I understand that manufacturer recommendations should be followed when welding in valves of all types but my question is, "what is the reasoning why some would recommend, say gates, to be in the closed position when others say to have them open". My question also relates to PWHT, which seems to...
Has anyone encountered cracking or distortion on an F91 gate valve welded to a P91 pipe during new construction due to improper installation? And if so was a root cause determined?
