This topic contains 0 replies, has 1 voice, and was last updated by 
-
Posts
-
We are assessing the remaining life of our 304H SS expander inlet line operating around 1200F. Extensive renewal of the 42″ / 24″ piping and expansion bellows was previously performed in 1993 after 22 years service due to numerous cracks at circumferential welds and attachments. The damage was attributed to sigma phase embrittlement. Creep damage may have also been a factor. Existing base metal and welds are currently showing significant sigma phase along with carbide precipitation. Crack repairs were required on several attachment welds during the last shutdown.
– How long have other facilities operated hot wall lines prior to replacements? What has been the severity of cracking? Have successful repairs been made to operate until the next shutdown? Has solution annealing been required to restore weldability?
– Have any facilities established a criterion for much sigma phase is acceptable? If so, was this based on a correlation with impact testing results?
– Have any facilities experienced on-stream weld failures?
You must be logged in to reply to this topic.