体分离，最终导致局部渗水。

Water seepage and corrosion occurred in a heat exchanger after long-term use. Macroscopic examination, scanning electron microscope and energy spectrum analysis were performed on the leakage site. The results show that the copper solder in some areas was not fully fused with the stainless steel substrate during welding. During the use of heat exchanger, multiple thermal cycles and periodic impact of water flow separated the copper solder from the stainless steel substrate in the unmelted area of welding, and eventually led to local water seepage.