Recently this question has been asked by some people and we believe it is appropriate to give a detailed explanation of the answer because we too thanks to this research we understood more things than before, and now we would like to share them.
The argon is an inert gas used in welding. An inert atmosphere is necessary in welding to defend the molten metal from the inclusion of:
- Hydrocarbons
- oxygen
- humidity
All three are variables that can bring welding to have defects most of the irreparable times.
Why is it used Argon and not nitrogen, which is another inert gas and is it even less expensive? Because Argon is a noble gas and maintains its properties even at high temperatures, while high temperature nitrogen creates "nitriding", a word that means "oxidation". In short, nitrogen cannot be used to weld.
Furthermore, we use the Argon because it has a great power of ionization, that is, it helps the passage of the electric arc into the inert atmosphere. The more the ionization potential is high and less I will need energy.
And now we return to our initial question.
When we welcome MIG / MAG wire, we can weld with 100% pure argon, but the bathroom would be quite cold and would become less penetrated, almost always gluing the pieces without really welding them.
Why do we also use CO2 so? Because so welding will be warmer and will enter more penetration.
The siad, ours Partner for the distribution of technical gases, it recommends a mixture 92% argon + 8% CO2 on carbon steel below 4 mm thick, while for thicknesses greater than the 4mm of carbon steel it is better to switch to mixture 82% argon + 18% CO2.
On the stainless steel the situation is a bit different. Stainless steel (stainless steel) is a metal that in addition to iron also contains chromium, nickel and molybdenum, which make it not susceptible to oxidation.
To allow stainless steel not to lose its characteristics it will be better to lower the CO2 percentage contained in the mixture. Below 3% the stainlessness of the steel is guaranteed. Usually a 98% argon mixture + 2% CO2 is used to weld to stainless steel.
It is never really possible to weld steel in mig with pure argon?
For charity, if you are hobbyists and you have arrived at the end of the Argon + CO2 mixture cylinder or if you simply wanted to try to weld wire but you only have pure argon then there is no absolute prohibition to use the argon pure, we are Even in democracy! You can do it, but conscious of everything that has been said above!
What metals can be welded with 100% argon in mig?
- Aluminum
- Copper
- magnesium
- titanium
As always, for any questions, clarification or to signal the inaccuracies write us! You can do it on:
- Whatsapp: 348 6018421
- Email: info@tecnista.it
1 comment
matteo gasperoni
Salve,..sto iniziando adesso a saldare da hobbista…volevo chiedervi una informazione….si puo saldare a filo con la bombola di solo CO2 ? sapevo che in genere si usa la miscela con AR al circa al 18.
in quale caso si usa solo CO2 ?
grazie
saluti
Matteo