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Craters with 71m dual shield wire

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Craters with 71m dual shield wire

Postby Bkdsherrod » Tue Feb 28, 2017 12:42 pm

I'm new to dual shield and I watched all of your videos and decided to give it a try. I'm using lincoln 71M .035" DCEP using a Miller 250X Ar/CO2 mix@ 30 cfh. Overall I am pleased with results. I am however getting small Jalapeno-shaped craters when I knock off the slag. I've found increasing the gas flow significantly reduces the number of craters, but it doesn't totally eliminate the problem. The weld itself is sound, with no visible porosity - these are small surface imperfections about 1/8" long. Has anyone else experienced this?
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Re: Craters with 71m dual shield wire

Postby MinnesotaDave » Tue Feb 28, 2017 8:59 pm

I don't know if it matters to your specific problem, but the literature lists shielding gas flow at 40-50 CFH.
Last edited by MinnesotaDave on Tue Feb 28, 2017 9:39 pm, edited 1 time in total.
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Re: Craters with 71m dual shield wire

Postby Farmwelding » Tue Feb 28, 2017 9:02 pm

Just be careful with turning up the gas. Don't go so high that the gas flow blows wagon wheel tracks in your welds. Like anywhere past 50-60 CFH will start blowing out metal. Watch some more videos and watch the angles they use. Your gas may be having issues based in gun angle too.
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Re: Craters with 71m dual shield wire

Postby jg21184 » Wed Mar 15, 2017 11:27 pm

I also experience this problem from time to time. I have been told they are called worm cracks and they drive me crazy. I can run a good clean weld one minute and the next weld will be full of these imperfections. My wire is good clean wire, metal is clean and gas flow and coverage is good. What else can i do to prevent this.
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Re: Craters (worm tracks) with 71M dual-shield flux core wi

Postby Bkdsherrod » Wed Mar 22, 2017 4:43 pm

I did try increasing the shielding gas flow up to about 45 CFH and this did result in fewer "worm tracks" but it didn't totally eliminate them. I am using .035 lincoln 71M with 75/25% mix. The worm tracks don't appear to be associated with any type of porosity in the weld, but rather miniature Jalapeno-shaped depressions randomly spaced on the top of the weld bead.
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Re: Craters with 71m dual shield wire

Postby Farmwelding » Wed Mar 22, 2017 5:20 pm

Is there any contaminants on the base plates? If the truck that carried the steel passed through on a winter storm and coated in salt or something like that, it could have a lot of contaminants causing porosity. What cleaning are you doing?
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Re: Craters with 71m dual shield wire

Postby weldin mike 27 » Thu Mar 23, 2017 4:09 am

This is caused by too much voltage. Crank up the wire speed.

It doesn't seem right, but thats it. We call it worm tracks.
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