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Hi. I'm in a desparate situation somewhat. I've been trying to weld a 1/4" open butt in a 22 1/2 degree beveled v joint on 1"thick steel test coupon. There is a 1/4" backing strip. The root pass just won't come out clean. There is either a small pocket of slag in the center between the backing strip and the weld. Or there is a small pocket of slag at the edge of the bevel. It runs through most of the weld. The backing strip is not removed and the entire piece gets x rayed. These small slag pockets occupy space that should be filled with metal. I'm running 5/64" or .072" NR233 wire at 20V and 150 wire speed. Any tricks for getting that root done right. The rest of the weld seems clean as evidenced by dozens of slices taken out of practice coupons. I'm keeping 3/4" stick out and dragging the wire or pointing it into the puddle. It's a vertical up and overhead test. Its a lincoln 25 mig gun and a cc/cv miller box both 100%duty cycle and heavy industrial size. Electrode negative and good bolted down grounds. 4 separate set-ups with the exact same machines. Voltage on machine is same as voltage on digital multi meter. Any advise? Please don't advise if you haven't welded this type of wire. Thank you, PaidSlave
Reply:Originally Posted by PaidslaveThere is either a small pocket of slag in the center between the backing strip and the weld. Or there is a small pocket of slag at the edge of the bevel
Reply:If you don't watch the top of your puddle with NR-232 its very easy to roll a little kernel of slag into you weld puddle.Vantage 500's LN-25's, VI-400's, cobramatics, Miller migs, synch 350 LX, Powcon inverters, XMT's, 250 Ton Acurrpress 12' brake, 1/4" 10' Atlantic shear,Koikie plasma table W/ esab plasmas. marvel & hyd-mech saws, pirrana & metal muncher punches.
Reply:Grind clean all surfaces, tightly clamp all parts before tacking, preheat to between 150F and 350F before running the root. 20V DCEN is cold to me I would look to be getting 22-23 VDCEN at the feeder while holding a 1" stickout. .5V changes are big steps for this T8 type wire.
Reply:I like to burn each bevel down into the backing plate instead of making 1 root pass I make 2.. Try this it may help you :]
Reply:I think Justin T said it. Run two passes. But try to get away w/ making your gap a lil more than quarter inch. .072 is pretty big to be running two passes side by side. Are you running that big a dia wire for a reason. They make 233 in a .063 also. I did my verticle up w/ .068 232 in a single pass, and did my overhead w/ two seperate roots like justin suggested. 232 and 233 are both E71-t8 wires, and I'd think you could use either for your test, and be able to use either later on jobs. 232 has more penetration, so that would help you out on the slag entrappment between your backing plate and 1" plate your describing. Also 232 runs well uphill when angleing the feed of your wire downward about 15+ degrees. 233 does not. 233 runs good uphill aiming 90 degrees inward, but not downward. So if you could aim downward, I'd think that would help fighting the slag in the tight quarters that your in. Lincoln trys to push 233 as the new and better wire, but I don't agree in all cases. Its easier to run, and more foregiving. But 233 is softer wire, and doesnt feed as nice as 232.
Reply:I had some of the same problems a few years ago.This may help, its the same discussion with some good information.http://weldingweb.com/vbb/showthread.php?t=26734In that post is a link to herehttp://www.aws.org/cgi-bin/mwf/topic...4214;hl=nr-232There may be another link in there too that I printed off and still have.In the end, I think you need a little more heat. That stuff likes to run hot even out of position. My ranger 250 was barely big enough to run it. In the end, I won and my welds passed AWS visual, no X ray.Good luckDavidReal world weldin. When I grow up I want to be a tig weldor.
Reply:Oh also try pushing your root gap out to 5/16" that helps some. I don't know about making 2 passes with .072 i think you would be much more likely to trap slag with that combo.Vantage 500's LN-25's, VI-400's, cobramatics, Miller migs, synch 350 LX, Powcon inverters, XMT's, 250 Ton Acurrpress 12' brake, 1/4" 10' Atlantic shear,Koikie plasma table W/ esab plasmas. marvel & hyd-mech saws, pirrana & metal muncher punches.
Reply:hi,had the same problem,let me know if you still need help.mike
Reply:Turn the heat up, or do the root in two passes. You have a backing strip, no? V grove or single bevel with backing? Crank the arc control and keep it tight. Stay ahead of the puddle! Preheat anything above or equal too 1" if allowed.Last edited by mb_welder; 04-13-2012 at 09:40 PM. |
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发表于 2021-8-31 23:14:51