c-25 or c-8 is one better than the other

Date 02-03-2004 03:56

we use carbon dioxide @25% balance argon for welding o-lets on sch.10 and sch.40 mild steel pipe. We also fabricate some shop welded fittings and flange pipe. We use er70s-6 wire in .035 and .045 diam. I was wondering if i would get a better weld using cd-8 and ar mix?deeper penetration and weld apperance,performance? i was told this was a better mix . What do u all think? thanks for your time and advice

By sparx

Date 02-03-2004 13:30

C-8 will allow you to spray transfer whereas the c-25 won't. weldor appeal and bead profiles will look nicer with the c-8. another option that is often recommended as a gas for all welding (steel of course) is c-15. great for spray transfer, great for short circuit. (Liquid Carbonic used to sell Metal Match Steel, which was C-17. Praxair produces this gas under the stargold c-17) another good choice for all steel welding.

By dee

Date 02-03-2004 20:18

Out-of-position issues with pipe may make spray impractical or impossible to actually utilize. You have a "cold" mixed gas that will minimize burn-through problems but presents some fusion issues in short-arc due to low arc energy and narrow penetration profile. I agree with sparx in general and specifically about c17; I use a c12 mix, but the filler you use will be also be an issue with the final result; stick to the 035 I believe... lots of data here:

http://www.weldreality.com

as you are probably aware, the more CO2 in the mix or the larger the electrode diameter, the more energy in the weld & the more risk of burn-through on thin stock and the faster you need to travel... if you can limit your weld to flat or vdown you might attain a potential in the realm an inch of weld (not filler wire speed) per SECOND in spray... c8 might be good for that but as you will see may slow down your rate of production by several inches per yard..