GTAW Pipe

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OK, so I am going to try and gather the necessary material to do some practice. Last time I took a pipe test on GTAW I failed because the root pass did not have enough penetration. It was due to a lack of inexperience since I was only 19 when I took the test. I actually though it was 6010 root and hot pass with 7018 fill and cap. But boy was I wrong. It was heli-arc root and hot pass. SOoooo if im going to try to brush up a little at the shop im going to have to gather what I need. I have put my hands on a piece of 4 or 6" sch. 40 and 80 pipe to make coupons out of. We don't have a pipe beveling machine so I will hand cut and bevel each coupon. Next I found a tig torch set up brand new still in the box with 2% thoriated tungsten. The only thing I have not found is a bottle of Argon. Now since this pipe I am welding will be mild steel shouldn't I go 100% Argon? I have no foot pedal or high frequency set up. I will have to take one of the miller power sources and switch polarity. I will check if it has a TIG selection. Now on the regulator. Im pretty sure its a certain type am I right? I am a definite newbie when it comes to setting up the TIG system. Once its set though I can run it lol. Wish I was in a shop atmosphere that the process was already being used. Give me some pointers guys and what exactly I will need for this set up. I plan on buying my own machine soon. So the possibility I might go grab a regulator and couple extras myself to get the ball rolling. Might try to talk the owners into some piping jobs with 6010/7018 to start out with then if it all goes smooth throw in a little tig welding on pipe.Last edited by AndrewDavenport89; 04-01-2015 at 12:37 PM.
Reply:1. Yes 100% argon2. Feed the wire, don't drag it. 5/32 gap with 1/8th wire, ER70S2. This will give a convex bead about 1/16 high, not too little not to high.3. No high freq or foot pedals just dry rig on DCEN. 4. Try starting at 70-80 amps feeding the wire from just above the ID of the pipe inside the pipe.5. Sometimes turning the gas up all the way pushes the molten metal up to give a convex bead.6. The only thing you have to worry about with the wire feeding method is overpenetration. Pay attention to speed and amps.
Reply:Roger that! will do!now when you say feeding the wire from just above the ID of the pipe inside the pipe.....So your talking about feeding the wire from the inside. I fed from the outside when I did it. What happens when you get almost all the way around it....you cant feed from the inside the whole time right? I have seen consumable insert rings that you set in the root and fuse it in as the root then keep burning hot all the way to the cap.Maybe some pictures will help me visualize feeding from the inside? Originally Posted by Thegreatweldini1. Yes 100% argon2. Feed the wire, don't drag it. 5/32 gap with 1/8th wire, ER70S2. This will give a convex bead about 1/16 high, not too little not to high.3. No high freq or foot pedals just dry rig on DCEN. 4. Try starting at 70-80 amps feeding the wire from just above the ID of the pipe inside the pipe.5. Sometimes turning the gas up all the way pushes the molten metal up to give a convex bead.6. The only thing you have to worry about with the wire feeding method is overpenetration. Pay attention to speed and amps.
Reply:You're feeding intensity lessens as you progress up the sides and top. It is on the bottom that is the risk of suckback or IP because of gravity. So when you close the stringer at the top there is not really much feeding that has to be done, because again, gravity is pushing things down.Consumable rings? Is that the test or open root?I can't find any pics but here is another discussion.http://www.millerwelds.com/resources...n-Carbon-Steel
Reply:No on the consumable ring inserts I have not used them myself, but have seen them being used in my old shop before. Some old guy was in the back corner welding on pipe and he was putting these perfect sized rings he inserted into the root gap and when he got it all fit how he wanted he tacked it on 4 sides and took the tig rig and started going at it on the roll out. He finished and I checked out the root pass and it looked really really nice. Its almost like he made an autogenous weld right? but the ring is also a filler wire so maybe not lol.  Test ive taken was a 6GR 6" Sch.120 open root, 4 tacks 1/2" long throw it on the 45 degree and put a restriction ring on it. Now I have taken another stupid 6GR where you have a 6" sch80 and a 6" sch.120. The sch.80 piece was a square cut and the sch.120 was a 30 something degree bevel. tack it on 4 sides and put it on 45. The whole trick to this test is to see that you can push your 6010 rod all the way to the tip of the bevel and burn in. This proves you can do complete joint penetration on a SADDLE weld. (Large OD piping is saddled into other piping to make a cross beam). It is a structural test. Offshore lower structures are built all out of pipe. MCDERMOTT does some badass saddles on rigs and bases for platforms I hear.