Abstract
Failure investigation was carried out on a 12'' water evaporator duct nozzle of a large-scale steam flood pilot which is used to inject steam into a heavy crude oil reservoir. The nozzle contained cracks at the pipe, shell, pad and welds. All the materials are made of UNS31803 grade 2205 duplex stainless steel. The cracks were initially formed at the welds and then propagated through the pipe, pad and shell. The cracks were running almost parallel in a straight manner. The cracks were transgranular in nature in the form of fissures associated with second phase precipitates. The results indicated that the nozzle was subjected to repeated welding thermal cycles and the heat input was relatively high, as manifested by the presence of intense heat tint, high percentage of austenite in the weld region (about 70%), and the presence of embrittling intermetallic phases. The investigation concluded that the primary reason of failure was poor welding practice, which facilitated brittle cracking. Fatigue was the mode of failure, which resulted from vibration in the piping system.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
