Influence of heat treatments on the susceptibility of 9%Ni low carbon steel to sulfide stress corrosion cracking. (July 2020)

• Record Type: Journal Article
• Authors: Cunha, R.P.C.; Barbosa, C.; Barrozo, R.F.; Velasco, J.A.C; Tavares, S.S.M.
• Is Part Of: Engineering failure analysis. Volume 113(2020)
• Publication Date: 2020-07
• Subjects: 9%Ni steel -- Sulfide stress corrosion cracking; System failures (Engineering) -- Periodicals; Fracture mechanics -- Periodicals; Reliability (Engineering) -- Periodicals; Pannes -- Périodiques; Rupture, Mécanique de la -- Périodiques; Fiabilité -- Périodiques; Fracture mechanics; Reliability (Engineering); System failures (Engineering); Periodicals; Electronic journals; 620.112
• DOI: 10.1016/j.engfailanal.2020.104554
• Languages: English
• ISSNs: 1350-6307

Abstract

Highlights: The susceptibility of 9%Ni steel to sulfide stress corrosion cracking (SSCC) depends on the heat treatment. The material quenched without tempering and tempered at 400 °C is very susceptible to SSCC. Single tempering at 600 °C is better than quenching lamerising and tempering treatment as regard to SSCC. Abstract: Low carbon steels with Ni addition are selected to low temperature and cryogenic services. Recently, 9%Ni low carbon steel has been selected to cryogenic pipes and vessels in the oil and gas off-shore platforms where traces of H2 S may be present in the fluid process. In this work, specimens from a 9%Ni low carbon steel were submitted to four different heat treatments: quenching (Q), quenching and tempering at 400 °C (QT400), quenching and tempering at 600 °C (QT600), and quenching, lamellarizing and tempering (QLT). The susceptibility to sulfide stress corrosion cracking (SSCC) was evaluated by slow strain rate tensile tests (SSRT) in aqueous solution with pH 2.7–3.0 and H2 S partial pressure of 20 mbar. Condition QT600 was the less susceptible to SSCC. The results were discussed taking into account the microstructural analysis performed by scanning electron microscopy and magnetic measurement of austenite.