Root Options

By PipeIt

Date 01-15-2008 16:30

I might add no gap on the fusion approach.

By Kix

Date 01-15-2008 16:56

You'll suck it back in the out of position portions of the carbon pipe more then likely. Consistency will be way down. Best to use filler unless you're rolling out the pipe joint then i could see melting through a bit to give you a flush or above flush fused root. Knife-edge and filler is the only way to go man for a sweet tig root!!! That's just my opinion now, I know others that do it different. There are all kinds of ways to do it. I've seen guys weld the root in by feeding the filler in through the top of the pipe root opening and slick her in there.

By weldgault (**)

Date 01-15-2008 23:01

What position are you welding in, that could determine what you can do. John

By PipeIt

Date 01-15-2008 23:28

60% roll 30% 1/4 and 10% position.

By Shane Feder (****)

Date 01-17-2008 16:22

PipeIt,
Why are you doing two runs GTAW on Sch 40, what is in the WPS ?
A normal GTAW/ SMAW butt on Sch 40 will be root run GTAW, remainder SMAW unless it is small bore and you are doing the whole thing GTAW.
Feathered edge or 1-2 mm root face is all about welder preference. The pipe fitters set the butts up with a set up that the welder prefers.
As long as you stay within the parameters of the WPS there is quite a bit of flexibility in the set up for root preparation,
Hope that helps
Regards,
Shane

By PipeIt

Date 01-17-2008 20:01

Why are you doing two runs GTAW on Sch 40, what is in the WPS ?

Shane, we had some issues with melt throughs so we are doing two pass on the bigger bore stuff 8" and 10" tig welders are keeping up just fine. I questioned the practice but figured, oh well. We are following close to the WPS 1-32-1 and your right the parameters are giving us some variables. I am getting a real education on procedures and the lack there of.

Thanks

By Kix

Date 01-17-2008 21:32

I like to put a root in GTAW one pass and then i'll run a real quick stringer right over top of the tig root with a bit of manipulation concentrating my arc on the bevel walls beacause she tie in real easy on the thin center of the tig root. Haven't burnt through yet (knockin on some wood). ;-) Depending on the size of the shed 40 pipe sometimes i'm ready to cap right after that. Sometimes the procedure makes you do 2 tig passes just for the consistency of not everyone can stick over one pass of tig. And they wonder why some guys are faster then others. lol

By js55

Date 01-18-2008 14:36

A couple of things. Kix is right if you closed butt fusion anything but the top you'll have great deal of trouble with concavity. You can however use that for your rollout stuff though it still requires some skill to get the roots right. We did that regularly with machine GTAW, but not manually.
Also, with carbon steel, if you aren't already, run your GTAW over the top in what is essentially a downhill progression. Depending on skill you can drop down to as much as 35 to 45 degrees and really skate along, while running your amps to as much as 200 (or a little more with some pracitce) with 1/8" tungsten and 1/8" wire. With SMAW you will most likely need to run a hot pass, because this technique will generally leave your root a little thinner but it can still be really fast. but with skill and concentrating your heat onthe dside walls some of your guys may get away without the GTAW hot pass.