化工厂水冷壁管腐蚀减薄原因分析

某化工厂在大检修时发现热电运行部1号炉水冷壁管出现严重的腐蚀减薄,对该管道进行壁厚测量、向火面部位的取样,采用化学成分分析、金相组织分析、扫描电镜及EDS能谱分析等方法,确定该管道的化学成分符合标准要求、金相组织为铁素体+珠光体,珠光体二级球化,未发现异常组织,外表面腐蚀层含有大量的O、S等元素,其腐蚀类型为水冷壁管常见的外侧高温烟气腐蚀,并提出减缓对策和措施。

Cause Analysis of Water Wall Tube Corrosionand Thinning in Chemical Plant

During the overhaul of a chemical plant,it was found that the water wall tubes of No.1 boiler of the thermal power operation department were seriously corroded and thinned,the wall thickness of the pipeline was measured and samples at the fire direction were taken.Chemical composition analysis,metallographic structure analysis,SEM and EDS were used.It was determined that the chemical composition of the pipeline meets the requirements of the standard,the metallographic structure is ferrite+pearlite,the pearlite is spheroidized in two stages,no abnormal structure is found,the outer surface corrosion layer contains a large number of O,S and other elements,the corrosion type is the common outer high temperature flue gas corrosion of water-cooled wall pipe,and the corresponding mitigation measures are put forward.