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

Abstract

Stress corrosion cracking behavior of quenched and tempered 2.25Cr 1Mo steel T Manzoor, E Ahmad, M Sarwar et al. Abstract. 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.

Combating the Tribo-Corrosion of LDX2404 Lean Duplex Stainless Steel by Low Temperature Plasma Nitriding

“…The surface morphology of the untreated and plasma nitrided samples after the corrosion tests is shown in Figure 6. The surface of the untreated sample exhibits severe corrosion pits and selective corrosion along elongated grain boundaries with ferrite grains being corroded (Figure 6a) [16]. SEM observations on the surfaces of PN390 sample revealed no notable change after the corrosion test, indicating an improvement in the corrosion resistance over the untreated material (Figure 6b).…”