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Hi. I took a job welding carbon steel pipe in a fabshop. I am a field welder so alot of this is new to me. I haven't welded too much pipe with wire. The process is a hardwire root and then flux out. They are using. 045 wire for the flux, I believe a 70 series. Any tips would be appreciated. IE.... voltages, wire speed, how much fill before cap. Also should I grind after the root.I don't really have wagon tracks but I can see a thin line if silica on the ties after brushing the root pass. I've seen a few guys trap slag on their hot pass so I am concerned about that. Thank you
Reply:First off, you should have a WPS or multiple WPSs to follow, so that should be your deciding factor on your voltage/wirespeed. I was taught to always grind the root before the hot pass, though I've not done it and it will still pass xray if your edges are burned in good and flat. ALWAYS grind the humps of the starts/stops. If you are running carbon steel: I assume .035" hardwire for the root: I will run anywhere from 17-19 volts and 170-220 on the wire speed if you have a digital read out. I sort of "walk the cup" with the nozzle if you can get a small "pipe" nozzle that will fit deep in the bevel. I try to always have bridge tacks so its easier to cut them out and have a clean root. I weld opposite quarters, then remove the tacks, and feather all the starts stops. Reach inside with a old saw blade or similar to remove any burs. I always teach guys to "start low and end high. What I mean by that is when tying in to your original quarters, start with your pipe a little lower than you like to run it. I normally weld my root in the 930-1030 o'clock range. On a tie in, I will start at around 9o'clock. When i'm about to tie in to the end of a quarter, as soon as I get to the existing weld that has been feathered down, I will raise the pipe up to around the 1030-1130 o'clock range. The reason for this is to keep the tie ins smooth and not knotted/humpy. It will allow the weld to be real smooth and look like a "wedding band". The root is super easy, and you will love how it looks. The fluxcore, not as nice as stainless dual shield fluxcore, but not bad. I run about 28-30 on my varying passes, about 275-320 on the wire speed. Stay up on the pipe, if you get too low when rolling it out you can trap slag by having it roll under the puddle. Always stop and grind a ramp on your starts and stops, then finish your weld by starting and stopping on the ramps you just ground, so you are welding on clean metal. DO NOT WELD OVER YOUR SLAG. You will want your fill maybe 1/16" under flush before capping, and not too concave, just a nice flat weld almost flush. I don't like to weave with fluxcore, just a nice smooth bead. I always roll my pipe toward me, not away. Some shops want you to roll it "uphill" which would roll the pipe away from you, but if you can stay on top of it roll it away from you, it will weld much nicer. Try to stay between 11 and 1130 o'clock on the pipe. If you get too high on the pipe you will have a "hump" / "Mohawk" on your weld. If you get too low it will be concave. Obviously, the larger the pipe the more adjustment you have. Hope this helps, let me know if you have any other questions.Lincoln Idealarc Tig 300/300, Lincoln ranger 8, Lincoln LN-25, Miller Sidekick (keeps rockin!), Oxy/Acy torch, Miller XMT-304 with a Miller 60 series wire feeder and high freq. box, Profax positioner 8" chuck, Aaronson 3500# positioner 15" chuck
Reply:Thank you ,very helpful. I've been told that rolling the pipe towards you will burn in the toes better and you have less of a chance of trapping slag. However I am more comfortable rolling away. Any thoughts on how to not trap slag while rolling away.
Reply:What you were told is correct, however I feel it leaves a more appealing weld if you roll away. I make sure my toes of the root are real smooth, no edges showing, always ground smooth. I make sure when on my hot pass, and all other passes, I am not too far down, as I mentioned earlier. You will be able to tell if the slag is rolling under the weld, just as if you were running smaw. It welds similar to a jet rod, like 7024. Get too far downhill and your done for. If you are able to weld on the top of what you are welding, and the shop allows it, I would roll away from me. Hope that helps, if not ask away.Lincoln Idealarc Tig 300/300, Lincoln ranger 8, Lincoln LN-25, Miller Sidekick (keeps rockin!), Oxy/Acy torch, Miller XMT-304 with a Miller 60 series wire feeder and high freq. box, Profax positioner 8" chuck, Aaronson 3500# positioner 15" chuck
Reply:I have spent the last 3 years welding pipe with fluxcore on a positioner. We always rolled the pipe away from us when using flux core. Was taught to go hot and fast and not try to put too much metal down as the bigger the pass the more likely to have problems with trapped slag and possible lack of fusion. Little runs and stack them in nearly and keep the final fill 1-2 mm under I found gave better visual for the caps. You can grind the runs between every run to provide yourself a trough to follow which helps keeps runs very neat and uniform. We used to have to use between 28-30 v but did use 26-32v due to small bore and xxs pipe sch and anywhere between 35-60 wire speed. Haven't done solid wire root we tig rooted and hot passed our butts. If your using an automatic positioner use a stand to support the torch so you only have your wrist to control the torch. If you are and use a stand if you keep a chisel or saw blade in your other hand you can knock the slag off the start of your weld before you run over the stop start as it'll give you a much better finish. Treat it like a 7018 but runs twice as fast and you won't have no problems. Only other thing to say is that when we ran flux core we had a longer stick out of 20-25 mm and gas rate of 30/40 lpm gas flow.
Reply:I did experiment with rolling towards me on my hot pass today. I like it better because I can see the edges burn in. However, I didn't turn it down and blew through the root. I was running 28.0 v and 350 IPM. When running uphill what is a good setting. Also where should I run my puddle. I was about 2 O clock |
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发表于 2021-8-31 22:23:06