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Up Topic Welding Industry / General Welding Discussion / Need Help 6g tig test
- - By chrisodom980 (*) Date 12-29-2007 00:13
I m tring to pass a 6g tig test. i have to tig the root and hotpass and stick out. i m putting a 3/32 gap and when i tack it up it does fine but when i weld it in postion it dosent have enough penatration any info would be helpful. I also have to do the same thing with 2 inch carbon with 309 wire.
Parent - - By ZCat (***) Date 12-29-2007 01:34
Use a bigger gap...5/32
Parent - - By chrisodom980 (*) Date 12-29-2007 01:44
if i use that big of gap do i need to use a bigger wire ?
Parent - - By Milton Gravitt (***) Date 12-29-2007 02:28
How thick is your landing maybe you need to cut back on it or make it smaller. I always tried to make my gap just wide enough where my rod wouldn't fall through.
Parent - - By cmays (***) Date 12-29-2007 03:22
Try what Milton said but run a knife edge (no landing). If youre gonna gap and land it I run a 3/16 gap and 1/8 land and feed from the inside of the pipe.
Parent - - By saipen7000 Date 12-29-2007 11:07
Hello to all of you gentlemen... I been visiting this great AWS forum  for a while and I like it, This is the first time I have the privilege to post  or reply... well, I just want to suggest to use a gap  of no less than 5/32  or 3/16 ,   whit feader edge( no landing) and  3/32 wire if you are welding pipe 4" I D or less end specialy if it is thin sch. Usin a 3/32 wire will allow you to use less heat  to melt it ,allowing you to have better control over the weld puddle and feed your wire from the inside like C MAYS said ...thank you. and have you all a happy ,healty and very productive new year, and your loved ones.   oh... dont forget to purge your 309.
Parent - - By chrisodom980 (*) Date 12-29-2007 14:08
the pipe is 2" sch 80 carbon its all going to be x ray.
Parent - By saipen7000 Date 12-29-2007 14:49
try  5/32 gap and use 3/32 wire, belive me it wont fail, I been welding tig for over 20 yr , thats what i do mostly ,specialy on boiler  tubes.
5/32" is enough gap for 3/32 wire , as i said you ar putting less heat on the pipe lowering the risk of it to get thigt by the time you get to the top side, also you are going to have less filler to put in, and this is an adventage  when you get to the cap, the narrow the cap area looks much better  on a small pipe. you can put narrow beads 2 or 3 with 3/32 rods,  dont wave it ,try to  make your rod to last all the way from bottom to top if you can. a cap with no tie ins looks very good.
Parent - - By ZCat (***) Date 12-29-2007 15:15 Edited 12-29-2007 15:17
I always like to be able to wiggle the wire in the gap, that way I can feed from the inside on the bottom. I don't use a land with TIG, but a lot of guys do. Keep the wire at the front of the puddle when feeding from the inside, that will cut down on the cold wire.
Parent - - By JescoPressure (**) Date 12-29-2007 15:24
just like ZCat said i set my gap just big enough  to freely fit a 1/8 wire into the gap ,i take the edge off of the bevel but no real land and feed the rod slightly to the backside of the pipe with slight oscillation from side to side to guarantee fusion along the joint and try to keep a steady travel .also a trick i learned was to tail out of your puddle and leave the rod in (freezing it in the puddle) while stopping to reposition or cut a bridge tack you will find that you can hardly see the start and stop when you do this
Parent - - By TRC (***) Date 12-29-2007 16:54
WOW, so many different replies and they all work! Personally I use the 3/32 wire and just less then a 3/32 gap, feathered edge and only enough oscillation to melt the wire. A full time trainer taught me about 10,000 days ago to take a feathered edge, 3/32 gap and 1/8 wire. Walk the cup (oscillate) just wide enough to move foward and just melt the wire. This will give the reinforcement on the insde that is needed as well as keeping the additional filler to a minium. Slow travel speed, excessive amps and wide oscillation on the root causes a low, wide bead. My techniques are only for small diameter and thin wall pipe. Ted
Parent - - By medicinehawk01 (**) Date 12-29-2007 20:46 Edited 01-21-2008 08:49
I use a 1/8" gap with 1/8" wire, knife edge. IF you use a little more heat than you are used to (5-10 amps more) and minimize the ocillation of the torch, you'll get a perfect root every time. The key is to keep the arc on the rod at the point it meets the gap. IF you move the arc around alot, you'll have suck-back or a poorly laid penetrating root.
Parent - By Aspirate (**) Date 01-21-2008 04:33
trying to preventing excessive dilution
its my problem in this test. I end up putting in the root the same way I do with 70S.  On sch40, I use a #5-6cup w/ gaslens and wiggle it in fast but still swirling.  I'm oscillating arc a little past the edges but not up the bevel.  Its the only way I can get the 309 to wet.  If I try to minimize oscillation (keep tungsten in center) it won't wet like im used to seeing, but is that what I should do to the 309?  I forget how the top color of the bead looked like.. probably shiny grey/purple/blue maybe.. anyways, if anyone knows more on this, could I tell if has too much carbon in it (hence excessive dilution) by the top color of the root?  
Parent - - By Jim Hughes (***) Date 12-29-2007 21:26
Chrisodom980

I use a 5/32" gap no land, with 1/8" wire. On this 2" test you will be moving fast. See if you can get away with three tacks. On the 309 test I would use 1/8" gap no land 1/8" wire and stay on top of the wire. Don't ossilate at all. If you can, free hand/finger the root and then on the remaining passes walk the cup. This is very important. Don't tell the person giving you the test that your first test qualifies you for stainless. Tester dudes tend to get upset if you know more than they do. :) Just kidding.

Jim
Parent - By chrisodom980 (*) Date 12-29-2007 23:03
thanks for the help i will give it all a try and see what works best for me, thanks to all.
Up Topic Welding Industry / General Welding Discussion / Need Help 6g tig test

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