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Welding Stainless Steel

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  • Welding Stainless Steel

    I don't have enough generator to run my TIG equipent at the track/salt, so the header failure this year convinced me it was time to learn how to weld stainless steel with a torch. I read the section of the Linde Oxy-Acetylene Handbood, mixed a fresh batch of Solar Flux and gave it a try.



    material: .060 wall, 1-5/8 diameter 304 stainless steel tubing.
    filler: 308
    prep: square cut, 1/32 gap
    torch: Smith AW1 with AW201 tip.
    flame: neutral
    flux: Solar Flux type B, mixed with 70% isoproply alcohol, applied inside and
    out . . . filler too.

    Is this the way the bead is supposed to look? The flux wanted to flake off the tube before a puddle formed, but flux from the filler appeared to protect it.

    For the photo the flux was removed with a bead blaster, then very lightly brushed with a rotary wire wheel to make it easier to see.

    Jim
    Dynasty 300DX
    MM350P
    Hobart Handler 120
    Smith LW7 , AW1A
    Smith He/Ar gas mixer

  • #2
    Looks good.....but maybe........

    Your weld looks good except for the roughness of the weld beads. Welding stainless requires a carburizing flame...excess acetylene...as you probably know. Try lowering the pressure from your torch a bit if you can to make the weld beads a bit smoother. Your beads look as if they were blasted too hard by the pressure from the torch. Jut my opinion. Others may disagree.

    When you welded the SS tubing, did you add argon to the inside of the tube to prevent sugaring? When welding stainless tubing, if possible, I add argon to the tube and plug up the ends to prevent oxygen from the air contaminating the penetration of the weld. Seems stainless steel tubing is prone to sugaring. I've had stainless tubing on an exhaust system break at a weld when I did not add argon to the inside and I learned from my mistakes. The weld was not as strong as I thought because of the oxygen contamination of the weld inside the tube. It was a set of headers I built for a friend and it looked great. But the welds cracked. I built a new set of headers for him and they never cracked after adding argon.
    Cobra 2000 A/O torch ( all USA made)
    Everlast Powertig 250EX (US company, Chinese MFG)
    Everlast Powerplasma 50 (US company, Chinese MFG)
    Hobart Handler 210 (US company, Chinese parts)
    GoWeld portable mig (US company, Chinese parts)
    Evolution rage 2 cold saw (USA company, USA parts)
    various other metal working tools

    Comment


    • #3
      Hey Jim,
      Your welds look good if this was your first attempt with O/A. I would add a bit more filler as your bead looks a bit weak. I'd also try to reduce your O2 a bit to see if the filler lays a bit smoother. It's good to see others getting into O/A as it can be a real joy to use & can go anywhere. After a couple more pieces, make a cut & check cross section fillet for internal voids. Looks like you'll be doing it quite handily as it's the same as TIG..... just a different heat source.

      To Steve: If you read Jims' posting of setup parameters, he indicated he used Solar Flux B for shielding. Are you familiar with it? It's the reason he wants to weld in the field by using O/A & without having to use a bottle of argon to purge as with TIG.

      Denny
      Complete weld/mach./fab shop
      Mobile unit

      "A man's word is his honor...without honor, there is nothing."

      "Words are like bullets.... once they leave your muzzle, you cannot get them back."

      "I have no hesitation to kill nor reservation to die for the American Flag & the US Constitution."

      Comment


      • #4
        HI Denny.

        Yes I am familiar with Solar Flux B. I must have missed that part of his post.

        I sometimes am too fast at reading and posting. Solar Flux B is good for some tubing joint but not all. I have used it in the past, but when making a joint where one of the tubes is not accessible to the inside because of the length, I flood with argon. I kind of got into the habit of using argon just because of that. Solar Flux B is a great product and I probably should use it more as it is cheaper than flooding with argon. I have some of it floating around here somewhere. I'll have to find it. I guess old habits die hard.

        I might also recommend not using Solar Flux B on the outside of the weld. With stainless, I try to keep the weld as pure as possible. That's another reason why I flood with argon. Just to keep it pure. The DHC 2000 torch seems not to need any flux for stainless. That and a standard stainless tig rod and I'm set to go.

        For a first try at stainless, I would say you did a great job.
        Last edited by Steve from Ohio; 11-05-2010, 01:05 AM. Reason: added info
        Cobra 2000 A/O torch ( all USA made)
        Everlast Powertig 250EX (US company, Chinese MFG)
        Everlast Powerplasma 50 (US company, Chinese MFG)
        Hobart Handler 210 (US company, Chinese parts)
        GoWeld portable mig (US company, Chinese parts)
        Evolution rage 2 cold saw (USA company, USA parts)
        various other metal working tools

        Comment


        • #5
          Originally posted by yorkiepap View Post
          Hey Jim,
          Your welds look good if this was your first attempt with O/A. I would add a bit more filler as your bead looks a bit weak. I'd also try to reduce your O2 a bit to see if the filler lays a bit smoother. It's good to see others getting into O/A as it can be a real joy to use & can go anywhere. After a couple more pieces, make a cut & check cross section fillet for internal voids. Looks like you'll be doing it quite handily as it's the same as TIG..... just a different heat source.

          Denny
          One of my problems is keeping the flux from flaking off the tube before the flux melts. I mixed it a little thicker (less alcohol) and that helped the appearance of the bead, but it's really easily knocked off if anything touches it.

          The Linde book recommends a neutral flame to prevent carbon contamination of the weld, but I have been using a "slighly" reducing flame to make sure there's no excess oxygen.



          'Still having trouble getting complete penetration. The gap moves a lot more than I'm used to (closes up) with TIG. I'm sure that's part of it . . . and I may be moving too fast. I suppose that will make the bead larger too.

          It's been a long time since I used a torch for welding . . . lots of brazing, silver solder and heating . . . and I'm more than a little rusty and pretty shaky . . . used to resting my wrist on something to TIG.

          Thanks for the encouragement.
          Dynasty 300DX
          MM350P
          Hobart Handler 120
          Smith LW7 , AW1A
          Smith He/Ar gas mixer

          Comment

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