I have a small project coming up, it will require eight welds eight inches long on 16gauge stainless. I am not likely to do much more stainless work any time soon, is it absolutely necessary to use helium/argon mix on stainless or would I be able to "make do" with pure argon on this project? I hate to rent or buy another tank of gas that will be seldom if ever used.
Thanks for the help,
Ray
Pure argon will work fine for that.
Jeff Dantzler
Helium/Argon is more commonly used for heavy or dirty aluminum.
Argon is fine for stainless steel
It is not absolutely necessary to use a special "stainless gas" when welding stainless on a casual basis.
Keep in mind... Any gas mix over 4% CO2 can jeopardise corrosion resistance to some degree.
75/25 is acceptable for single pass welds on stainless if corrosion and appearance is not paramount.Helium/argon or just straight argon can pose a problem.
Stainless steel, is indeed, a ferrous alloy. A little C02 or oxygen is needed to stabilize the arc. Straight argon on stainless welds can give us penetration problems from time to time.
I like a 97% argon and 3% CO2. Other mixes I have found to do well are..
Argon tri-mix. Usually 88 argon, 10 CO2, 2 oxy.
95 argon, 5 CO2. or something close98 argon, 2oxy-this works well, but does not ensure corrosion resistance to the fullest.Also leaves an poxidizing scale on the weldment.
Hope this helps a little!
True.
CO2 is not typically used for stainless TIG shielding gas.
Not sure what 75/25 you mean, but 75 Ar / 25 CO2 is commonly used for MIG but not TIG. There are 75/25 mixes with Ar/He or He/Ar though that would work well on stainless TIG.
Argon or Argon / Helium is the gas of choice for stainless.
Helium is commonly added to Argon to increase penetration for TIG welds on stainless. CO2 is not to the best of my knowledge.
I'm not an expert on trimixes, but I thought the gases were Ar, He, & O2 for TIG. CO2 is used in MIG gases.
Hopefully Ernie will dispel any confusion.
Jeff Dantzler
Thanks a for all the quick replies guys, I appreciate it.
Ray
My mistake... I was thinking "mig" when the question was "tig".
Anyway-straight argon, argon/helium, argon/hydrogen are all used to great effect on stainless tig welding.
In your situation, considering the thin gage material and the very occasional welding-straight argon should do all you need.
Good Luck
I was wrong here--it's hydrogen not oxygen.
Ar/He/H2 can be used to get a better color match on 300 series stainless.
The hydrogen "helps decrease the residual oxide on the weld deposit, minimizing or eliminating the need for postweld cleaning. As the thickness of the base metal increases, the hydrogen or helium content of the argon blend should increase to achieve the desired weld appearance and shape."
From a cool article "Selecting a sheilding gas for joining stainless steel" here:
Thanks!
Ray
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