Hello, I work in a shop that welds a lot of light gage stainless,( 18ga.-10 ga. )with the GMAW process, and we have always used the tri-mix, 90 He,7.5 Ar, 2.5 Co2. Could anyone tell me if there are other gas mixtures that might work just as good or better? And maybe more cost effective. Can 75 AR-25 Co2 be used on these light gages without any adverse effects? Also, we use pure Argon for all our GTAW on stainless, has anyone used a hydrogen-argon mixture for this process on light gage stainless described above? Thank you to anyone who can help straighten me out.
I haven't had a chance to try it, but Ed Craig of http://www.weldreality.com/ recommends a 97 AR - 3 Co2 mix be used for Stainless vice the popular Tri-Mix. His arguments are quite compelling towards using the lower energy AR versus He. Although light gauge stainless can be welded with 75 AR - 25 Co2, the mix can be problematic in that you are introducing a large concentration of Carbon into the Stainless which can lead to cracking.
contact your local gas supplier and get some gas for demo
98/2 co2 works well and u can use 100 percent arg.
A while back we were using GMAW with 100% Argon to weld some SS 304 10 gage sheet. I was not happy with the results as the bead always came out rough looking with poor penetration and didn't wet well along the edges.
We wound up switching over to flux core with 90% Argon and 10% CO2 which performed much better.
I haven't tried the FCAW on 18 gage yet.
Good Luck!
Tim
hi, the shop i work in we have been welding our ss304&316 with a hydrogen mix it ,i believe it is 1%hydrogen ,3%co2 & 96% argon and it weld very well! , especially with pulse transfer, thepulse has verynice color almost like gtaw. there is also a mix with 3%hydrogen but we have not tried it yet(haven't needed to). it also welds good on spray .
good luck,
mike wright
I you are interested in a flux cored wire , Kobelco's dwg wire is great on 10ga.ss. Kobelco advertises in the WELDING JOURNAL and we got a spool to try and it does weld as good as they claim. ( we used75/25)
mike wright
I use 98Ar/2 oxygen and it works great. Much more stable arc than 100% Argon. I also use 95Ar/5co2 for other applications. I ran some tests using the Tri mix you mentions but seen no real advantages. As n5 says get a bottle of 98/2 and give it a try.
kam
Hi mikec
In our part of the world, we generally use Ar 2%O2 to weld stainless with the GMAW process. (As was recommended by Kam) While low percentages of CO2 in Ar (e.g. 3%) is sometimes used, you must never use a high percentage of CO2 to weld stainless.
I have no experience with adding H2 to GTAW shielding gas. The only gasses I have experience with are Ar(Mostly used) and He(Used when higher energy arc is required.)
Hope this helps
Regards
Niekie Jooste
Fabristruct Solutions
What transfer mode of GMAW are you attempting to achieve? Shielding gas will be a huge factor in being able to achieve it. Keep the CO2 as low as possible to eliminate carbide precipitation. Don't just factor in the cylinder cost per cubic foot but also advantages such as ease of setting parameters and clean up costs. I don't sell gas but I know an expensive up front gas can save a lot of time and money in the end. Visit a couple of gas sales persons and sample their product for what you want to do. Factor in all the costs and then make your decision.
C02 content below 4% or so with the balance argon has no detrimental effect on stainless welding.
You will find tha that a hi argon/lo C02 mix will work very well on the thinner gauge stainless.Much better than hi argon with oxygen.
97 argon/3C02 works very well for me and a number of shops I am aquainted with. Will short arc and spray.
The hi helium mixes seem to put an additional amount of heat into the weld, which in the case of thin gauge, is not always welcome.
How did I come up with this mix??
No, I am not clairvoyent or have a crystal ball.
I have read a number of Ed Craig's books, however.
Any questions, let me know...
Good Luck
Brande
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