Repair to boiler
Repair to boiler
(OP)
i am repairing ligament cracks in a scotch boiler tubesheet. Do i need to postweld heat treat and hydro test? I'm in a State with no boiler code.
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RE: Repair to boiler
What is the tubesheet thickness and are these through-wall cracks??
RE: Repair to boiler
IMO it is always a good idea to stress relieve a full penetration repair to a boiler tube sheet. NBIC allows you to perform weld repairs without PWHT, regardless of tubesheet thickness, using one of several techniques ranging from a simple preheat with interpass temperature restriction to preheat plus temperbead techniques. Type of repair depends on type of material, age of material, condition of material, thickness of material (corroded or uncorroded), temperature of the tube sheet during normal operation, stresses on tube sheet, so on and so on.
Given that, after completion of the repair weld, I think it is also a good idea to hydrotest any repairs to the tube sheet. I have found leaks that way even after the PT showed no indications. Sounds strange since hydro is not a sensitive leak test, but just happended this week.
RE: Repair to boiler
RE: Repair to boiler
Regarding hydrotest, I would not perform a "code" hydrotest, instead I would perform a liquid pressure test. I don't believe in having an in-service component subjected to a "code" hydrotest (1.5 x MAWP).
RE: Repair to boiler