2507双相不锈钢钾盐蒸发罐腐蚀的原因分析

摘要

According to the case study of evaporators used in two projects of an institute,the reasons for corrosion cracking of 2507 duplex stainless steel evaporators were analyzed from the operational environment and manufacturing process.Furthermore,the ways to avoid the corrosion of duplex stainless steel evaporators were investigated from design,manufacturing and operation.The results show that both operational environment and manufacturing process have great influences on the corrosion of duplex stainless steel evaporators.Stress corrosion cracking occurs easily when there are welding flaws,stress concentration because of assemble residual stress on the evaporators,or they work in the conditions of strong acid,high temperature and solution with high concentration of Cl-.%以某院设计的两个项目中的蒸发罐实际使用情况为切入点,从2507双相不锈钢设备的使用环境和制作工艺两方面分析了钾盐蒸发罐发生腐蚀开裂现象的原因,进而讨论了如何在设计、制造及使用过程中避免双相不锈钢设备发生腐蚀.结果表明:双相不锈钢蒸发罐的使用环境和制造工艺均对其耐蚀性有很大的影响,尤其是当有焊接瑕疵和组装残余应力造成的应力集中,或在强酸、高温、高C1-含量介质溶液的环境中运行时,设备极易发生应力腐蚀裂纹.