Austenitic and duplex stainless steels are often used in corrosive environments due to their excellent corrosion resistance. These materials are chosen for their improved corrosion resistance but at an increased material cost. The improved corrosion resistance can be quickly negated by final installation techniques. Improper welding techniques can reduce their corrosion resistance and can make them more susceptible to failure. This paper presents several case studies in which welding negatively affected the corrosion resistance of the stainless steel components. Failure modes include preferential attack of microstructural features, galvanic corrosion, MIC, and creep. Improper welding caused the formation of undesirable microstructure, high residual stresses, and other conditions affecting the material’s corrosion resistance. Stainless steel materials investigated include Type 304, Type 316, and Type 2205 used for piping, flanges, and other fittings.

Subject
Weld attack, Materials, Piping, Microstructure, Precipitates, Welding, Flanges, Metallographic examination, Mechanical failure, Corrosion resistance, Stainless steel, Ferrite, Microbiologically influenced corrosion
Keywords:
austenitic stainless steel, duplex stainless steel, welding, MIC, pipe, flange
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2020
Association for Materials Protection and Performance (AMPP)
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