采用宏观观察、化学成分分析、金相检验、氨重试验以及能谱分析等方法对凝汽器铜管存在坑点腐蚀的原因进行了分析。结果表明:在黄铜管的加工中使用了热裂解性能较差的内模拉伸润滑油而使其内壁粘附着炭质沉积膜,加上黄铜管未采用硫酸亚铁成膜处理以及机组运行中也未进行定期胶球清洗等是造成其腐蚀的因素,其中炭质沉积膜的存在是导致黄铜管在冷却水的作用下形成坑点腐蚀的主要原因。提出了预防凝汽器黄铜管坑点腐蚀的对策。

By macro examination,chemical composition analysis,metallographic examination,ammonia fume experiment and energy spectrum analysis,the cause of tubercular corrosion on brass tube of condenser was analyzed. The results showed that one of the causes of the tubercular corrosion was the deposit carbon film on inner surface of brass tube,which was created by thermal decomposition of low quality stretching lubricant oil during annealing process of brass tube. Furthermore,neither precoating nor ball cleaning might enhance tubercular corrosion when brass tube came into operation. Doubtless the existence of deposit carbon film was the most important cause of bubercular corrosion. And countermeasures against tubercular corrosion were presented.