With lower alloying cost and higher mechanical properties, lean duplex stainless steels can be an alternative to the more commonly used austenitic stainless steels. However, these alloys are still not the preferred choice, probably due to a lack of field experience. A study was thus initiated in view of defining the limits of use of selected (lean) duplexes for urban wastewater treatment units. The present paper shows the localized corrosion performance of selected lean duplexes in chloride contaminated solutions. The results are compared with austenitic S30403 and S31603 and with the more standard duplexes S82441 and S32205. The effect of welding was also investigated. Exposures in field municipal wastewater plants were conducted for 1 year in low and high chloride content units. The results show that lean duplexes S32101 and S32202 can be used as alternatives to S30403 and S31603 in low chloride electrolytes. At 500 ppm of chloride content, duplex stainless steel S32304 showed better corrosion resistance than S30403 and S31603. For higher chloride contents (1000 ppm and above) the standard duplexes S82441 and S32205 shall be preferred.

中文翻译：

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城市污水处理厂浸入式装置中（贫）双相不锈钢的局部腐蚀

凭借较低的合金成本和较高的机械性能，贫双相不锈钢可以替代更常用的奥氏体不锈钢。然而，这些合金仍然不是首选，可能是由于缺乏现场经验。因此启动了一项研究，以确定城市污水处理装置所选（精益）双工的使用限制。本论文显示了选定的贫双相化合物在氯化物污染溶液中的局部腐蚀性能。将结果与奥氏体 S30403 和 S31603 以及更标准的双相钢 S82441 和 S32205 进行比较。还研究了焊接的影响。在现场市政污水厂中，在低氯和高氯含量装置中进行了 1 年的暴露。结果表明，在低氯电解质中，贫双链体 S32101 和 S32202 可用作 S30403 和 S31603 的替代品。在氯化物含量为 500 ppm 时，双相不锈钢 S32304 表现出比 S30403 和 S31603 更好的耐腐蚀性。对于较高的氯化物含量（1000 ppm 及以上），应首选标准双链体 S82441 和 S32205。