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  • Stainless pipe

    Stainless pipe

    Have been asked to weld food grade stainless pipe by butting the two pieces together without a filler any advice using a miller synchro wave 210 pipe is about 75 thousands iv had a couple successful welds with the pulse turned up all the way at about 40 amps

  • #2
    What size of tungsten are you using? Also the type? How's it ground as far as taper is concerned? I'm assuming you have a purge going on? What makes a successful weld and what's a failure?

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    • #3
      40 thousands tungsten 2% Ceriated not much taper just enough to clean up the edge a failure would be blowing through if there is just a slight gape

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      • #4
        Ok. Now ask the important questions, is it the current that's to high, the on, on too long, or the speed and rotation in progression not quick enough? Is it a wave form response issue? It could also be arc length as an issue? Your using a cycle of on and off, high and low, with duration. After that it's arc length and speed of travel. Not much help but something to give some thought to in speeding up the practice curve. I'm not sure where the dials are set but remember the middle of 1 and 10 is 5. So it is between 4 and 6.
        You mention 40 amps, that could be a little hot still? Or maybe it's fine but the length of time on is too long? How big is the melt? What's the tube diameter?
        Another approach is melt fuse and stop. Repeat. Not the quickest but gets it done. One over lapping spot at a time?

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        • #5
          Large cup, #12 minimum. 40 ish amps is about right. Don't care for the pulse myself, I've seen no advantage, but you can experiment with it. Go slow especially when starting and wait for the puddle to swirl. If the puddle is swirling it is fusing inside. You should have 100% penetration, or no missed edges, if you do you didn't wait for the puddle to swirl. Have some 1/16" filler rod handy in case it opens up on you. If the fit up is tight it shouldn't be needed.

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          Last edited by Willvis; 05-10-2019, 04:11 PM.
          www.silvercreekwelding.com

          Miller Trailblazer 325 efi
          Miller extreme 12vs
          Thermal arc 186 ac/dc
          Lincoln power wave 455m/stt with 10m dual feeder

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          • #6
            Weld prep is very important, if this isn't right then the weld won't be as well

            must have a good purge, can't have too much pressure or it will push the weld up making the inside concave, or worst case blow through the puddle

            parts have to be clean and ends must be cut square

            fit up with no gaps

            never heard of using pipe but then I don't know it all, always tubing, I would think pipe would not have a food grade surface

            You can google sanitary welding for more
            Richard

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            • #7
              It's pretty common for sanitary tubing to be welded without filler. Ltbadd nailed it, for up has to be spot on.

              As for pulse, I have come to appreciate it. It's not magic, but the times I've used it the outcome has been very favorable.

              Also take time to prep your tungsten extra nice. Sharp and polished, it will give you the best arc start you can ask for.

              Willvis mentioned the large cup, I completely agree, if you have one or can get one by then. Use every tool you can to give yourself the best chance for success.

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              • #8
                Im guessing he meant tube. Ive only seen food grade / sanitary in tube size aswell. I agree a good fitup makes it much easier. I recently did a bunch for a dairy farmer up the road and I started using my dry cut saw. Super quick and perfectly square cuts. Sure beats a wrap around and zip cut. Ya once your purged you only need 5 or less cfm. Just enough to keep a slight possitive preasure. Ive seen good results with pulse settings on orbital welders but in my limited experience I never found it helped me that much. I found its harder to see the puddle swirl on pulse because of the flashing light and as I said thats the key to getting good fusion inside
                www.silvercreekwelding.com

                Miller Trailblazer 325 efi
                Miller extreme 12vs
                Thermal arc 186 ac/dc
                Lincoln power wave 455m/stt with 10m dual feeder

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