Open root pushing out(GTAW)

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I noticed when welding open root using GTAW my root pushes out and turns gray and starts to flake on the bottom. Is it because I am welding too hot, and not letting it cool between passes. It's 3/8" thick and I add about 10-15 amps each pass after my hotpass. I usually run my root around 95-100 and my hotpass 105-110. Then I crank it up to 130 range for my fill pass. Then I run 2 overlapping fill passes at around 145, and stay at that range till my cap, with no cool time in between passes. Using 3/32 red and 3/32 filler. How do I stop it from pushing out?Last edited by smilexelectric; 09-09-2014 at 06:46 PM.Miller Maxstar 200 SDPiperliner #10 Gold
Reply:What do you mean by "Pushes out"? Suckback? Too much reinforcement inside?  Do you have pictures? I think when it turns gray and flakes its because its too hot for too long without shielding.Airco Ac/Dc 300 HeliwelderMillerMatic 200 (stolen)Miller Maxstar 150STLMiller AEAD200LE (welding and generating power) Hobart MIG
Reply:it is slightly convex root. then it literally pushes out the more I weld on it. The root flakes and turns a light gray color. I don't have pictures.Miller Maxstar 200 SDPiperliner #10 Gold
Reply:Pushes out of the pipe so its less convex or pushes into the pipe making it more convex? If it becomes more convex it could be the shrinkage squeezing it toward the center of the pipe. If it becomes less convex or even concave it could be suckback from too much heat, either too much amperage or welding too slow. With the flaking is sounds like too much heat, try moving faster.Airco Ac/Dc 300 HeliwelderMillerMatic 200 (stolen)Miller Maxstar 150STLMiller AEAD200LE (welding and generating power) Hobart MIG
Reply:Pushing into the pipe more. I will try moving faster.Miller Maxstar 200 SDPiperliner #10 Gold
Reply:Originally Posted by smilexelectricI noticed when welding open root using GTAW my root pushes out and turns gray and starts to flake on the bottom. Is it because I am welding too hot, and not letting it cool between passes. It's 3/8" thick and I add about 10-15 amps each pass after my hotpass. I usually run my root around 95-100 and my hotpass 105-110. Then I crank it up to 130 range for my fill pass. Then I run 2 overlapping fill passes at around 145, and stay at that range till my cap, with no cool time in between passes. Using 3/32 red and 3/32 filler. How do I stop it from pushing out?
Reply:Originally Posted by MinnesotaDaveWhy no cool time between passes?  This could be the root of your problem?Steel, stainless?Is this a pipe coupon or on a job?
Reply:I'll let the guys who know, answer if the guy is feeding you a line.But some things to maybe consider, a coupon is gonna heat up faster than an entire pipe.If your root is still hot and you weld over it, seems a good chance you'll re-melt it in some small fashion.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Originally Posted by MinnesotaDaveBut some things to maybe consider, a coupon is gonna heat up faster than an entire pipe.
Reply:I wouldnt think thats an issue with heat. I think it has to do with your stick-out or gas shielding.Ive had a lot of issues with that welding AL cast intakes, trying to dig in blind holes and fill them.Strike the arc, start to melt, then suddenly fluff up like pop foam and look grey? For me it was always an issue with shielding/stick out, when i wasnt paying attention to what I had my torch end set up for.
Reply:I doubt its my stick out or gas shielding. None of my welds indicate lack of shielding, and I am using a gas lens with about a 1/2" to 3/4" stick out in a V-groove on 15cfh.Miller Maxstar 200 SDPiperliner #10 Gold
Reply:I wouldn't worry about it. The metal contracts and that forces a tad more inside. The flaking is not an issue.
Reply:Welding tests are timed. You're expected to produce a quality weld under certain conditions. Speed being one of them. The root will push in. The coupon will be smoking hot. The root will flake from reheating but as long as there is no burn thru you're ok. sent while goofing off at workLong after the price is forgotten, the quality will remain.Both of my Poppy's 1954 Short Hoods -Third generation to weld with it and teaching a fourthSA 2## - Bought and sold more than I can remember or care to list, 8 in the shop right now
Reply:Well that's reassuring. I guess thats why they call for flush to slightly convex roots, due to reheating.Miller Maxstar 200 SDPiperliner #10 Gold
Reply:They want the flush root or slightly convex to be sure there is no unwelded pipe face  or voids I think they call them then as each added pass  cools it pushes the root pass into the pipe .If you look at the side section of your test piece ,before you grind off the renforcement you will see the whole area under the bevel is pushed in ever so slightly. If you bend  test with a void on the root it will open up or tear. Failure!Last edited by gxbxc; 09-11-2014 at 07:50 PM.