Corrosion Performance of the New ASTM S30416 (APM316A) Stainless Steel Grade in Water Networks

Abstract In water applications, materials are selected according to technical requirements such as corrosion resistance, ease to shape, weld, and costs. Austenitic stainless steel grades are standard materials used in these applications. The corrosiveness of the fluids is mainly influenced by the chloride content, chlorine, pH, temperature. Very often, grade S30403 is suitable for the chloride content. Where the chloride content exceeds the tolerance of S30403, a superior alloy such as S31603 is required. Considering the economic and ecological costs due to the Ni and Mo contents, a new, cost effective S30416 grade has been developed to achieve similar corrosion resistance to S31603 in the same range of media and temperatures. This study deals with the localized and general corrosion resistance of the S30416 grade compared with grades S30403 and S31603. Corrosion resistance was assessed using electrochemical methods: pitting potential was determined at different temperatures and chloride contents; polarizations were performed in acidic solutions to assess crevice and uniform corrosion. Intergranular corrosion was tested according to the ISO(1) 3651-2 method A. The results show that the new S30416 grade meets the expectations as it exhibits similar corrosion resistance to the S31603 grade. It has been registered in the European standard as well.