boiler water wall tube, restricted welding of B2 Chro-moly.
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  1. #1
    Join Date
    Mar 2012
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    Australia
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    464

    boiler water wall tube, restricted welding of B2 Chro-moly.

    I'm working on a brown coal power station boiler outage at the moment, once its finished I'll post a thread about the outage overall, but just a small job for today, this job is whats stopping them from pressure testing the boiler, so its critical path and hence why we're working our rostered day off on x4 normal rate.

    So my offsider and I had a nice little job today replacing two 8 inch sections of boiler water wall that had developed cracks and have been leaking for a while, these are the last two tubes in the corner of the boiler wall so it's quite tight getting to the sides of the weld, the night shift did a good job getting everything set up, cutting the tubes out with an oxy and prepping the tubes.

    this excellent MS paint picture represents on configuration of the tubes in the corner of the boiler, the two red circles represent the tubes being replaced.


    My offsider getting his TIG handpiece set up, the tubes a 28mm (about 1 and 1/8th inch) internal with a 6mm (1/4 inch) wall, B2 creep resistant steel which is 1.25% Chome and 0.5% Molybdenum


    Normally we'd use a pneumatic powered orbitalum brand prep machine like this but it was to tight to get it in the tubes, so the tubes had to be prepped by hand with a pnuematic barrel grinder with a carbide bit, the nightshift would have spent quite a while getting the preps to this level, if you want to weld in boilers get used to not having a perfect fit up, I recently watched a youtube vid on a restricted boiler weld test and thought "god you could drive a truck through that!" it can get pretty tight.



    and the two pup's welded in, I welded my side at around 170 amps for the root run and hot pass and 140 for the cap, my offsider likes it a bit colder at 100-120, this particular boiler run's at a pressure of 2400 PSI, at that pressure the water in these tubes doesn't boiler until about 300 degree's centigrade (about 570 F) so these tubes are under a considerable amount of stress hence the need for the creep resistant steel, the weld's are not pretty, but they passed x ray.

    Last edited by ttoks; 11-04-2018 at 12:22 AM.

  2. #2
    Join Date
    Mar 2017
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    Re: boiler water wall tube, restricted welding of B2 Chro-moly.

    What's the plan for getting the offside guy out of there?

  3. #3
    Join Date
    Mar 2012
    Location
    Australia
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    Re: boiler water wall tube, restricted welding of B2 Chro-moly.

    he's on the outside of the boiler on a scaffold, but I doubt anyone would mind if we left him there

  4. #4
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    Re: boiler water wall tube, restricted welding of B2 Chro-moly.

    Just checking, way you guys do everything upside down and counter rotating it never hurts to check.

  5. #5
    Join Date
    Mar 2011
    Location
    Western Washington
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    1,146

    Re: boiler water wall tube, restricted welding of B2 Chro-moly.

    Hmmmm... wait a minute.... if he's on the outside...then you're inside!!! you're trapped.

  6. #6
    Join Date
    Mar 2012
    Location
    Australia
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    464

    Re: boiler water wall tube, restricted welding of B2 Chro-moly.

    I am trapped!! Except for the man sized access door in the hearth I guess hana

    Sent from my R7sf using Tapatalk

  7. #7
    Join Date
    Mar 2017
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    Re: boiler water wall tube, restricted welding of B2 Chro-moly.

    Quote Originally Posted by ttoks View Post
    I am trapped!! Except for the man sized access door in the hearth I guess hana

    Sent from my R7sf using Tapatalk
    Hopefully you got friends on the outside who will pass food in to you.
    Meantime make sure to hang onto something larger than you and valuable enough to the company they won't leave it inside.

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