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Thread: Slag Question

  1. #1

    Default Slag Question

    While stick welding Can anyone explain why the slag comes to the surface?
    I was told that the slag is less dense and for that reason it comes to the surface, my next question was, Why would it come to the surface when welding vertical or over head?


  2. #2
    Join Date
    Jan 2013
    NE Illinois


    My guess would be because the heavier metal displaces it.

  3. #3
    Join Date
    Aug 2012

    Default Slag Question

    The weld metal is electrically charged. The flux isn't. The metal is following the electric arc and trying to fuse with the base metal. The flux is pushed out of the way.

  4. #4
    Join Date
    Sep 2009


    Stick welding
    Flux come to the surface for a few reasons.
    The main reason is the flux covers the weld to shield it while cooling from nitrogen contamination from the atmosphere.
    The flux covering also help shape the weld bead while cooling.
    With some rods, the flux provides iron deposits to help increase metal deposition rate.
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