Failure analysis of areal gas distribution skirt plate. (January 2022)

• Record Type: Journal Article
• Authors: Mohapatra, J.N.; Kulkarni, Ravindra; Satish Kumar, D.; Balachandran, G.
• Is Part Of: Engineering failure analysis. Volume 131(2022)
• Publication Date: 2022-01
• Subjects: AISI310S steel -- Sigma phase embrittlement -- Failure -- Microstructure and Mechanical properties; 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.2021.105885
• Languages: English
• ISSNs: 1350-6307

Abstract

Highlights: σ -phase embriittlement of 310S AGD skirt plate Drastic drop in tensile elongation and charpy impact energy. Intergranular brittle failure with large number of cracks at grain boundary. Restoration of properties by solution annealing treatment. Abstract: A detailed failure analysis was carried out on a skirt plate used in the reduction shaft of Corex plant at Areal Gas Distribution that failed after seven years of service. The analysis involved composition, hardness, mechanical properties, impact toughness, microstructure and phase analysis in the failed plate, and after solution annealing the plate for different lengths of time. It was found that the plate completely embrittled due to formation of massive Cr23 C6 type carbides and σ-phase (FeCr) for prolonged service at high temperature (~ 850 ° C), observed through microstructure and EDS analysis).The elongation of the steel was reduced to 1–4% and impact energy dropped to 5 Joule due to the embrittlement. The fracture surface showed intergranular brittle failure. After solution annealing treatment, the massive carbides and phases were mostly dissolved resulting in the restoration of the property. Hence it is suggested for solution annealing treatment in the in-service plates to improve their life. In addition, periodic monitoring of the plates through replica test and NDT could help in assessment of health of the plates for preventive measure.