Under the Table and Welding

admin

(note: the title of this post is a reference to the Dave Matthews Band album "Under the Table and Dreaming.")Found some pics of one of the last lab objectives I did in school before graduating (Aug. '07): 5G limited access.The parameters:Material: 6" Heavywall Pipe (5/8" wall)Joint type: V-grooveBevel Angle: 60 degree included angleRoot Land: 1/16"Root Opening: 5/32"Position: 5GSpecial: bottom of pipe can be no more than 4" above the groundRoot/hot pass:Process: GTAWFiller: ER70S-6 (1/8" diameter)Shielding: ArgonAmperage:Root: 110 AmpsHot pass: 130 AmpsProgression: upFill/Cap:Process: SMAWFiller: E7018 (3/32" diameter)Amperage: 80 AmpsTesting: 4 side bends per ASMEClick all pictures for a larger view.Here's the fit-up. The pipe is ground clean to at least 1" outside the joint, inside and out. Tacks are ground down to ensure that they tie in to the root bead properly:The requirement that the pipe be no more than 4" off the ground means that there is just barely enough room for the TIG torch, even when using a short back-cap:Here's me curled up under the work table putting in the bottom part of the root. Note that the filler is fed through the joint and into the puddle on the inside of the pipe:Here's me putting in the top of the root pass, now I'm kneeling under the table: (I just wished I had remembered to come out from under the table before trying to stand up.)Here's the root. I had to use a narrow gas cup and a long electrode stickout to reach far enough into the groove:Feeding the filler on the hot pass required some "creative" filler manipulation:Here's the hot pass:Now it was time to swap the work and electrode leads and switch the machine over to SMAW (Stick) mode to fill the rest of the joint with E7018. Naturally it's rather difficult to fit a 14" long electrode into a 4" gap, so we bend the electrode like so:Clamp it in the stinger (electrode holder):And weld:When doing the very bottom you can't see the puddle so you just have to guess what it's doing until you get far enough along in the joint to actually see. Also, the bottom of the pipe has lots of restarts since 4" of rod will only get you about an inch and a half of weld when you weave in a joint like this.(Continued in next post)Visit Tensaiteki.com
Reply:(Continued from previous post)Anyway, my camera batteries died right after that last picture so I didn't get any pictures of the fill passes.I managed to get new batteries in time to get a pic of the cap pass. It's not quite as good as I'd like but the "inspector" (read: instructor) signed off on it so it's good enough:Here's a pic taken after I cut out and bent the four specimens (see ->this<- thread for pictures of similar specimens being prepped and bent):And a closeup of the bend tests:If you look really close at the last picture (click on it for a larger view) at the top and bottom edges of the specimens, you can see how it looks like the weld got "sucked in" to the piece when it was bent. This is because the pipe is made of a higher strength steel than the weld metal.Generally, the higher strength a steel is, the higher the yield strength. The yield strength is how much load/stress/force/etc. a metal can take before it will plastically deform (bend, and stay bent when the load is removed). During the bend, the weld metal, with its lower yield strength, began to deform first and stretch. If you've ever stretched out a rubber band or piece of rubber you've seen how the more you stretch, the thinner the middle section gets, the same thing happens with steel (and other metals) except that steel won't spring back (as much).Both of the filler metals in this objective were of the 70 class (ER70S-6 and E7018). In this case the filler metals were under-matched to the base metal. In the real world, this is not always a bad thing, even though the weld is weaker than the base metal, it might still be plenty strong for the expected service of the weldment (plus, the filler is usually cheaper than the higher strength stuff.As a side note, at work we use 80 class electrodes (ER80S-D2 and E80C-D2) and out test plates are regular A36 steel (basically your average, not particularly strong, mild steel as is used in most structures, I-beams, angle iron, etc.). Here, the weld metal is (very) over-matched to the base metal. When we do bend tests the opposite happens. The weld is stronger than the base metal so it actually sticks out slightly from the base when bent.Visit Tensaiteki.com
Reply:Nice work.  I do a good bit of agricultural irrigation piping and we use 6" & 8" sch40, and alot of time the pipe running into the irrigation will only be 3"-4" off the pad its anchored to so I can sympathize with that procedure.I'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......
Reply:Outstanding work !!Anything worth doing is worth doing RIGHT
Reply:That looks too familiar!  We were doing something similar at work the other day, except we only had about an inch and a half clearance from the pipe to the wall.  It was about 2.5" pipe.  It was a bitch, even the best of the pipe welders had leaks.
Reply:nice! and i got the DMB reference before clicking the link
Reply:Awesome work for such limited access. Now you are qualified for all the hard ones, maybe a little more moolah! Nice job again.
Reply:Great work, thanks for the pics and tutorial.
Reply:Nice documentation!- ASODBeauty in the Bead!
Reply:that looks really hard! good job. but why under a table?http://datingsidorsingel.com/
Reply:wow, awesome work! "Ask not for whom the bone bones, it bones for thee" - Bender
Reply:oops.......Last edited by Brainfarth; 09-11-2007 at 02:50 AM.Common sense in an uncommon degree is what the world calls wisdom.
Reply:I would copywright the image.Can I post that on my new wesbsite? Last edited by Brainfarth; 09-11-2007 at 02:51 AM.Common sense in an uncommon degree is what the world calls wisdom.
Reply:Very Nice!DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Tensaiteki  Very impressive!Thanks for the great photos.I bet it difficult to find welders that can do that weld (without a bunch of practice).  The only way I could it would be by machine.
Reply:Did you take a slice from the hard to reach bottom for the bend test?
Reply:nice job glad i dont have to do thatChuckASME Pressure Vessel welder
Reply:I have done the same thing..Well not the same.. But I'm sure we all have here at one time or another... But the stick welding laying on your side..Tigging chassis parts with no lift.. I feel your pain my friend...But you have real talent...I just love stick welding what you can't see.. Keep up the laying around.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:No mirror for the bottom? It does make it a lot easier, once you get used to the mirror.
Reply:Excellent welding Tensaiteki.  Can you educate a rookie:  Why did you switch from tig to stick for the filler passes?
Reply:Originally Posted by GLwelderExcellent welding Tensaiteki.  Can you educate a rookie:  Why did you switch from tig to stick for the filler passes?
Reply:Originally Posted by bluduk15Excellent post, learned alot because of your thoroughness.  I would like to know about the switch from TIG to stick too.  Is it just for learning purposes or does it have some structural/engineering reason?Again, great work.
Reply:Wow, an instructor that's trying to make it real. It's done under the table and on the floor to simulate the real world. Why, because you seldom ever get to weld anything in a comfortable position.The college at home is geared for oilfield welding and is taught by an old oilfield welder. Final exam is a hot tie in with all the safety people, the fire department, and such. Set everything up, turn on the gas, light it, and go to welding. When it's over it is x-rayed and then subjected to destructive testing. If the weld doesn't pass, neither do you.For you up and comers always start the root and hot pass on the bottom and finish on the top when doing that. Three guesses why, heheh.The difference between art and craft is the quality of the workmanship. I am an artist.
Reply:Originally Posted by Tensaiteki(note: the title of this post is a reference to the Dave Matthews Band album "Under the Table and Dreaming.") ...
Reply:this kind of posts own!great job man!My Babies: HF Drill pressHF Pipe Bender3   4.5" Black and Decker angle grindersLincoln Electric PROMIG 175that´s it!BEAUTIFUL post, very informative too!  Your definition of "yield strength" cleared up some stuff for me lol.  I'm a huge fan of simple explanations.  Nice work too man, good effort!Have a Jeep Cherokee?  Click Here!