On the stress corrosion cracking of lean duplex steel in chloride environment

• Published in: IOP conference series. Materials Science and Engineering 2014-01, Vol.60 (1), p.12066-8
• Main Authors: Tayyaba, Qanita, Farooq, Hina, Shahid, Muhammad, Jadoon, Ammer Khan, Shahzad, M, Qureshi, A H
• Format: Article
• Language: English
• Subjects: Austenitic stainless steels; Carbon steels; Chlorides; Corrosion; Corrosion rate; Corrosion resistance; Corrosion resistant steels; Corrosion tests; Duplex stainless steels; Electrode polarization; Elongation; Localized corrosion; Pitting (corrosion); Pulp & paper mills; Slow strain rate; Sodium chloride; Stainless steel; Stress corrosion cracking; Stress strain curves; Stress-strain relationships; Uniform attack (corrosion); Weight loss measurement
• ISSN: 1757-8981; 1757-899X
• DOI: 10.1088/1757-899X/60/1/012066

Duplex stainless steel having attractive combination of austenitic and ferritic properties is being used in industry such as petrochemical, pulp and paper mills. In this study, the corrosion and stress corrosion behavior of duplex stainless steel in 3.5% sodium chloride environment was investigated by weight loss measurements, electrochemical DC testing and slow strain rate test (SSRT). Weight loss data showed no significant corrosion after 1700 hours. Electrochemical polarization test in 3.5% NaCl solution exhibited a uniform corrosion rate of 0.008 mpy (calculated using Tafel analysis) showing passivity in the range of 735-950 mV. A comparison of the slow strain rate test in 3.5% NaCl solution with air shows almost a similar stress strain curve for duplex stainless steel. In comparison, the stress strain curves for 0.15% carbon steel show a loss of about 25% tensile elongation for the same comparison. The excellent corrosion and especially resistance to localized corrosion (pitting) is responsible for no loss of ductility in duplex stainless steel.