Experimental and Comparative Study of the Corrosion Behavior of Lean Duplex Stainless Steel in Seawater

ABSTRACT This study investigates the localized corrosion resistance of lean duplex stainless steel S32202 (EN 1.4062) in natural seawater. Its performance is compared to that of austenitic stainless steel 316 L (EN 1.4404), standard duplex S32205 (EN 1.4462), and super duplex S32750 (EN 1.4410) stainless steels. Crevice and pitting corrosion tests are conducted following the ISO 18070:2015 and ASTM G150 standards, respectively. The results indicate that EN 1.4062 exhibits superior critical pitting temperature and higher crevice corrosion resistance compared with EN 1.4404. Under a severe combination of conditions: a 20°C water temperature, a gasket pressure of 20 N/mm 2 , and a surface roughness of Ra = 0.3 ± 0.1 μm, even the higher‐grade EN 1.4462 and EN 1.4410 may be susceptible to crevice corrosion. These findings suggest that EN 1.4062 may be suitable for certain short‐term seawater applications, either independently or in combination with corrosion protection strategies.