2205双相不锈钢阴极线短时锈蚀原因

Causes of Short-Time Corrosion of 2205 Duplex Stainless Steel Cathode Line

国内某火电厂2号机组湿式电除尘器(WESP)阴极线在进行安装带电试验后发生了严重锈蚀,采用宏观形貌观察、化学成分分析、力学性能测试、金相检验、扫描电镜和能谱分析以及模拟冲洗试验,分析了阴极线发生腐蚀的原因。结果表明:在低浓度的Cl^(-)与SO_(4)^(2-)共同作用下,2205双相不锈钢阴极线表面的钝化膜在较短时间内发生了吸附和溶解,导致基体与潮湿的空气接触,从而发生腐蚀,形成以Fe_(2)O_(3)为主要成分的铁锈。

The cathode wire of wet electrostatic precipitator (WESP) of Unit 2 in a domestic thermal power plant was seriously corroded after the installation live test. The causes of corrosion of cathode line were analyzed by macroscopic morphology observation, chemical composition analysis, mechanical property test, metallographic examination, scanning electron microscopy, energy spectrum analysis and simulated flushing test. The results showed that the adsorption and dissolution of passivation film on the surface of 2205 duplex stainless steel cathode line was occurred in a short time under the combined action of low concentration Cl_(-) and SO_(4)^(2-), which led to the contact between substrate and humid air, resulting in corrosion and rust with Fe_(2)O_(3) as the main component.