INTO the WORM HOLE

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I've been preparing to take another certification test (FCAW this time) but have run into something I can't figure out.I'm using the training centers Miller Mig welder (Diversion 180 I think) with Essab dual shield flux core .045 wire.The machine is set to 24.5 volts and am using 75%ar-25%c gas (28cfh on the flow meter).The test coupon is  1" thick plates with a 22.5 deg angle,1/4" gap backed by 3/8"  plate in the 3-G position.I've been running a bunch of test pieces and have been running into something that's best described as "worm wholes". I'll get periodic section of this but I can't figure out what's causing it.  This is NOT the type of porosity that takes the form of lava rock but rather long tubes buried in the weld. I've ground some of these for an entire inch before coming to the end of it. I'm thinking it's a stick out length issue but I'm not sure. I wish I could do it on command but there doesn't seem to be any rhyme or reason to when it will show up. I will add one more ODD thing that is going on but I don't know if it's related. At the end of my welds on occasion I've had molten metal ejected from the end of the weld like some-one squeezing a tube of toothpaste. It's the oddest thing and only 3/8 to 1/2" long but I thought it might be worth mentioning.I'd like to sort this out before taking the test.GizzmoSyncrowave 250 CK aircooled tig
Reply:Sounds like you have bad gas or possibly a leak somewhere. GarLincoln Electric, Power MIG 256Hypertherm Powermax 45 Miller Dynasty 280DXSmith O/A torchGenesis of a welding table
Reply:It happens, sometimes it's too much voltage. Or the wire has picked up some moisture. You may have to place the wire in an oven to dry it out. Attached ImagesDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:It's none of the above, this is more common with duel-shield wires, and high strength steel alloy's (like cro-moly), the problem can be partially taken care of with post flow gas (gas flowing over the weld after you finish welding, most high end machines have this), but as the wormhole is caused by the weld metal suddenly cooling and contracting  when you finish a pass, that won't completely solve the problem.try pre-heating the plate to around 450-500 degree's to slow the weld cooling, and when you finish a pass, come back on on yourself about 1/2 insh (as if you were finishing a pass with a stick weld), otherwise, try more wire (180 amp's at 24.5 volts sounds low to me, but then again every machine is different), I sometimes find if i extend the stickout to around 3/4 of an inch for the last 5/8th inch of weld, then push the wire back in as I finish the pass it sometimes help's.
Reply:Here is a good article from Lincoln about troubleshooting FCAW-G. ESAB also has a good article on worm tracks, but their site is down at the moment.http://www.lincolnelectric.com/en-us...ess-welds.aspx Attached ImagesDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:in all  I've read on the net they are referred to as "worm tracks" and show up on the surface and not IN the weld.the photo CEP posted is typical of the worm tracks I've read about but they don't look like what I've been seeing. I've also read the Ar 25%CO2 may be a contributing factor. ttoks- I'm welding on common steel plate (30,000 lb/sq in I think). The worm holes I've encountered can happen at any time during the weld and not just at the end, but I will look into the available settings if for no other reason than to know it's available.thxCEP - I'll check out that link as soon as it's up thanks.There is so much Bad info out there it's hard to know what to trust- that's why I come to you guys.Thx,GizzmoSyncrowave 250 CK aircooled tig
Reply:Are you hooked up electrode positive. Your settings seem kind of cold. I would go to 26-27 volts and 300- 350 wire speed.Miller xmt304,  Miller S22 p12, Miier Maxstar SD, Miller 252 w 30A, Miller super32p12, Lincoln Ranger 9, Thermal Arc 181I with spoolgun, Hypertherm 10000 ,Smith torches. Esab 161lts miniarc.
Reply:One thing with dual shield. You have to follow the manufacturer's recommendations. If they say 3/4” to 1” stick out, you better do it. If they say 45-CFH you better do it! This is the ESAB link, but it's still not working! http://www.esabna.com/us/en/news/new...orm-tracks.cfmDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:Something else to consider (you kinda already mentioned it), try welding with straight CO2.  That's always worked good for me with dual shield.  The last project I had was with 3/4" A36 steel, dual shield, and CO2.  Came out perfect.GarLincoln Electric, Power MIG 256Hypertherm Powermax 45 Miller Dynasty 280DXSmith O/A torchGenesis of a welding table