我们在检验中发现,立式蒸汽锅炉汽水分界线处,冲天管腐蚀比较严重。其冲天管局部腐蚀的主要原因。有以下几个方面。 (1)水线腐蚀。即:在金属上留下一条平行于水线的凹槽,这种腐蚀将无限地进行下去。 (2)钝化膜的破裂。当锅炉运行时,水位线的上、下波动,不停地冲刷冲天管管壁,可导致水位线处的钝化膜破裂。另外,锅炉冷热交替,会引起疲劳应力也可使钝化膜发生破裂。 (3)温度的影响。温度升高,可使腐蚀速度加快。我 We found in the test, vertical steam boiler water boundaries, the sky tube corrosion is more serious. The sky tube corrosion of the main reasons. There are several aspects. (1) water line corrosion. That is: leaving a groove parallel to the waterline in the metal, the corrosion will continue indefinitely. (2) Passivation film rupture. When the boiler is running, the upper and lower water level lines fluctuate and the scouring pipe wall is constantly being washed, which can lead to the rupture of the passive film at the water level line. In addition, the boiler alternating hot and cold, can cause fatigue stress can also passivation film rupture. (3) the impact of temperature. Temperature increases, can make corrosion faster. I