What is TAG Welding? These guys seriously know what they are talking about. Or do they?!
Q. What is TAG welding?
A1. TAG stands for Tungsten Active Gas and is a recent modification to the name TIG, Tungsten Inert Gas, but as far as we can see there is no difference between the two methods. It seems to be following the idea that MAG is differentiated from MIG. MAG is used when the gas contains oxygen or carbon dioxide because the gases are not truly inert. However, this distinction is not clear for TAG so we suggest you stay with convention and call the process TIG (or GTAW if you prefer the American term).
A2. Yes indeed TAG is Tungsten Active Gas. But is not using gases with O2 & CO2 in. Its mixed gases which are active an not Inert.
The most common Active Gases for TIG are Argon/Hydrogen or Argon/Helium.
In Argon/Hydrogen gases the gas becomes reducing and there for is no longer inert. By ‘reducing’ we mean that during welding the hydrogen in the gas attracts and combines with the oxygen and therefore ‘reduces’ the oxygen in the atmosphere.
A3. I agree with Steve’s comment on hydrogen but I must be an ‘anorak’ and point out that he also included argon/helium as ‘active’ when both gases appear in the Periodic Table as Inert Gases.
Hydrogen is chemically very active and does reduce oxygen, and indeed oxides, but the main effect a welder will see is that it makes the arc ‘hotter’. That is, you get better penetration and metal flow. This also happens with argon helium mixtures so these are becoming increasingly popular TIG shielding gases. They do not however have any chemical activity so the process is still TIG.
Thus it is technically correct to call argon/hydrogen ‘TAG’, but not argon/helium. It doesn’t seem to me that the differentiation between TIG and TAG is serving any useful purpose so I should like to see things stay simple and the process remain ‘good ol’ TIG’.
A4. Sorry Dr Weld was not aware helium was inert. But them I am no chemist!
I always consider the helium mixed gases as active because of the increased arc force, but maybe this is my mis-interprication.
And I agree lets forget TAGS and keep to TIG.
A5. Although quite a rarity TAG welding of certain ally alloys is becoming more common, a small amount of oxygen (about 0.03%) is added to either argon or argon helium mixtures, the result is a “tighter” arc and improved weld quality and appearance.
The comments about argon/helium mixtures being inert are correct, although helium additions to argon make a big difference in weld quality, deposition rates etc the mixture is still inert.
A6. thought the AG in MAG + TAG meant agitated not active. Adgitated meaning a mixture of gasses and not pure, eg Argon TIG, Argon+Helium TAG. Different process but the same with MIG.
A7. T.A.G (TUNGSTERN ACTIVE GAS) = Any gas or combination of gas/gases that have a beneficial effect on the weld/weld characateristics’.
Helium has an effect on weld characateristics =Hotter arc!
Hydrogen has an effect on weld characateristics=Hotter arc!
Oxygen has an effect on weld characateristics=better ‘wetting’of the parent material.
Active refers to the ‘BENEFICIAL’ effect the ‘Gas’ has on any given weld/material!
Not whether the gas is ‘active’ or not!
A8. Everybodys wrong it’s a simple spelling mistake T(I)G!
Once again Ha! Ha! and so the saga continues.
As welding equipment suppliers – we know all there is to know about welding machines BUT if you need some serious advice on How to Weld, we suggest you look at the forums out there. UKwelder.com and mig-welding.co.uk are both informative, light and full of lots of advice (not all useful) on welding procedures and applications.