Re: What gases are used in the gas shielded arc welding shielding process?

The most common gases used for gas shielded arc welding are inert gases 
Argon (Ar) and Helium (He).  It is very common to use mixtures of these 
gases, and also add other gases such as Oxygen (O2) and Carbon Dioxide 
(CO2).  I have seen some experimental mixtures that incorporated Nitrogen 
dioxide (NO2), but they are not commercially available as it is too toxic 
for domestic use.

If you want to get more information I can recommend The Welding Institute 
(http:\\www.twi.co.uk) who have online tutorials on all aspects of 
welding, and BOC Gases (http:\\www.boc.com\gases) who don't have much 
online information, but used to publish a very good information pack on 
welding gases.  You may be able to get them to send you one if it is still 
in print.

Good luck with the essay, Krystal.