Effect on tungsten electrode without shielding gas
Effect on tungsten electrode without shielding gas
(OP)
Hi all, i work for a company which is involved in welding of aluminium using TIG with Argon as a shielding gas. Square wave AC TIG welding plant is used. Today i asked the welder to disconnect the shielding gas and then try to generate an arc, he did so but the tungsten electrode started changing its colour to blackish.
What i thought was that in the absence of shielding gas, only the air in the gap between the tip and work piece is ionized hence producing oxygen and nitrogen ions but because the shielding gas is not there so oxygen oxidize the tungsten electrode. Am i right in my claim?
What i thought was that in the absence of shielding gas, only the air in the gap between the tip and work piece is ionized hence producing oxygen and nitrogen ions but because the shielding gas is not there so oxygen oxidize the tungsten electrode. Am i right in my claim?





RE: Effect on tungsten electrode without shielding gas
RE: Effect on tungsten electrode without shielding gas
Trying to quantify what's on the electrode will take more than a random guess. But the majority will be oxides of some type for sure.
RE: Effect on tungsten electrode without shielding gas
RE: Effect on tungsten electrode without shielding gas
RE: Effect on tungsten electrode without shielding gas
Well it looks like you just discovered why the shielding gas is there in the first place. The high frequency tracer will sometimes generate an arc with no gas that will not affect the electrode. However as soon as full current passes through that arc, and the electrode heats up Oxidization is immediate and inevitable. It is important to note that any shielding gas that contains oxygen in any form will have that oxygen dis-associated by the arc , with bad results to the Tungsten. A shop mistake that fortunately is not too common is putting a Mig mix of 2% oxygen/98% argon onto a Tig supply . It can drive a welder nuts for a few minutes, before he goes to find out what his helper has done.
B.E.
You are judged not by what you know, but by what you can do.
RE: Effect on tungsten electrode without shielding gas
RE: Effect on tungsten electrode without shielding gas
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RE: Effect on tungsten electrode without shielding gas
It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.