dual shield with pure argon?

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The company I weld for fabricates valves for the nuclear and commercial power industry. We mainly run tig along with some stick, however some customers are starting to really push for dual shield to be used on their parts but the majority of our dual shield procedures call for the use of pure argon... We're in a little bit of a lull right now so I played with it today and man did it run like crap. I switched over to some 90% 10% and it ran better, I still think 75% 25% would be better but to run a mixed gas we would have to re qualify all our dual shield procedures on everything from groove welds to stainless and stellite overlays. Granted some of these procedures were qualified nearly 30 years ago, will it actually work with the pure argon or is that something they used to do way back?Miller Dialarc 250'61 Lincoln SA 200 Red/Blue FaceHobart Handler 175Smith O/AIf you cant dazzle 'em with brilliance, baffle 'em with B.S.!
Reply:I would look at the product spec sheet from the consumables manufacturer to see what they recommend. They specify the mechanical properties(strength, ductility etc) of the weld bead based on the recommended gases.Just for kicks I looked at a couple of spec sheets for Lincoln dual shield wires - they listed either 100% CO2 or 75 / 25 (argon / CO2).Modern welding consumables have likely come a long way in the past 30 years. It may be worthwhile to re-qualify the procedures if the manufacturer spec warrants it. The quality / productivity benefits may pay off.Regards,JasonLast edited by BCRD; 01-23-2013 at 08:07 PM.XMT 350 MPA Dynasty 280DXSuitcase 8RC / OptimaSpoolmatic 30AThermco Ar / C02 mixerAssorted O/A gear
Reply:Originally Posted by BCRDI would look at the product spec sheet from the consumables manufacturer to see what they recommend. They specify the mechanical properties(strength, ductility etc) of the weld bead based on the recommended gases.Just for kicks I looked at a couple of spec sheets for Lincoln dual shield wires - they listed either 100% CO2 or 75 / 25 (argon / CO2).Modern welding consumables have likely come a long way in the past 30 years. It may be worthwhile to re-qualify the procedures if the manufacturer spec warrants it. The quality / productivity benefits may pay off.Regards,Jason
Reply:I only use 100% co2 with my lincoln dualshield wire and I love it.Dynasty 200DXPassport plus w/ spoolmate 100victor 315c oxy/(act and prop)Miller digital elitemilwaukee power tools
Reply:I run Esab 7100 Ultra with 100% co2-good way to go. Pure argon sounds exspensive.
Reply:I weld on naval vessels with .045 and 1/16 71T1-HYN every day, and we use strictly 75/25.  I used 100% Argon once on accident and I just got a weld that was full of worm tracks and was a very dark gray.  Had to carbon arc it out and start again
Reply:I agree with everyone else I would either use 75%25% or 100% co2 on a dual shield wire. I also would use 98%2% but that was on a semi flux core cobalt wire for overlaying dies.