I suggest going to the web sites of the manufacturers to see what they have to say. They typically provide information about the advantages of each of the filler metals they produce.
Point of information. The AWS committee on filler metals is in the process of removing the cored electrodes from the GMAW filler metal specifications and moving them to the FCAW filler metal specifications (carbon steel and low alloy steels). The F numbers will not be affected by this change.
From a personal viewpoint, I could never understand why the cored electrodes were included in the GMAW filler metal specifications to begin with. Then again, I am not knowledgeable of the history behind why they were grouped as they are and I'm sure those decisions have lots of history.
Best regards - Al
I'd have to do some research wire types etc. to give you an accurate answer but in my experience the flux core is not as strong. I used to work for an outfit that did a lot of heavy equipment repair and the only thing they would let us use the flux core on was the belly dump skins, boxes etc. They did not want us using it for bumpers, frame repairs etc. one day I asked the owner about it and he walked me over to the table and had me make 2 welds on 3/8 plate flat fillets. One was with external shielding and one was inner shield (Flux core) after they cooled off I broke both welds with a sledgehammer and the flux core one broke significantly easier. I also seem to remember the penetration was better on the metal core weld. We were using .035 inner shield then and I've used it on a lot of stuff since which I have had no problems with but on higher stress items I usually will use stick or tig anyways. Check with some heavy equipment shops in your area and see what they recommend because that stuff takes a beating and if it's holding up for them that is what you want IMHO. Flux core is definitely more cost effective supply wise and in my opinion it's somewhat easier to weld.
Hello vagabond, I believe that they are referring to FCAW gas/shielded as opposed to the self/shielded version. My recollections of the use of metalcore wires in their original offerings was mainly for use on robotic applications and also for use on tube steel applications where they didn't want to do a bunch of cleaning prep work of the anti-rust inhibitors. I believe the metalcore wires have a higher deposition rate than the solid core wires and still offer the lack of slag removal. These are just some of the items that I seem to recall hearing about the metalcore. Best regards, Allan
Well, there is the obvious difference which is Metal core doesn't have a heavy slag - just silicon islands. Gas shielded flux core does produce slag but it is usually easy to remove. One advantage of gas-shielded flux core is that you can get all-position wires where with the metal core, you are limited to flat and horizontal. There are plenty of all position gas shielded flux cored wires that will run on co2 or 75/25 but you won't generally find metal core that will run on co2 because metal core is generally run in a spray type transfer so you will need 75/25 or an Ar/O2 mixture like 95/5 or 98/2
So, I spent a lot of years doing structural fab and repair with flux core wire and 75/25 gas. It works great, is very forgiving and easy to use, once you get used to it.
Then I moved to a structural fab shop that used solid wire GMAW, flat position, spray arc with 90/10 gas. It worked fine, once you got used to it, but you were stuck in the flat position and really had to watch for penetration and spatter issues.
Then I did some comparative research and switched to metal core (after the prices came down to be comparative to the other wires).
I, and all of my shop hands have been elated since we switched. The metal core is so easy to work with, it flows like butter, wets on the toes perfectly, leaves almost no residual cleanup, and has excellent penetration properties. Once you figure in all of the costs of the process, it's cheaper as well.
I'm going to try to attach a excel spreadsheet that shows my comparative testing results. If it won't attach, just send me an email and I'll send it to you that way, if you want it.
Tim
I2R heating is increased in metal core over solid wire, because its conductable cross section is reduced, though not to the point of flux cored wires. As such FCAW wires have greater deposition rates over both, metal core over solid. With FCAW you gotta clean slag, with metal core not. Metal core has no position capability unless pulsed like solids
Arc density is also increased with metal core over solid so you get greater penetration, though not as much as with FC.
If all you are doing is flat and horizontal structural stuff, especially with greater thicknessses that actually allow you to take advantage of the greater deposition rates, metal core could be advantageous.
js55,
We changed to metal core about a year ago. We had been using FCAW-G. And while at similar amps/volt, the FCAW will deposit more. But with the metal core you can run at higher amp/volt. As an example an E71T-1 .045" is recommended to run at 26v&250a with a deposition of 9 lb. Metal core E70C-6 .045" can run at 32v & 300a with a deposition of 13lb. So wouldn't it depend on how you look at deposition? Or am I looking at this incorrectly?
hogan,
No, you're seeing it correct. Amps to amps as you say the FC will deposit more. The only question I would have is that I've run 045 T-1 a lot more than that recommendation.
Not really sure what the recommendation is based upon. It certainly is conservative. The max would be more related to the maximum current carrying capacity of the conductive cross section. Any mechanical based maximums would be an engineering decision.
Realistically, I think the best approach is to contact the variouus manufacturers or at least downlowd their data. Then try some for yourself.
Comparisons will always be "apples to oranges". We recently ran some "shop" test on FCAW, GMAW, and metal core. Guess what? They all had smoke, just in varying degrees. They could all be run in all positions, just some were easier than others and there were limitations that made some impractical.
Claims were made that GMAW had higher depositions rates than FCAW, or vice versa - but not when parameters were in the same general ranges.
Metal core was supposedly cheaper, but that proved untrue after we had all the quotes in.
What we decided was that we could use a metal core for flat welding but will likely always need at least some FCAW for the kinds of work we do - lots of oddball fabrication with a lot of out of position welding. (We still haven't rolled out metal core as yet).
One very surprising "discovery" was Hyundai wires. They ran very clean and low smoke with 100% CO2. Price was outstanding. The trouble was that we need USA materials for the majority of our projects.
Chet
That's very interesting about the Hyundai wire. We had terrible trouble getting Hyundai solid wire to short circuit with C02.. especially with inverter power supplies, but even the old transformers struggled with it. We also had an unusual rate of failures in the roots of guided bends with the Hyundai wire that simply disappeared when we changed to L56
The Manganise to Silicon ratio for short circuiting is best @ 2 to 1, although there is a broad definition in A5 as far as constituants. When we looked at the certs for the various solid wires we found quite a range as far as that Mang/Silicon ratio went, and it really did make a noticable difference with how the each wire performed.
This isn't even the first time I've whined about solid wire here on the forum :)
http://aws.org/cgi-bin/mwf/topic_show.pl?pid=96152;hl=hyundai
Actually, I hurried in wrapping up my post yesterday. I didn't meant to include the solid wires in my comment aboutHyundai , I meant only their FCAW wires.
We tried 75/25, 85/15, and 98/2 (O2) gases with GMAW- I didn't see any significant advantage over other brands. In fact we liked ESAB and Lincoln better than the Hyundai in that category. We did not run any of the GMAW wires with 100% CO2.
Sorry about the confusion.
Our shop uses both wires. We use McKay 71-v fluxcore for multipass welds and Corex metal cor-6 for single pass welds. The reason for this is because the Corex is not recommended for multipass welds.
Hi folks. We have used metal core for almost 20 years. Robotics, automatic equipment, semi-automatic. Our
production welding is flat and horizontal positions. But we have had also qualified many vertical and overhead welds, both fillet and groove to aws D1.1 for repairs and special projects. We weld carbon and HSLA steels.
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