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Flux Core Welding Myths Debunked

Discussion in 'The Tool Shed' started by ITLKSEZ, Mar 3, 2020.

  1. Mar 3, 2020
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
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    A great video for flux core welding tips.

     
    DirtRoad61, garage gnome and FinoCJ like this.
  2. Mar 3, 2020
    Bigdaddy13

    Bigdaddy13 Member

    So.Cal
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    Wow, great info! Thanks for posting.
     
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  3. Mar 3, 2020
    Focker

    Focker That's a terrible idea...What time? Staff Member

    WA
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    Thanks for posting.
     
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  4. Mar 4, 2020
    jeepermc

    jeepermc Active Member

    Western WA
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    Good link. Been welding awhile, but still learning basics through trial and error alot. lol
     
  5. Mar 4, 2020
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
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    From the video, it would seem I am definitely not using enough wire stickout....
     
  6. Mar 4, 2020
    garage gnome

    garage gnome ECJ5 welder

    Western MA
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    That was informative. For structural welding (buildings) , arc and flux core with gas are the only two acceptable methods if anyone is interested.
     
  7. Mar 4, 2020
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
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    The weld process should be specified in the prints for each particular job. The process is decided by the engineer/architect. I’ve run countless miles of bare MIG wire at my time as an iron worker. Most prints only specify “70xx.” As long as the wire or rod is rated at 70,000 psi, the actual process is unlimited unless specified.

    “A welding procedure specification (WPS) provides detail welding conditions for a specific application containing the essential variables that require requalification of procedures when the variables are changed beyond specified limits. Typical weld procedures should, at a minimum, contain information about the base materials that are to be welded, the welding process, the filler metal designation, type of current and range, arc voltage and travel speed, joint design and tolerances, surface preparation, positions of welding, preheat and interpass temperatures, interpass cleaning and post weld heat treat as needed.”

    Source: https://app.aws.org/files/199/622219/welding_procedure.pdf
     
  8. Mar 4, 2020
    garage gnome

    garage gnome ECJ5 welder

    Western MA
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    That’s what my welder friends told me when I started to get into structural welding. Mig is fine to tack things in place, but then the tacks have to be feathered out and the joint has to be arc welded or flux core welded. I’m about to get my structural welding license and the test is done with an arc welder using 7018 rod. I’d like to get my pipe welding certification too and that’s done with arc using 6010 for the root and 7018 for the cover passes. You can see in this video how the mig didn’t penetrate as much as the flux core.
     
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  9. Mar 4, 2020
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
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    *at equal voltage.

    If not limited by voltage, with a 600 amp power unit, you could melt a hole through 1/2” plate with a mig with .052 wire if you’re not careful.
     
    Last edited: Mar 5, 2020
    73 cj5 likes this.
  10. Mar 5, 2020
    BadGoat

    BadGoat How High Can You Climb?

    Northern Virginia
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    Stick and flux core are used because they are easy to use outside and the production rates are good. As an oil & gas maintenance supervisor/project manager, we don't dictate the welding process to our contractors (structural, pipe, and others), they own their own welding procedures. We simply dictate the final strength requirements and material properties. This puts the quality on the contractor as if the weld fails during QC/QA, then it's on their nickle to fix it. Whereas if the owner dictates the procedure and the weld fails, then the owner has to pay to have it redone assuming the procedure was followed. There is a fairly involved testing process for their weld procedures including dye penetrant, x-ray, and bend tests depending on the application. Once the procedure is approved, they then need to test each welder against the procedure to ensure that they can perform it properly. We also use so many different types of metals (from carbon steel to exotic stainless alloys and more), that no single method could begin to cover it.

    Mike
     
  11. Mar 10, 2020
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
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    Used my welder yesterday....I checked for correct polarity (in this case I was using flux core) - which it was - and also noticed that the 'directions' on the welder also pointed out the difference in the wire feed rollers. So I verified that it was all good for flux core. So, that left using a bit more wire stick-out....and I think it helped! Much less porosity and a smoother bead. It was a quick, small job that I didn't really do any testing for, and I think I needed a bit more voltage (or maybe less wire speed), but hey, it was step in the right direction. Thanks!....as a side note/question...in a situation like this, I am not always sure when I should increase voltage vs when I should use less wire speed. I felt the beads were too 'tall' (if that makes sense - it took some grinding to get them flat which they needed to be in this case). The penetration seemed ok, but maybe it wasn't. I don't like to move too fast, and I want to see the pool develop, so I feel like I default to slower wire feed so as not to add to much weld....Often, the instruments recommended settings for flux core have a wire speed of 5 (on a 1-10 dial, and different voltage of course for gauge), but I always feel like its coming out a bit too fast for me.
     
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  12. Mar 10, 2020
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
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    If you’re getting a tall weld, you can try turning down the wire speed, but what’s most important is to look at the sides of the weld. A tall bulbous weld is often a sign of low heat, where the weld is just sitting on the workpiece with poor penetration. If the edges of the weld are at a sharp angle to the workpiece with a definitive angle (a telltale sign is when flux sticks in the corners and is hard to remove), more heat is headed. If the sides are flowing smoothly into the workpiece, your heat is probably ok, and you can afford to back off on the wire speed.

    A good judge of heat is to look at the underside of the workpiece. Deep penetration will show discoloration or even oxidization underneath. If you’re getting visible signs of heat underneath, your voltage is probably adequate, and you can turn back the wire speed if needed.

    Found this. These looks like stick welds, but similar principle.

    [​IMG]
     
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