Welding stainless (mig)

Archdukeferdinand

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Dec 27, 2006
Location
Vilas, NC
Not really a 4x4 tech question, just hoping some of the more experienced welders could give me some advice.

The valve manifolds on a couple of our snowguns have broken the tabs that attach them to the gun barrels, I want to weld the tabs back on or make a beefier set of bracketry for them.


I have a bottle of pure argon that I use for aluminum, can I use that on stainless? In searching I've found some suggestion of using 99% Ar and 1% O2, does the 1% really make a huge difference?

Also seen reference to trimix, I'd have no problem getting a bottle of that too...

Thanks in advance.
 
I've always used regular mig wire and once stainless wire with c35 when welding to stainless. Either way, it's going to lose it's stainlessness in that area. Mig welding with pure argon sucks.
 
braxton357 said:
I've always used regular mig wire and once stainless wire with c35 when welding to stainless. Either way, it's going to lose it's stainlessness in that area. Mig welding with pure argon sucks.
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I'm guessing he's using mild steel filler. Yes it will weld, but if its broke once degrading the weld pool with disimilar metals doesn't help any. Use stainless filler and pure argon for good results. A helium blend will also make the arc slightly hotter. Don't use Co2 or a Co2Ar blend. If it is 1/4 or less I would tig it. To much heat input or weld will make it that much more brittle and the rate of exspansion for stainless is 2x's that of steel, so depending on what your working with it can warp all to :poop:.
 
Here's some specifics per Lincoln procedures for GMAW semiauto welding.

Sometimes refered to as Straight Argon:

Argon+1% Oxygen Flow 35cfh _Spray arc transfer 225-325 amps 1/16 and 3/32 wire
High deposition and larger weldments use this method regularly.

Thinner material requiring smaller weldments and less heat input often use these:
1. AR+2% Ox Flow 15-20cfh short circuit transfer 85-125 amps and 15-17 volts .030 wire

2. Ar+25%Co2 "single pass welds can be made but the Co2 will affect the corrosion resistaince"
This is why we don't use it in our applications. 25% being the key.

Sometimes refered to as Argon Helium blend with no reference to the Co2:

3. Helium+7 1/2% Ar+2 1/2% Co2 "recommended for shortcircuit welding" "The gas gives the most desirable bead contour while keeping the Co2 level low enough so that it does not influence the corrosion resistance of the metal."

Tri-Mix is a trade name and may or may not contain these specific percentages of gas mixtures. Thats depends on your distributor. Most old timers and most others refer to gases by a trade name or general quote such as "straight argon" without realizing it has a small blended composition. Sorry for generalizing my first statements.
 
WARRIORWELDING said:
I'm guessing he's using mild steel filler. Yes it will weld, but if its broke once degrading the weld pool with disimilar metals doesn't help any. Use stainless filler and pure argon for good results. A helium blend will also make the arc slightly hotter. Don't use Co2 or a Co2Ar blend. If it is 1/4 or less I would tig it. To much heat input or weld will make it that much more brittle and the rate of exspansion for stainless is 2x's that of steel, so depending on what your working with it can warp all to :poop:.
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Yeah, I was planning on using stainless filler and I have a bottle of Ar and one of c25, just wanted to know if I needed a different gas.

Seems to be 2 thoughts going here. One says use stainless electrode and straight argon and the result will still be corrosion resistant.

The other says either way its losing its corrosion resistance (although now that I read it says stainless filler with c35, I can see why that'd do it).

Ultimately, I'd really like to keep the corrosion resistance. These things see water pressures up to 600 PSI and have service lives that are 20 years plus. I may just make up a different set of brackets to cradle the whole thing rather than use the tabs at all.

Thanks for the help guys.
 
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