Metallurgical investigations on corrosion behavior of simple and heat treated duplex stainless steel 2205 exposed to corrosive media

Abstract Duplex stainless steel 2205 has proven to be the most acceptable material for marine and saline applications because of its superior corrosion resistance with good erosion and wear resistance. However, the disadvantage of stainless steel is its sensitivity to local corrosion in a solution containing chloride, which limits their use in seawater systems. The effect of heat treatment on corrosion properties of stainless steels can be studied in marine or chloride environments and investigation of changes in microstructure and corrosive property. This study presents the consequence of heat treatment on the microstructure and corrosion resistance and systematic approach to examine the corrosion behaviour of plain DSS 2205. Precipitation of secondary parts in DSS 2205 led to an extreme reduction in its corrosion resistance and another factor contributing to changes in ferrite and austenite ratios where preferential corrosion occurred in the DSS 2205 ferrite phase. The austenite phase shows better corrosion resistance than the ferrite phase due to maximum Ni content than ferrite. Cr is the most active element in the passive film to develop the resistance of DSS 2205 to localized corrosion. The heat treatment about 1080°C to DSS 2205 improves the corrosion resistance of steel comparatively.