Welding Critique

[philbar715]

I am a new welder. I was wondering if what I am seeing below is normal? Im using 100% c02, probably around 25cfh, maybe slightly higher and .030 wire (I used lincoln and harbor freight wire both with the same results) which makes me think its something that im doing.

Basically im seeing a grey slag like finish on the outside of the welds. very similar to what you get when using flux core wire. It seems to chip off all on its own as the weld and steel cool. If I scratch it off with a screw driver or pick or something sharp, it only makes a scratch and doesnt quite peel off like what it does on its own when its cooling. Once its cooled, if I hit it with a wire wheel it doesnt really come off, just makes it slightly shiny. Ive attached two photos. One with the circles outlines the areas in question and the other is of the piece overall.

Its bent because I hit it with a hammer and tried to break it (to test the strength).

 

[strength_and_power]

Right off the bat, I’d say your gas flow is way too high, 10-15cfh would be better.
What kind of welder? What wire speed? Material thickness? Voltage setting?


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[philbar715]

Right off the bat, I’d say your gas flow is way too high, 10-15cfh would be better.
What kind of welder? What wire speed? Material thickness? Voltage setting?


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Its a no name brand inverter welder from china. Wire speed was around 250ipm, and around 20.5v. Inductance was set to -10 (on a scale of -10 to 10, default is 0). Adjusting the inductance only made the bead flatter or taller. Steel thickness was about 2.65mm. Thanks for the suggestion on the gas, I'll turn it down and see if that changes anything. I got the settings I used from this chart;

https://app.aws.org/mwf/attachments//25/253025/parameters.jpg

 

[kb1982]

It looks like a gas coverage issue to me. Assuming your mig welding, 25 to 30 should be fine. Check the condition of your nozzle and make sure its not covered in boogers and splatter messing with the gas shielding.

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[dr_clyde]

Its hard to tell from just one picture, but those appear to be silicon deposits. They look and act like glass.

You're probably using an S-6 wire, which has a higher level of silicon in it for removing oxides and other contaminants from the weld pool. When you weld on dirty or scaly steel, those deposits will float to the top of the weld pool and solidify.

I can see you're welding on steel with scale on it. I can see it cracking off and flaking. I would grind your metal to bare shiny steel and try again. You will be surprised how much nicer the weld flows.

And I would turn my shielding gas down just a touch. Too high shielding flow and you risk pulling in atmosphere with a venturi effect. 15-20 is plenty for what you are doing.

 

[koditten]

Any chance you were using flux core wire previously? Did you remember to switch the polarity?

 

[dffay]

MIG mix is typically 75/25 CO2/Argon. I suspect that 100 percent CO2 is incorrect. And, the gas pressure is too high anyway. Perhaps 18-20 would be more gentle to the blow out effect I think I can see in the weld to the right side of the photo.

 

[dffay]

75 Argon / 25 CO2 I should have written....

 

[dr_clyde]

100% co2 is an acceptable sheilding gas for MIG. Not as smooth as C25 but acceptable.

I don't believe this is a shielding issue. There is no porosity present.

I'm confident that those are silicon deposits.

Just clean the base metal and they will mostly go away.

 

[bdbecker]

...I'm confident that those are silicon deposits. Just clean the base metal and they will mostly go away.

I think you are spot on. The second pic is the one titled "capture.jpg" and isn't embedded into the original post, but it has the the circled areas the OP mentions in his post. In that pic, the circled areas certainly look like silicon spots.

 

[MoonRise]

Pure CO2 is an acceptable shielding gas for GMAW (aka MIG) in the short-circuit transfer mode.

It run a little 'hotter' than C25 (25% CO2 and 75% argon) and can give a little more spatter than C25 too.

But that has nothing to do with the OP's question.

Agree with dr clyde (aka Jake ) that from one picture over the Net that is looks like normal silicon island slag from the silicon that is in the ER70S-6 wire. A rather lot of slag for a MIG weld IMHO, but still just silicon slag.

And a wire wheel on an angle grinder should be able to remove that slag and leave you with bare clean shiny weld beads.

And a +183 on remove the mill scale from the material BEFORE you weld, as you will ALWAYS get a better weld if you are welding clean shiny metal and not anything that is NOT clean shiny metal (like rust, or mill scale, or paint, or grease, or oil, or dirt, or possum guts, or whatever).

 

[philbar715]

thanks for all of the suggestions! I adjusted the gas and made sure it was set a little above 20cfh. I cleaned most of the mill scale off of these pieces I welded today, then took a wire brush to one section to see how it looked. Pics are attached. (this is of a welding cart im building) In one of the photos, it looks like there is porosity but its just some deposits on the weld that I brushed off with brush.