GTAW of 321-321 stainless steel with 347 wire procedure/technique help

[aussiepipewelder]

Hey not sure if this is the right place, im a australian pipe welder but im seeking help on how to weld this grade of stainless steel,

Material- 4" schedule 10 seemless 321 SS to 321 SS

Filler wire- 347, 2.4 dia (cigweld brand)

GTAW- 2.4 thoriated tungsten 100% pure argon

Purge- 100% pure argon 10-25lt

Gap size- 3.2mm

Prep- Knife point

all welds need to be 100% and pass 100% x-ray

The problem that i am facing is control of the weld, huge and ugly root, not even and all over the place. even to cap it off its hard to control and make nice and neat.
i have never welded this grade of stainless with this type of filler rod before and neither has any of my co-workers and i cant get any help from managment because they havn't
touched the stuff either. i have search the net for hours unable to find any answers any help on the procedure or techique would be greatly appreciated.

Also most of the welds are in restricted locations requiring the aid of a mirror or other techniques to complete the weld.

Thanks

 

[DekDee]

Aussiepipewelder,
3.2 mm is much too wide a root gap for Sch 10 (3 mm thick) if you have a "knife edge prep".
If you are sticking with a knife edge close the gap up to 0 mm.
If the WPS does not allow this reduction in root gap then give yourself a small root face (landing).
10 - 15 lpm for purge - 25 lpm is much too high.
Good luck,
Cheers,
DD