Influence of cold work and sigma phase on the pitting corrosion behavior of 25 chromium super duplex stainless steel in 3.5% sodium chloride solution

• Published in: Materials and corrosion Vol. 61; no. 3; pp. 199 - 204
• Main Authors: Elhoud, A., Ezuber, H., Deans, W.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.03.2010; WILEY‐VCH Verlag; Wiley-VCH
• Subjects: 25 chromium SDSS; Applied sciences; cold work; Corrosion; Corrosion environments; Exact sciences and technology; Metals. Metallurgy; pitting corrosion; sigma phase; Pitting corrosion; Work hardening; Austenitic ferritic steel; Stainless steel; Chromium; Duplex stainless steel; Sodium chloride; Dual phase steel; Surface treatment
• ISSN: 0947-5117; 1521-4176
• DOI: 10.1002/maco.200905312

The effect of cold work (up to 16% strain) and sigma phase precipitation (at 850 °C for 10 and 60 min) on the pitting resistance of 25 chromium super duplex stainless steel were investigated in 3.5% sodium chloride solution at 70 and 90 °C. Anodic polarization scans for cold worked samples revealed immunity to pitting attack at 70 °C even with 16% strain. At 90 °C, the alloy still showed high pitting resistance, pitting occurring at about 600 mV (SCE) for the 16% plastic strain samples. A serious deterioration of the pitting corrosion resistance was found after heating the alloy at 850 °C for 10 min resulting in a clear drop in the pitting potential at 90 °C. After heating for 60 min, the material showed rapid deterioration of pitting corrosion resistance at 70 °C.