Limiting conditions of pitting corrosion for lean duplex stainless steel as a substitute for standard austenitic grades

Lean duplex stainless steels such as EN 1.4162 (LDX 2101Ò) are today used in many applications where they can substitute for the standard austenitic stainless steel 304L and 316L. The advantages include higher strength, better resistance to stress corrosion cracking, good uniform corrosion resistance and better price stability due to the lower nickel content. This paper focuses on the performance of the lean duplex stainless steel LDX 2101Ò as a substitute for type 304L and 316L in chloride containing environments ranging from potable water to seawater. A combination of short term electrochemical testing and long term exposures is used to investigate the tendency to pitting corrosion as a function of chloride concentration and temperature. This is used to define the limiting conditions for pitting corrosion and construct engineering diagrams showing the risk areas for localised corrosion as a function of environmental parameters. Results are discussed in terms of the role of alloying elements and microstructure. QC 20191115