Pitting corrosion behaviour in sodium chloride solution of intermetallic centreline stringers in super duplex stainless steels

• Published in: Corrosion science Vol. 223; p. 111482
• Main Authors: Erazmus-Vignal, P., Vignal, V., Huguenin, P., Krajcarz, F.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2023; Elsevier
• Subjects: Chemical Sciences; Corrosion; Polymers; Sigma phase; Super duplex stainless steels; Sigma phase; Corrosion; Super duplex stainless steels; corrosion; super duplex stainless steels; sigma phase
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2023.111482

Although manufacturers have optimized metallurgical routes to deliver super duplex stainless steels free from intermetallic phases, a segregated zone is generally formed close to mid-thickness for flat products. This zone may contain a small amount of sigma phase particles in the form of centerline intermetallic stringers. In this paper, their corrosion behaviour is investigated in sodium chloride solution, by coupling non-electrochemical and electrochemical techniques at the global and local scales. Corrosion mechanisms at centerline intermetallic stringers is then discussed and weak points in the sample are identified. •Discontinuous centerline intermetallic stringers do not impair the overall pitting corrosion resistance of the alloy.•The weakest sites of the alloy contain oxide particles.•Sites containing sigma precipitates are sensitive to pitting corrosion only at very high values of the applied potential.