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Thread: I Must Have Got Behind In MIG Welding Technology

  1. #31
    Join Date
    Oct 2005
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    British Columbia
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    6,707

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    Quote Originally Posted by Doozer View Post
    That does not make any sense.
    What physical or chemical phenomenon makes oxygen in the gas mix
    make for a higher temperature and smoother flowing puddle
    while not affecting the weld pool and make it oxidize and bubble up to high heck?

    -Doozer
    A very small proportion of the mix is oxygen, just enough to achieve the desirable results but not enough to oxidize the metal to the point that it actually burns the weld pool.


    https://www.thefabricator.com/articl...ding-gas-mixes

    Argon/Oxygen. Adding small amounts of oxygen, normally 1 to 5 percent, to argon greatly stabilizes the welding arc, increases the filler metal droplet rate, lowers the spray transition current, and influences bead shape. The weld pool is more fluid and stays molten longer, allowing the metal to flow out toward the weld toes.

    Adding 1 percent oxygen to argon produces a blend used primarily for spray transfer on stainless steel. This amount of oxygen usually is sufficient to stabilize the arc and improve the droplet rate and bead appearance.
    When 2 percent oxygen is added to argon, it produces a blend suitable for spray arc welding of carbon steels, low-alloy steels, and stainless steels. It provides greater wetting action than the 1 percent oxygen mixture. The weld mechanical properties and corrosion resistance of welds made with 1 percent and 2 percent oxygen additions are similar. However, bead appearance will be darker and more oxidized for the 2 percent blends with stainless steels.
    Five percent oxygen mixed with argon produces a blend that provides a more fluid but controllable weld pool. It is the most commonly used argon/oxygen mixture for general carbon steel welding. The additional oxygen also permits higher travel speeds.

    Home, down in the valley behind the Red Angus
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  2. #32
    Join Date
    Jan 2009
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    WV
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    Quote Originally Posted by JoeLee View Post
    Never heard of 98 2.

    JL..................
    I have a bottle to help get in to spray.

    Last edited by Ridgerunner; 05-13-2019 at 07:14 PM.

  3. #33
    Join Date
    Dec 2008
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    The Four Flags City
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    Quote Originally Posted by JoeLee View Post
    I also have wondered do they evacuate these bottles before re-filling?? I'm talking a bottle being re-filled with the same gas. I would think that if a bottle was to be filled with a different type of gas or mix that the it would be evacuated to remove any traces of different gasses left or any impurities.

    JL................
    Unless you’re cutting corners the process is vent, vacuum and fill.

  4. #34
    Join Date
    Jul 2017
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    13

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    Quote Originally Posted by BigMike782 View Post
    Lowwe.Buuck, if you sourced a tri mix for stainless and you got the correct gas it would be helium/argon/CO2. The argon mix discussed above has too much CO2 to work correctly on SS.
    It was late and I meant SC (short-circuit) and spray transfer. Good catch.

  5. #35
    Join Date
    Aug 2006
    Location
    Beaverton, OR
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    8,527

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    Quote Originally Posted by JoeLee View Post
    I also have wondered do they evacuate these bottles before re-filling?? I'm talking a bottle being re-filled with the same gas. I would think that if a bottle was to be filled with a different type of gas or mix that the it would be evacuated to remove any traces of different gasses left or any impurities.

    JL................
    Yes, they do.

  6. #36
    3 Phase Lightbulb Guest

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    I've always used C25 for Mig and 100% Argon for TIG.

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