Corrosion and metal release characterization of stainless steel 316L weld zones in whey protein solution

Abstract

Abstract Stainless steel ASTM 316 L is often used in the food industry as contact material with protein-rich dairy products. It has to be welded at some locations for many of these contact materials. This study aimed at i) determining any combined effects of the presence of whey protein (WP) and welding-induced weaknesses on corrosion and metal release, and ii) determining the appropriate welding procedure and filler metal (316 L, 309 L, 312). All weld metals (WMs) showed a higher pitting corrosion susceptibility as compared to the base metal (BM). Under induced friction (stirring), WP significantly enhanced the metal release from all materials, which was accelerated between 1 and 3 days of exposure. Post-imaging indicated pits. 312-WM released significantly higher amounts of metals as compared to the BM and the other WMs. This study indicated that the presence of WP, friction, and weldment-induced corrosion susceptibilities could synergistically cause metal release and corrosion of food contact materials.