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Hydraulic tank wire/gas combination

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  • Hydraulic tank wire/gas combination

    I am trying to make a few dozen tanks to hold hydraulic oil out of HSS. I would like to use MIG since that is what I have. We are using 3 passes and still getting some porisity sometimes, causing the oil to seap through. I was hoping someone could recommend a wire/gas combination that would reduce the amount of grinding/re-welding we have to do. The HSS wall thickness is 1/4". Any suggestions?

  • #2
    What is HSS?
    Bill C
    "The more I learn about welding the more I find there is to learn..."

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    • #3
      HSS = Structural Square tubing

      I think it stands for Hollow Structural Square, but it is 4"x4" square tubing (structural steel) with a 1/4" wall thickness.

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      • #4
        Your problems may not be related to the wire and gas. 1/4" material in most cases can be welded in one pass. I suspect your problem is cleanliness. If the tanks have any oil contamination you will have porosity. You must remove all contamination completely. Please post your cleaning techniques and tomorrow morning I will address them, or someone else will today.
        Respectfully,
        Mike Sherman
        Shermans Welding

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        • #5
          Cleaning Methods

          We are grinding the area to be welded (inside and out) about an inch past where we will be welding. We also V out the area a bit to ensure good penitration. We reposition the material so that each weld is horizontal, and run two passes. Each tank has about 200 linear inches of weld, and so far each tank has had to have at least 2 repairs for porosity. We are using C25, not sure right now what wire we are using.

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          • #6
            Re: Cleaning Methods

            Originally posted by Gord
            We are grinding the area to be welded (inside and out) about an inch past where we will be welding. We also V out the area a bit to ensure good penitration. We reposition the material so that each weld is horizontal, and run two passes. Each tank has about 200 linear inches of weld, and so far each tank has had to have at least 2 repairs for porosity. We are using C25, not sure right now what wire we are using.
            2 repairs in 200 linear inches of weld is not bad...however, I would NDT the welds before you put any oil in the tanks. Once that oil gets into the pores in the weld you're sunk. Dye penetrant is the way to go...spray the dye on the inside of the tank wait for 15 minutes, then spray the developer on the outside. You'll see the flaws right away, and they will still be weldable. I would then fix the bad areas with TIG. With TIG, you can boil out the porosity very satisfactorily.

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            • #7
              Gord, clean your steel before any welding is done. Use a chemical cleaner such as acetone (put away before welding starts!). When welding is done do not test with oil. If you can test as Rocky said, fine. If not try an air pressure test. If a weld leaks and you have tested it with oil, you now have oil throughout the weld. You must then completely remove the contaminated area and start over. Do not over pressurize your tank. 50 lbs is sufficient. After applying pressure, use soapy water or a product such as "Snoop" on all seems and welds to check for leaks. If it is an open top tank and air pressure testing and dye penetrant is not possible, than leak test your tank with water. Just don't test anymore with oil. It causes too many problems when you have a leak. GTAW is a good way to repair defects, if you don't have it available GMAW will work too.
              Respectfully,
              Mike Sherman
              Shermans Welding

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              • #8
                Thanks

                Thanks for the suggestions. It is a closed tank, so I think air is a good idea for testing. I will try these ideas out. Thanks again.

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