Degradation of mechanical and corrosion resistance properties of AISI 317L steel exposed at 550 °C. (March 2016)

• Record Type: Journal Article
• Authors: Farneze, H.N.; Tavares, S.S.M.; Pardal, J.M.; do Nascimento, R.F.; de Abreu, H.F.G.
• Is Part Of: Engineering failure analysis. Volume 61(2016:Mar.)
• Page Start: 69
• Page End: 76
• Publication Date: 2016-03
• Subjects: AISI 317L -- Aging -- Pitting corrosion -- Deleterious phases; 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.2015.08.044
• Languages: English
• ISSNs: 1350-6307

Abstract

Abstract: The use of austenitic stainless steel type AISI 317L has increased in the last years, in substitution to AISI 316L and other austenitic grades. The higher Mo content (3.0 wt.%. at least) gives higher corrosion resistance to AISI 317L. However, some concern arises when this material is selected to high temperature process services in refineries. Microstructural changes such as chromium carbide precipitation and sigma phase formation may occur in prolonged exposure above 450 °C. In this work, the microstructure evolution of AISI 317L steel during aging at 550 °C was analyzed. Thermodynamic calculations with Thermocalc® and detailed microstructural analysis were performed in steel plate base metal and in weld metal produced by GTAW process. The aging for 200, 300 and 400 h promoted gradual embrittlement and deterioration of corrosion resistance of both weld and base metal. The results show that the selection of AISI 317L steel to services where temperatures can reach 550 °C is not recommended. Highlights: Toughness and pitting resistance of AISI 317L steel decrease with long exposition at 550 °C. Fine deleterious phases precipitates from ferrite at 550 °C. Deleterious precipitates of Cr23 C6, sigma (σ) and chi (χ) were identified by EBSD in weld metal aged at 550 °C.