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So I'm trying some self shielded FCAW wire for the first time... .035 Hobart E71T-11 in my new TWECO 211i, and the results are not what I expected... the slag is all soft and porous looking, ashy gray color, and doesn't even cover the entire weld. Also, while the weld underneath looks very nice, it is very dark. (Sorry no pics.) Please know I've run both dual-shield and 7018 professionally and just expected this slag to be similar, but maybe it's not? I'm running DCEN 18v@300ipm (per my chart) and it seems to be in the zone, running hot and smooth on 1/4" hot-rolled steel. I tried adjusting my parameters as well as travel speed and electrode distance with no real improvement.Am I doing something incorrectly or is this normal? Thanks,Jon
Reply:Without pics it's hard to say but generally self shielded wire has minimal slag build up, normally a quick swipe of the wire brush and it's nice and clean. Also there is much less flux to burn inside the wire vs a rod covered in flux.If the weld looks good when you brush the flux...... Your doing it right!Real welders know how to penetrate!(Equipment)Whatever can be used to beat my opponent into submission!
Reply:The slag may be looking ok, but you would only be running 80 or 100 amps on 1/4 steel ?
Reply:Looking at Hobarts sheet for their 21B which is E71T-11, you could be running a little low on voltage. At 160 ipm (120 amps) they're showing 20 volts. Usually, everything running sweet the weld bead is shiny."The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:I've run a good bit of FCAW-S. Generally if the slag is spotty, you're running way to hot, or way too much voltage. NR-211 will have spotty slag when run to hot for the size of wire. Here is some .045 NR-212.And 1/16 21-B. Attached ImagesDont pay any attention to meIm just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:Agree with everything said so far.Things I would check1) excessive voltage2) too large a beadHow large a weld and what type of weld are you making? If you make a single pass fillet too large by weaving you can see some windows in the slag coverage. Bead on flat plate will also show windows occasionally, even if nothing is wrong. Last thing, if the base metal is over heated, then you can see some windows in slag coverage. All that said, if you're seeing sound weld metal when you clean off the slag, you're OK. The windows in slag coverage are a sign that you're on the upper edge of acceptable performance for one reason or another. (unless you're running bead on flat plate)Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:This was one a while back, maybe a couple of years.I can vividly remember running the little HH135 at its hottest setting, and wire speed constant, for just about every weld on the stupid panels. The panels were 14ga, and the connector tabs were 1/4. Using .030 Weldmark wire. (I loved this stuff, it's no longer available locally, and was said to be actually made by Esab)So.........as far as running too hot, and that interfering with slag coverage Lottsa slag here What's underneath the slag 14ga 1/4 to 14gaIMHO, when looking at your puddle, really look at it. You can run very hot, and not have to mess with settings when switching between metal thickness, and still have decent welds. It's a matter of travel speed, and maintaining a nice liquid puddle. Flux core is a fast freeze process, and if you don't drag it at the appropriate speed it will freeze too fast, and look like crap. You have to maintain the same puddle appearance as a stick weld. Hot and fluid. To do this with, let's say an NR-211 type wire, keep stickout short and keep it hot. Shorter stickout with this kind of wire is about the best.Ripples come with a steep gun angle, which is ok, it's just how you're dragging the weld. Usually steep angles work best when running too hot for the material, or you're welding fast and hot.If your material is sized close to what your settings are at you have the luxury of running slow enough to make a weld that approximates a nice mig weld. .035 at 17-18v, can't remember the wire speed.I don't do any larger dia. wire, or different types of wire, so I can't speak to the issues with those particular set of variables.FCAW is a semi-automated process, and that's all the credit I give it. I truly feel that the process still depends on human variables to a large degree. Apply the techniques you learned with SMAW, and FCAW isn't the killer that most folks tend to say it is."Any day above ground is a good day"http://www.farmersamm.com/
Reply:It's kinda odd, because each brand has it's own parameters and sometimes they aren't one for one across the board. Hobarts Fabshield 21B wants 20 volts at 120 amps, lincolns NR 211 wants 16.5 volts at the same 120 amps, Hobart actually has two E71T-11's. One is the Fabshield and the other is generic E71T-11 with no glitzy name. So-on. A guy should really get the spec sheet for several of the manufactures just a a quick reference when you can't get it dialed in. Pretty much the self shielded likes to run in a 'spray like' mode, CTWD sensitive, voltage sensitive (for the brand), with several sweet spots up and down the amp range. Each time you sort of have to feel out the wire speed to IPM relationship."The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:Here is some 30 + year old NR-211 I found in the top of my Dad's barn. The roll had some rust on it. Attached ImagesDont pay any attention to meIm just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:Thanks everyone. All great info and I really appreciate it. Sounds like I'm running too much voltage for this wire. That's what I had thought too, at first, but my puddle and finished beads were all looking good. I was pretty much running it like 7018 and the finished weld looks very similar, hot and finely rippled. For the record, it is Fabshield 21B. A-Dab-will-do, I was just making horizontal fillet stringers, varying my travel speed to result in welds 1/4 - 3/8" across their faces. Bluewelders, the charts I can find show me I'm around 130A+. How did you come up with 80-100amps? It's wild to me how much different the charts are with FCAW, between Hobart showing 160ipm@20v (then I'm WAY off!!!) and my machine showing 300ipm@18v (for 1/4") and then the Lincoln wire is different, too. Is it the wall thickness of the wire that could be way different, carrying more or less current and providing more or less filler? Wish I had a nice garage to play in but I've been working outside at my house and it's snowing at the moment. When I can, I'll try turning down the voltage, or up the wfs (a lot more than I was) and see what happens. I'm trying to run it hot, and turning the voltage below 18V on 1/4" just seems too low. Maybe I'm just used to GMAW where you can see the arc more clearly and hear it sizzlin'. Should I be tuning things for the same "sizzle" as with GMAW, or running it hotter and on the spray end of things (which I'm doing now)?Thanks again.
Reply:This is a finished weld. Did not take pics during the process. I thought it looked alright all said and done, but the slag was just terrible looking.
Reply:ESAB says:7.7.11 EXXT-11 - These electrodes are self-shielded and operate on direct current, electrode negative (-). They are general purpose electrodes for single and multiple pass welding in all-positions. The arc is relatively smooth and spray-like.http://www.esabna.com/euweb/awtc/lesson7_1.htm"The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:It seemed that was about where the Volt-Ampere Curve would be for something like a Millermatic.Been too long I may have gone a bit off kilter. |
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发表于 2021-8-31 22:12:38