m i g . metal inert gas can any one explain what inert gas is i know its a shielding gas to protect the weld from impurities and with out you would get porosity but what is inert gas is it the same as mag welding metal active gas just wandered if any body can explain
CO2 is an active gas insomuch as it reacts with the metal slightly, but not as much as the oxygen in the air does, so it's used a cheap shielding gas. Strictly speaking when you use CO2 you are MAG welding (metal, active gas) rather than MIG (metal inert gas) as would be the case with Argon which is completely inert.
You can also use CO2/Argon mixtures, still called MIG though.
OK, you've got MIG (metal inert gas) and MAG (metal active gas).
Inert gas is gas that doesn't do chemical reactions as it's happy enough as it is already. Blow it around the weld and it displaces oxygen from the air and the weld doesn't bubble. Pure Argon is an inert gas. MIG steel with that and you get pointy welds that don't flow very well. But it is MIG welding as you are using an inert gas.
Old technology that. They figured out that if you are welding mild steel it helps to add a little carbon dioxide into the argon. Just adding a little CO2 to the Argon gives you nice rounded welds and make welding easier. The gas mix changes the weld properties so it's called an active gas. You'd be MAG welding if you used that.
There are fancier gasses developed for different applications. I'm a fan of Argoshield light (93% argon, 5% CO2 and 2% oxygen) for thin steel. Though I've tried 75% argon and 25% CO2 and no oxygen and that works much the same. For thicker steel you would increase the CO2 content and get a little more heat in there.
For terminology I call them all MIG, which strictly is incorrect (see definitions above). But then I call my vacuum cleaner a hoover even though it isn't.
so there was i welding away with my argo sheild light thinking i was mig welding when i was really mag welding, em, mag welded, sounds like i should be charging a bit more for that.
funny thing is Nitrogen is considered an inert gas, its generally non-reactive. But as i understand it during welding it can react with the metal, so it isnt just the oxygen you need to keep away from the weld its Nitrogen as well.
Helium is inert and used as a mix in Tig welding ally, not sure what would happen when used on mild steel.
Neon I also believe is considered an inert gas, i wonder what welding with that would be like, i guess it sure would look pretty and you chances of arc eye would dramatically increase as well.