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I have a test at any point in time I want it for a very good company in a shop not to mention excellent pay. The only "problem" is that I need to practice. Why? 6G MIG/FC on 2" schedule 80CS. 75/25, mig root, flux the rest of the way. .032 or .035 wire in a 1/8" gap. Other test is tig on the same pipe, I am very comfortable with that. I told the gentlemen offering me the test that I would get back with him in a week to relay progress of my trigger welding. I am mainly asking for suggestions to help me learn quicker and so I do not screw up the bevel and spend 80% of my lab time prepping metal. My problem area with open root mig welding is nudging the wire a hair too far in front of the puddle and sticking it thru the gap. Best way to combat this? I understand the coupon will get extremely hot, I will wait a good while in between passes.-Land/root face suggestions?-Bead sequence suggestions?-I will mess with the settings on my own, but I would gladly accept a starting point in order to not goof the first bevel I weld. Again the wire is .032 or .035.Most of my concerns are on the root, but I am open to any suggestions on the flux core as well. I am thinking I will prep 3 or 4 coupons and practice the root first. Is there any sense in welding hot/fill/cap passes over a root that looks like tree bark?TIA
Reply:No specific suggestions, but a few general ones.I tell my students that I help that prep is 90% of the battle when they get to bevel but joints. Those that skimp on prep and have poor fit up almost always fail. Those that follow my instructions on getting the fit up right almost always have an easier time. It's not at all unusual for student to take a coupon I prep and get decent roots in. When I have them prep, they fail no matter how many times I tell them what to pay attention to. Make sure your root gap, land and bevel are consistent and sized properly. If you have to prep yourself for the test, take the time to get it right, not "close enough". It will go a long ways towards making your life easier.As far as keeping the wire on the leading edge of the puddle, I tell students to stay in tight and swing slightly back and forth from side to side watching the puddle. Not much more I can easily explain with text. What I see and you see could be completely different.For practice with open roots, you might want to start with flat plate vs pipe. It's easier to prep and if all you want to work on at 1st is keeping the wire on the edge of the puddle, it can help get you some simple practice in before you complicate things by constantly changing the gun angle going around pipe.For prep, it might pay you to have someone with a lathe prep a bunch of coupons for you if you are serious and have the money to spend. The "cheap" way is to do it all yourself by hand, and not a bad thing if you will have to prep your own stuff, but you will pay for this in time and possibly poor fit up.I'm not quite sure I understand your "tree bark" comment. Good luck..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:I'm ASSuming he means a root that looks like crap and is really rough.
Reply:For your solid wire root.1/16" to 3/32" land.About 3/32" root opening. The 1/8" root opening you mentioned is a little wide for me on such small diameter pipe. be prepared to weave side-to-side on the top to keep from burning through.4 tacks, 1/2" long, and well feathered, is the safe setup.Weld the root downhill. Not much advice for avoiding punching through and leaving whiskers. Time welding is the best way to fix the problem.For CV MIG with 0.035" and 75/25 gas; try 16-17 volts and 150 inches per minute. Probably on the hot side, so be ready to turn down from here.For the fluxcore, run a stringer hot pass uphill. Move quickly and weave to achieve a good flat bead and avoid burning through the root. Check the wire manufacturer's spec sheet for low heat settings; something like 24V and 225IPM wire feed speed(0.045" FCAW wire). Might make for a lot of spatter at those low settings, so keep a short stickout to minimize the buckshot. Let the coupon cool before you put the next bead in.FCAW fill pass you can weave and run 24-25V and 250IPM. Cap can be 2 stringers. Let the coupon cool before you try and cap out. Turn Voltage down closer to 24V and hold about 1/2" stickout if you have trouble with undercutting the toelines. Again, these are general suggestions. The FCAW wire may need more voltage or less depending on who makes it. Originally Posted by GoinesI have a test at any point in time I want it for a very good company in a shop not to mention excellent pay. The only "problem" is that I need to practice. Why? 6G MIG/FC on 2" schedule 80CS. 75/25, mig root, flux the rest of the way. .032 or .035 wire in a 1/8" gap. Other test is tig on the same pipe, I am very comfortable with that. I told the gentlemen offering me the test that I would get back with him in a week to relay progress of my trigger welding. I am mainly asking for suggestions to help me learn quicker and so I do not screw up the bevel and spend 80% of my lab time prepping metal. My problem area with open root mig welding is nudging the wire a hair too far in front of the puddle and sticking it thru the gap. Best way to combat this? I understand the coupon will get extremely hot, I will wait a good while in between passes.-Land/root face suggestions?-Bead sequence suggestions?-I will mess with the settings on my own, but I would gladly accept a starting point in order to not goof the first bevel I weld. Again the wire is .032 or .035.Most of my concerns are on the root, but I am open to any suggestions on the flux core as well. I am thinking I will prep 3 or 4 coupons and practice the root first. Is there any sense in welding hot/fill/cap passes over a root that looks like tree bark?TIA |
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发表于 2021-8-31 22:43:37