Welding: TIG vs. Gas

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What are the pros and cons of welding 4130 with tig or gas? There seems to be alot of controversy on stress relieving etc.
Thanks John

The Tin Man Respondeth:

John, Briefly stated are the following pros and cons on Tig vs Gas on 4130:

Gas will enter into a narrower angle.
TIG may use a little less rod.
Gas headgear is smaller, enabling head entry through tight spots.
The postweld gas flow from TIG can quench and harden the weld, whereas the gas torch may be played over the weld for a moment after welding, to enable stress relief.
TIG can encourage the use of insufficient filler. Trying to make the daintiest appearance welds is actually detrimental to weld strength. This is something a torch guy is less tempted to do since it goes against the natural welding process of the gas torch.
The gas torch is less expensive to buy and operate.
It can be used for brazing, soldering, annealing, bending, and forming - which the TIG cannot.
And...in a breezy hangar, shop, or out doors the torch is unaffected by 30 MPH gusts. The TIG's delicate inert gas envelope, on the other hand, is adversely affected even by sighs of relief.

And for other alloys: For perfect penetration on aluminums and stainless, the TIG requires a complete argon backpurge, or at least a backup flux. The gas torch, on the other hand, uses a flux and makes a flatter bead with perfect penetration anyway.

Kent White

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