Welding Tips and Tricks

I'm in the process of purchasing a MIG welder and so far I'm considering the Fronius TPS320i with a water-cooled torch but I'm not sure if it has enough amperage to weld different types of metal plates up to 20 mm thick.

The reason why I'm setting a 20mm thickness limit is because my plasma cutter can do a max of 20mm of mechanized cutting on a cnc table and I will eventually need to weld parts that were cut made out of steel, stainless steel and aluminum together to form a part.

I am aware that I will not be able to achieve full penetration with "only" 320A, however it is also my understanding that it is not needed on such thicknesses.

They do have higher amperage models (400,500 and 600A). However I'm not sure if these would be needed.

Any advice would be much appreciated!

It all depends upon joint configuration, spec for the weld, which has you use, position you’re welding. Will the plates be beveled? Too many variables to say definitively, but they (Fronius) are great machines.

If I were MIG/MAG welding 20mm plates, I’d be in flat position using spray transfer. Likely that would be adequate with the proper gauge wire and number of passes.

Best case scenario: Yes. Worst Case scenario: No. As CJ said, some configurations will take less amperage to weld together than others. In a "will it work in ALL cases?" type of question? I'd say no, not in a single pass with no bevel. At 20mm, you're asking to weld nearly 7/8" thick. Much bigger "no" if it's aluminum. The devil is in the details of course. If you say that you do not need complete joint penetration, then technically it's more of a "yes", but if you don't need CJP in the first place, then you are sacrificing some weld joint strength so in that case do you really need to use 20mm thick plates? Round and round we go.

drummerdimitri wrote: ↑Tue Feb 15, 2022 3:59 pm I'm in the process of purchasing a MIG welder and so far I'm considering the Fronius TPS320i with a water-cooled torch but I'm not sure if it has enough amperage to weld different types of metal plates up to 20 mm thick.

I can't add much to what cj and Oscar have said but, in general, you could weld 20mm thick material with a 320A machine but:

• You need to prepare the joint appropriately

• You will need to make multiple passes bearing in mind that some cored wires are limited in the number of passes

• As Oscar mentioned, aluminium will be problematic so say the least and may require additional equipment for MIG

And then there are the ifs and buts.

• What is the purpose of the structure (eg structural, decorative)?

• Does it need to be as strong as the material from which it is made?

• How large are the pieces to be welded and how large is the structure?

The reason why I'm setting a 20mm thickness limit is because my plasma cutter can do a max of 20mm of mechanized cutting on a cnc table

I am aware that I will not be able to achieve full penetration with "only" 320A, however it is also my understanding that it is not needed on such thicknesses.

Does this imply that the 20mm thickness is not needed for structural integrity?

and I will eventually need to weld parts that were cut made out of steel, stainless steel and aluminum together to form a part.

I assume this does not mean you want to mix materials.

If you add some more detail, I'm sure your questions will be more completely answered.

Jack

A watercooled torch hanging off a 320 amp welder is kinda cool.
Is it a new unit cause there are other products offering more amps in that price point.
For instance other than a 180 amp I use around the house and a 235 amp in the shed I have never used anything smaller than 350 ++ amps. I have cooked a torch but never to the point of needing to buy a WC unit. WC units in welding sheds are designed to work all day in the hands of production welders, if you are a Fabricator / welder you may not weld 10hrs a day and could save some cash whilst getting more amps. Besides I have worn a riggers glove under welding glove to get through a big day before
In any case 320 amps for anything other than ally would be ok. Good weld design and multipass will get spec fillets and peno no worries. You would be hard pressed to find work requiring 20mm staino, if you do hit em up for a sizeable deposit upfront and upgrade then.

cj737 wrote: ↑Tue Feb 15, 2022 5:40 pm It all depends upon joint configuration, spec for the weld, which has you use, position you’re welding. Will the plates be beveled? Too many variables to say definitively, but they (Fronius) are great machines.

If I were MIG/MAG welding 20mm plates, I’d be in flat position using spray transfer. Likely that would be adequate with the proper gauge wire and number of passes.

The plates will be beveled at such thicknesses yes.

Will most likely never need to weld aluminium or even stainless steel up to that thickness, however definitely will be doing it on steel.

drummerdimitri wrote: ↑Sun Feb 20, 2022 8:33 am

cj737 wrote: ↑Tue Feb 15, 2022 5:40 pm It all depends upon joint configuration, spec for the weld, which has you use, position you’re welding. Will the plates be beveled? Too many variables to say definitively, but they (Fronius) are great machines.

If I were MIG/MAG welding 20mm plates, I’d be in flat position using spray transfer. Likely that would be adequate with the proper gauge wire and number of passes.

The plates will be beveled at such thicknesses yes.

Will most likely never need to weld aluminium or even stainless steel up to that thickness, however definitely will be doing it on steel.

With beveling, then I'd say yes 320A will definitely do some damage to those steel plates.