different types of gas

[tig trainee]

Ive ran out of pure argon and i was wondering if its ok to use argonshield universal from BOC to weld mild steel with a tig?

also is pureshield argon ok for all tig welding? i might be doing i.e mild/stainless/aluminuim/titanim?

A good article would be brilliant if i could find one to read!

 

[hotrodder]

No, can't use argoshield (or any gas containing CO2 or O2) for TIG as it kills the tungsten.

Different gas mixs offer benefits in certain applications but pure argon is suitable for TIG welding any alloy that's weldable and is usually the most cost effective

Helium increases arc heat but is harder to 'ignite'. Typically used as a mix with argon for welding thicker sections of aluminium for increased efficiency (higher welding speeds)

Argon + small amount hydrogen (2 - 5% typically) is sometimes used for stainless and nickel alloys- the addition of hydrogen creates a 'reducing atmosphere' which improves shielding quality with respect to oxidation. Also increases arc heat and 'tightens' the arc allowing faster welding speeds

Tiny amounts of nitrogen can be added to argon for certain applications. Not sure on all the details as nitrogen can effect the tungsten but i believe it can be beneficial for duplex stainless- something to do with altering the austentite content. Nitrogen can be used for purging stainless in some cases

 

[tig trainee]

Thanks very much.

I have just found the miller site and its briliant to say the least.

 

[hotrodder]

yep, lots of info there. The TWI has plenty of articles too, as does thefabricator.com