Limits of Work PieceThickness Using MIG

[Cgotto6]

Yes, it is as good if you are doing a groove joint. Doesn't work with fillets. Just takes more passes, which is harder to control.

[Jimmydoc1]

Maybe the final answer was given and I just didn't get it, but i'm still wondering if you can weld thicker materials by making a vee and just using multiple passes. Of course, it can be done but what would the strength be like?
I have a mm212, which is rated for 3/8 in a single pass. If I were to make a vee on both sides and make multiple passes, would that be as good as using a machine rated for 1/2?
Jimmydoc

[Sandy]

True... The .023 data was extrapolated based on the charts in the back showing current vs. wire feed speed. They all start at .030 (that should tell you enough just based on that) but a reasonable look will give you an idea where .023 runs...

Yeh the .023/.025 would occupy a space at the far left of that chart, pretty much starting at about 25-30 amps and going straight up by 100 amps. A guy might squeak a tad more out of it by setting the feed speed on WFO. Not much tho.

I doubt .023 was developed with occupying a significant range of amperages on a chart. Kind of a 'do it all' wire. That would be nice.

[johnnyg340]

Check or down load the GMAW hand book at this link. About page 16. Search for 'current density (saturation). Notice on the one graph .023 isn't even part of the example.

http://www.lincolnelectric.com/asset...L-56/c4200.pdf

True... The .023 data was extrapolated based on the charts in the back showing current vs. wire feed speed. They all start at .030 (that should tell you enough just based on that) but a reasonable look will give you an idea where .023 runs...

[elvis]

I don't know the technical details of wire size to weld output but my experience is that it is silly to consider using .023 wire for anything over 1/8th thick parent material. To argue otherwise is silly and flies in the face of all the welding disciplines.

You should probably run at least 300 amps through your 3/32 smaw electrode or weld 1/2" aluminum with 040 tungsten. That will yield the best penetration at the smallest part of the duty cycle of the machine.

I was using a mm175 w/ .030 er70 wire at work the other day to weld on 3/8" drag chain for a forestry mastication attachment. I kept hitting the friggen duty cycle of that little machine. What a pain.

[Sandy]

Check or down load the GMAW hand book at this link. About page 16. Search for 'current density (saturation). Notice on the one graph .023 isn't even part of the example.

http://www.lincolnelectric.com/asset...L-56/c4200.pdf

[Cgotto6]

I see what you are saying. The person who explained all of this to me must have left out that there are limitations on the high end of amperage a specific wire can take. But if within those constraints, you could interchange wire size and just adjust the feed rate to achieve the same weld output. Thanks for the explanation.

[johnnyg340]

Hey jonny I haven't heard of current saturation before. Where did you learn this, I would like to check it out. Thanks

MEANT TO REFERENCE THE ABOVE QUOTE... MY BAD. I don't post often...

[johnnyg340]

Also, i don't remember the exact equations but joules measure the energy input into the steel. Just because you have to crank .023 to weld the same thickness material as .030 at about 2/3 of the .023 WFS DOES NOT MEAN you are putting in a hotter weld (energy measured by joules)

Hate to say it here, but it's in Lincoln's GMAW welding guide. This of why you would never run 14-2 wire for a 120v 40amp circuit in your house. Current is volume, and the conductor size (14ga for home or .023 .030 etc... for welding) must be able to handle the load. The voltage is simply the pressure to push the load.

[johnnyg340]

Also, i don't remember the exact equations but joules measure the energy input into the steel. Just because you have to crank .023 to weld the same thickness material as .030 at about 2/3 of the .023 WFS DOES NOT MEAN you are putting in a hotter weld (energy measured by joules)

[Cgotto6]

Hey jonny I haven't heard of current saturation before. Where did you learn this, I would like to check it out. Thanks

[johnnyg340]

Guys,

Look at the current saturation point for .023 wire. Somewhere around 150 amps the wire is current saturated and you will not squeeze and more out of it because of the conductor size .023. In fact, .030 still won't do the job, as it gets saturated at about 190 amps or so. So, no matter how high you crank the WFS and voltage on the machine, you will not get the energy out of these wires for 5/16. A weld on 5/16 steel will require in the neighborhood of 200-210 amps. .035 wire is the way to go, and even with that the 180 machine is at it's limit.

[Cgotto6]

also you say the weld is gonna require the same voltage reguardless of wire size that doesn't make sense .if i have my machine set for .030 and drop a roll of .023 in it it's gonna burn hotter than it was with the .030. so i will have to turn the amperage down to weld.

No it won't, if you actually set it up properly, you wouldn't need to do anything other than turn up your feed rate to compensate for the smaller volume of wire per inch. In the end this would result in a weld of the same amperage and voltage.

[Cgotto6]

Tommy what you are describing in your instances is due to your machine having no horsepower. What I described is the reality. Saying a specific size wire burns hotter is not true. What I said in my last post is how it is. There is a set ratio of wire volume entering the weld and amperage of the weld. You can achieve the same wire volume with different wire sizes by adjusting the feed rate.

I don't doubt your 140 won't run .030, but that absolutely nothing to do with this situation. It has to do with your machine not having enough power to burn that volume of wire. Keep in mind everything you have said relates to your experiences with your little 120v mig, and nothing to do with the OP's question or situation.

[tommy2069]

also you say the weld is gonna require the same voltage reguardless of wire size that doesn't make sense .if i have my machine set for .030 and drop a roll of .023 in it it's gonna burn hotter than it was with the .030. so i will have to turn the amperage down to weld.