镀锌边板对铜管换热器腐蚀影响机制研究

Study on influence mechanism of galvanized plate on corrosion of copper tube heat exchanger

目前市场上用量最大的铜管换热器,多使用镀锌边板作为右支撑,镀锌边板的腐蚀电位较低,可以与铜管耦接,对铜管起到保护作用。然而,对市场上回收样机进行分析发现,约43%的换热器在镀锌边板附近发生泄漏。通过对不同运行周期的换热器进行分析发现,在使用初期,镀锌边板对铜管可起到保护作用,随着使用时间延长,保护作用逐渐降低,镀锌层被消耗以后,铁基体开始被腐蚀出现铁离子,这会加速铜管的腐蚀。

The most used copper tube heat exchanger in the market uses galvanized plate as the right support. Because of the low corrosion potential of galvanized plate, it can be coupled with copper tube, which protects the copper tube. However, the analysis of recovered prototypes on the market reveals that about 43% of the heat exchangers leakeage is near the galvanized plate. Through the analysis on the heat exchanger with different operating periods, it is found that the galvanized plate can play a protective role on the copper tube in the early stage of use. With the prolongation of the use time, the protective effect is gradually reduced. After the depletion of the galvanized layer, the iron matrix begins to corrode with the iron ions, which promotes the corrosion of the copper tube.