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Poland308
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Tube sheet is 1-1/4 inch thick. On a 600Hp steam boiler. Runs about 100-120psi
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Two different cracks on separate sides of the boiler. Both below the water line
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Josh
Poland308
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Started grinding it out but under the surface the cracks started to spiderweb. The metal Braganza to flake off as well.
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I have more questions than answers

Josh
Poland308
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I'll post more pics after I get home tonight.
I have more questions than answers

Josh
Poland308
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Metal is so stressed that it cracks at the edge of the haz as it cools
Metal is so stressed that it cracks at the edge of the haz as it cools
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Last 1/8 of thickness started to crumble
Last 1/8 of thickness started to crumble
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Welded it back out and smoothed it off
Welded it back out and smoothed it off
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I have more questions than answers

Josh
noddybrian
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Is it "normal" over there to weld tubes in ? I never heard or seen anything like it - ours are always expanded - depending on the number & spacing of stays & known history for tube end erosion they're sometimes belled ( I hate that job ! ) - kinda seems like with thermal movement from cold start up & dramatic thickness difference between tube plate & tubes they're going to crack - I seen emergency welded repairs to keep an old boiler going but not on this scale.
Poland308
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This boiler is about 35 years old. These were expanded in and then welded. It's not very common here either. This boiler had been retubed before about 17 years ago. But I believe they were welded when it came from the factory. We were all concerned that the metal was going to be brittle and unrepairable before we started, but it's for a Hospital so we tried anyway. Going to let our weld engineers decide if they want try cutting out all the tubes and replacing the whole tube sheet.
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Josh
PeteM
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I've done a few of those with the expander. We were warned very clearly before hand about over running/cracking them and what a pain it is to tear them out and do over. Then they got a tig root and mig cover.

Do you suppose that is what may have contributed to the failure, or are these just a matter of one every so many is going to crack and need repaired?
Poland308
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I've rolled in lots of tubes on lots of boilers and never had issues. I think these stem from the fact that they were welded from the beginning.
I have more questions than answers

Josh
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