high pressure pipe help!

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so this week i plan on messing around with some 2in 1/4 wall pipe for some upcoming test the boss wants me to take.one will be mild steel and the other will be stainless. as far as the mild steel one goes i belive it's a 37.5 degree bevel not sure on the landing.so i figured a 6010 for the root and a 7018 fo fill and the cap. now i have a good 2 months to practice for this so i'm looking for some pointers.the initial test is in the 6g position is it better to use a 3/32 rod or a 1/8 rod.any help would be great!
Reply:On pipe that small you would be better off putting a TIG root and hot pass in it and fill it with 7018.  thats the basic stick test for the UA.  On a 2" stick all the way, we use XXH pipe.  We do all tests on a 45deg.  Not sure if that's 6G or not,  I've forgotten all the G's.  Anyway, if you have to stick it, you'll probably want to put a nickle thick landing on both pieces and but them up, or maybe just a hair of a gap and key hole it with the 6010 for the root.  then grind it, slick it up and fill/cap with 7018.  Anyway, happy rod burning.Oh yeah, probly use a 3/32 with pretty low heat, maybe 50-55amps
Reply:Seeing as how I deal with descale pipe in the steel mills at 3000psi and 24" and 20" also some 10" and 6" sch160 pipe.You said it had a wall thickness of 2.25" that would be larger than 20" which is 2" wall thickness. We run a tig root sometimes and a 6010 sometime. Weld out with 7018 1/8 or 5/32, the latter is what I use.Just make sure to pre heat and stress relieve the parts to be installed.If you have any questions ASK.The only stupid question is one NOT ASKED.Brett B & B Fabrication and Welding Inc.Spalding, MI.
Reply:I did my pwp #7 which is 2 and 6in sch.40 in the 6g position. You want your included angle to be 60-70*, root opening 3/32 and landing 3/32. As a rule whatever my root opening is, my landing is the same. Make sure you feather your tacks good for some nice tie-ins and use a 3/32 6010 for your root. Grind out any wagon tracks and lay in a hotter hot pass. Fill and cap with 7018, your choice 3/32 or 1/8. I prefer 3/32, able to control the puddle alot nicer. When welding the root, weld from 3 o'clock to 12 o'clock, then 9-12 o'clock, then go from 6 up to 3 and 6 - 9.
Reply:great info guys.... also i was told by a guy that has been doing pipe for years to not stop on my tack go past them. any truth in that?also for the root do you guys push the rod through the beveled edge or just drag it?
Reply:Make sure your 4 tacks have full penetration. Then feather both edges on all 4 tacks. If you are welding smaller dia. pipe then easier to start at 3 o'clock. Strike your arc ahead of your tack and keep a long arc until it stabilizes and move it back onto the tack and shorten it and allow it to burn through. I just drag my rod along the landing edge. I know some like to whip there whole root, but I prefer to drag. Also I like to look down my electrode like looking down the barrel of a rifle. That way I can see behind and in front of my rod, and can keep a eye on my keyhole. When you get up to the tack at 12, keep moving past the feather edge and stop in middle of tack. Make sure you have a complete tie in and proper penetration and such. If not then take a zip cutter and feather back. The guy who told you not to stop on the tack it right, you want to keep moving through that feathered edge, stopping in the middle. After root, get out a grinder and grind any wagon tracks you have and lay in your hot pass. When you start doing it post some pics inside and out.
Reply:You also want to avoid start and stops right at the top and bottom. For a bend test, the test pieces are generally cut from the 1:30, 4:30, 7:30, and 10:30 points, so be SURE to mark a) your top of cylinder and b) which is the uphill piece of pipe. The test samples need to include (under ASME) a total of 1 sq inch or more of material, and need to be bent two out and two in (one from top and one from bottom for each) OR all four side bends (again one from top and one from bottow uphill, one each downhill)Wider angle on the prep (90 degree included is the widest allowed in many standard procedures), the easier the access and less likely to trap slag, but more filler is needed, and more heat to put it in. Narrower angle will go faster, use less filler, use less heat, but you need to be a lot more careful with the cleaning at stops and starts and between passes. Your power wire brush and your grinder are your two best friends. When in doubt, grind it out.
Reply:I was a millwright in a big factory and we had lots of hydraulics. After about 10 years of line stress the lines started leaking almost 1 per day. I ground out the weld and gave it one hot pass with 7018 and back in service. You couldn't go more than 1 pass because there were bolt holes in these blocks to bolt everything back up. Mine are still holding fine after 7 years and 3,500 psi...BobBob WrightSalem, Ohio  Birthplace of the Silver & Deming Drillhttp://groups.yahoo.com/group/southbend10k/http://groups.yahoo.com/group/sawking/1999 Miller MM185 w/ Miller 185 Spoolmate spoolgun
Reply:Sorry for the slightly off-topic post, but how do you get an accurate 37.5* on a peice of pipe that big, a small dia. pipe could be put on a lathe I presume, but how do you do it to a 2ft+ pipe? How accurate does it have to be?
Reply:It doesn't have to be that accurate.  You do it long enough and learn what's acceptable and whats not.  At work we have torches and grinders set up to cut or grind the pipe while it's on rollers.  And to clarify, you're welding 2" pipe with 1/4" wall right?  That's sch 80 I believe.  Just make sure you slow down on the tacks to tie in well.
Reply:A few more things:If you know where the test pieces will be cut, try to kep the tack out of the area.As you run to the tacks, it is often handy to just remove them, rather than feather and consume them. Grind them out before you hit them, if you want. The weld you have already done approaching the tack will support things just fine.A pipe threading lathe makes a great holder for beveling.If you root with 6010, use 3/32, not 1/8. Better control as you learn. Run a hot pass immediately after cleaning the root. This shoould bring you about 1/2 way. A couple passes with your choice of '18 and Bob's your uncle.If this needs to meet a particular code and procedure, get the details before you start practicing. For example, the standard prequalified procedures for ASME (like ANSI/AWS B2.1-1-021-94 for TIG root/'18 cover) uphill progresion.   You have 15 degrees to either side of bottom that are 'overhead'. Outside that zone, uphill is it.If you don't have one, make a fixture for the 6G. You want to be able to adjust the height and position, have a hookup for the purge for the stainless, and have it hold the proper angle. A few hunks of pipe and a bolt will do it. Get an inspection mirror and flashlight for inspecting your root. You can't so poop from the end without them.Have someone with some skill watch you run the root from the opposite side through the gap. They will be able to see if you have full consumption of the edges as you go, and you will quickly recognise problems when they are pointed out immediately. Attached Images
Reply:pipe  teste her eon on  schedule 120 2 " pipe on the 45....coupons are  beveled  sharp..welder puts his own land on...make one  tack..then  mark where your  other tacks will be....keep them where you will make  your  cuts....mark  them  so you will cut  right through your  tacks.as  stated earlier try  and  grind your  tack  just enough so you will weld  through it  again when you get to itmost  guys  i know  do  the root  with  1/8 6010 and  then use close to the  same heat to fill with 3/32 7018some  tests  are  done with  tig root..depends on  what you are testing for
Reply:Where i work our 6" 6G test is with sch 80 pipe beveled to a point, 1/8" gap, 3 tacks and all uphill with 1/8" 7018. No noticeable burn thru on the ID, full penetration with no noticable gaps on the ID. Then the inspector looks at it when done and if it passes his visual it goes to Xray. One test, one perfect weld if it dosen't pass you are back on the street. Tough as heck and there was a dump truck load of test pipes before me...BobBob WrightSalem, Ohio  Birthplace of the Silver & Deming Drillhttp://groups.yahoo.com/group/southbend10k/http://groups.yahoo.com/group/sawking/1999 Miller MM185 w/ Miller 185 Spoolmate spoolgun
Reply:another method would be to use bridgeing tacks at 12 9 and 3 start about 5 30 weld past 6 to the 12 position each rod should be enough to reach a tack.when you remove a tack the gap should be untouched carry on your root.
Reply:Well, i see what the key hole is... guess i was to hot when i started my tacks the hole was twice the size of the rod...lolwould 2 plates of the same thickness prepped the same way be good for setting up my machine.well grinding to a point didn't work for me this time i will have a 3/32 gap with a 3/32 landing since i will be using a 3/32 rod. since were fresh out of 6010 how does a 7018 deal with the root, being as it is only a test piece?
Reply:The way we do it is as you described.  3/32 root, 3/32 land, 3/32 rod.  For the most part you can let the root "fill" by keeping the rod at the very base of the root, if not slightly inside the pipe, and if the keyhold opens up on you, transition to a slight "u" motion.  Changing my electrode angle to a push angle will open the keyhole up some if it gets too tight, changing it to a pull will help close it up.  Feather the tacks out rather than removing them.  This ensures that you have the same root opening and land you started with.Stagger your starts and stops.  On the bottom, start one inch to the left of 6:00, next time out, start one inch to the right, next time at 6:00, etc, and stagger around the pipe.  A lot of tests are a permissible 3/8 max porosity with stick, but if it's all clustered together, it's a reject.7018 is kind of a waste on the root.  You'd need to thin the land out some as it doesn't have the penetration that 6010 does, but you may end up with a mess on your hand and some trapped slag, as its not fast freeze like 6010.
Reply:if you are running a tig root on stainless or carbon no land is needed u can achieve a better root with less distortion with a feather edge.  just remeber to purge your stainless
Reply:Originally Posted by infamousjerif you are running a tig root on stainless or carbon no land is needed u can achieve a better root with less distortion with a feather edge.  just remeber to purge your stainless
Reply:i do the same just to get the bur out of the id from lathe