Lean Duplex Stainless Steels in Wastewater Treatment Plants

Austenitic stainless steels (SS) S30403 and S31603 are commonly used for the construction of wastewater treatment units. Considering the cost, good corrosion resistance, and higher mechanical properties, lean duplex SS are a good alternative to these austenitic grades, but they are too rarely chosen, probably due to a lack of case studies. The localized corrosion performance of three lean duplex SS was assessed in solutions simulating pre-treatments unit waters and compared to two austenitic and two duplex grades. Results confirm that lean duplex grades S32101 and S32202 can be used as alternatives to S30403 and S31603, respectively, in these environments.