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Mig welding pipe

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Mig welding pipe

Postby JEA » Sun Nov 05, 2017 12:04 am

Hey,

I am pretty new to welding and have been of acting laying beads down, have been getting pretty decent. Right now i am working on a project right now that i am using scrap 2" sch 40 pipe, probably wasn't the best choice but had a bunch laying around. Anyways I am having hard time having my welds look any good. When welding it does seem to wet out but the bead looks kind of big and maybe cold. I am using .030 wire, 260ipm, and 18v...the metal is I believe.154 thick. I think I should maybe crank it up a bit. I was pulling. Maybe traveling too slow. For the butt weld I had a slug in it and left a gap and the other weld was notched and had a gap as well...hope no one has nightmares from the pictures :lol:
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JEA
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Re: Mig welding pipe

Postby cj737 » Sun Nov 05, 2017 4:24 pm

Travel speed looks pretty good to me, but both welds look cold to me. Crank up the heat and see how it runs.
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Re: Mig welding pipe

Postby JEA » Sun Nov 05, 2017 5:02 pm

Any recommendations on how much I should crank it up? Was also thinking about going to .035 wire. Also would it be ok to grind it down and just reweld it. I figure won't be wasting material. Would I be able to see any pack of fusion by grinding down the weld? Thinking about grinding a ring on where the original gap was and then go at it again.

Thank you
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Re: Mig welding pipe

Postby cj737 » Sun Nov 05, 2017 9:15 pm

Cut the stem off above the weld, notch it, and weld it again. Bumping up to 0.035 wire require even more heat. For 0.030, increase your voltage half a volt and test it again. Then bump by .2v until it welds hot enough.

The best way to test the penetration is to cut a ring, then cut that into sections. Polish and etch itand inspect.
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Re: Mig welding pipe

Postby JEA » Sun Nov 05, 2017 10:35 pm

Ok I'll give it a go this coming saturday and post of pictures. In the mean time I made up a cruxiform out of some 1/4" plate and have been practicing vertical up but having a hard time not getting the puddle to drip. I have done some flat work on it. Would be able to see a heat shadow on the back be a good indicator of every running good or would that be too hot?

Thanks
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Re: Mig welding pipe

Postby JEA » Mon Nov 06, 2017 1:14 pm

Not sure it matters but found a closer up picture of one of the welds.
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Re: Mig welding pipe

Postby Poland308 » Mon Nov 06, 2017 5:32 pm

Most successful mig welds on pipe I’ve seen involved rolling the pipe as it was welded.
I have more questions than answers

Josh
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Re: Mig welding pipe

Postby JEA » Mon Nov 13, 2017 5:02 pm

Haven't had a chance to mess with it yet. It's just scrap pipe that I'm using to make a stand so nothing critical. Don't have a machine to do a roll out lol. I may just grind it down and use a 3/32" 7018 on it but I really want to to get better at wire feed processes. I've been researching settings and watched jodys video about wire speed and voltage. I compared it to a bunch of calculators such as miller and Lincoln's and they are way different. Wire speed for 1/8" thick steel. Showing 200 vs 280-300.. Seems way off for one to just be set a bit hot or even just personal preference. How do I go about this for figuring out parameters?


Thanks
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Re: Mig welding pipe

Postby Poland308 » Mon Nov 13, 2017 5:07 pm

I usually side with the time consuming method of trial and error. Adjust one setting at a time by large increments
. just so I can see what effect it has. Then turn that one back to the starting point and adjust a second one the same way. Repeat until all variables are tried, then go back to the starting point on everything, and start making small adjustments one at a time till I get the desired effects.
I have more questions than answers

Josh
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