structural mig wire -help-

Date 12-28-2005 13:06

Can anyone recommend a gasless flux core or dual shield wire for general structural mild steel use. Something in .035 dia. I have a job out in the field where I will be welding light 16 gauge channels and studs for a steel structure building. The prints are pretty vague and all I can see for the light gauge field welds are:
-weld as required-
no size or spacing of weld or type of electrode is specified.
Basically just "git 'er done"
I did some research and the following Esab wires look suitable:
Dual Shield II 70 Ultra, Dual Shield II 71 Ultra, Dual Shield 70T-12, Dual Shield 7000
Are there any others that would be suitable either gasless or CO2(100%) I should probably choose a 71 series so it is all position.
I would be running a Lincoln SP 175 (220V)
Any help would be appreciated

By aevald

Date 12-29-2005 04:24

Hello Dr. D, saying that you will be welding steel studs and channels that are roughly 16 GA. and used for a structural purpose tips me off to believe that these might also be galvanized. My own experiences with this type of scenario would suggest that you go with an innershield wire to avoid problems with porosity in your welds, this may also save you a lot of prep. time in avoiding a bunch of grinding, as far as the type or brand, I would suggest any of the name brands (Lincoln, ESAB, Corex, McKay, Tri-Mark, etc.), I believe that the AWS classification is E71T-11. If you really are stuck on running a dualshield wire for this job, a really good one that runs exceptionally well on straight CO2 is Lincoln Outershield 71. Good luck and regards, aevald

By Dr. D

Date 12-29-2005 09:24

Thanks for the reply Aevald.
You are correct the studs/channels are galv. I would like to run an innershield wire with no gas since it is out in the field but don't know which one is rated structural in .035 dia.
When I was working for a shop we used to use NR211 then switched to NR232 when 211 was no longer accepted. I couldn't find NR232 in .035 so am looking for another wire. My expertise are more in SMAW & Dualshield wire in 1/16(71M). I haven't done any FCAW no gas in the field for over 5 years so just want to choose the right wire.
So what you're saying is if I use a wire rated E71T-11 then it should be fine?
Thanks again
Dr. D

By gkcwi

Date 12-29-2005 12:57

Dr. D
According to AWS D1.3-Structural Welding Code Steel- Sheet Steel, depending on the ASTM Steel Spec, you could use AWS filler metal specifications A5.20, A5.29. I know that Lincoln at least has a couple of choices that may work for your application.

Greg

By aevald

Date 12-29-2005 14:18

Hello Dr. D, I believe that the wires that are in the E71T-11 category are rated as an A5.20 as the other poster stated is a requirement of the Code. Good luck and regards, aevald One other small footnote, you mentioned that you used NR211 and then they switched to NR232 in a shop that you were working at, the reason for this may have been that the NR211 is designed for single pass welding, if you run multi-pass welds with this wire you may encounter bead cracking problems. The NR232 can be used for multi-pass welds without encountering this problem and it also has a higher deposition rate.

By Dr. D

Date 01-03-2006 11:45

Thanks for all your help. Also that makes sense about the NR-211 not being a good choice if you had to run more than one pass.
I figured I would try some Hobart Fabshield 21B. Does anyone know how well it runs, ie: any porosity?, good on galv. steel? etc.

By cfrancis (**)

Date 01-03-2006 13:34

Just my two cents. We weld a fair share of Galv. and "paint Loc" coated mild steels. I've always used Lincoln NR-152. It's an innershield that runs on DCEN . It has an extremely smooth and soft arc and very little burnthru issues,,it worked great on light guage materials.