This is a common test for certifing welders in stainless, it save $ on SS pipe coupons. You do have to purge. Why not weld it up with 7018 the pipe is A36 and the ID gets overlay. This process is a lot easier with more control and less chance of inclusions. If your doing it on rollers its 1G so...
A typical weld prep would be 30 degree per side 60 degree overall, with a open root of .062 to .125. Remember this will pull with out bridging. The root is up to the comfort of your welder. Remember to use a purge gas for back of root
if using GTAW process.
