get a good purge. keyhole the root or feed from the inside, watch out for the root gap closing up. also keep it clean and let it cool down between passes. the tig part runs kinda trashy to me and sluggish if i remember right
scrappywelds is right BACKFEED the root and remeber it not stainless inconell is hard it stays were u put it but i have had some luck if u miss a wall turn up the heat wash over the root just dont suck it out if u do this look through the bevel while making a small repare or tape a clear lens on the top end of the pipe that way u can see everything
I sure wouldn't keyhole or back feed on a test if I wasn't already good at it. Those techniques take a great deal of skill.
And I'm guessin from the question that those skills have not been developed.
Widen the bevel and give your self a knife sharp feather edge. Make sure you point the tungsten right at the knife edge. Gap it very slightly smaller than the wire size, and crowd the puddle slightly by pushing on the wire.
Whatever Method you use for the root, be aware of the outside shape as well as the inside. Inconel doesn't do well with "washing over" or "Burning Out" discontinuities. The next pass if its TIG make sure the leading edge of the puddle is fusing with the underlying pass and base metal. If you have a rough contour on an underlying bead I suggest NOT walking over the wire or if you do pull it out and dip it when going over something with an uneven contour.
Use the file where needed. When you start stick welding I suggest weld placed stringers (some manipulation required even though its called a stringer). The nickel alloys have a tendancy to be convex in the vertical position if you are not careful. Be aware of bead placement and try to avoid any deep valleys created by the bead contour. If the rod wont touch on the tip, open it up some with a halfround file.
When you get to the layer before capping be aware of how much you want to fill. Flush top and bottom and slightly lower on the sides comes out nice for me as the beads are a little taller on the sides.
If they have marked the strap locations try to avoid starts and stops in that area.
Stagger your starts on the bottom to avoid too much buildup in an isolated location. File when needed.
Because the SMAW portion is often hard to control dont hesitate to add a little filler beaad to an area that is lower than the rest. Just be aware of the start location (straps) .
Dry Rods are preferred though I have been handed them right out of an open can from a gangbox on commonarc tests.
Inspect the rod for any cracked or irregular flux. It can be a pain coming up the side and the arc running wild.
Keep the coupon cool an convexity will probably be less of a problem on the sides. I have used damp rags when doing 2 or 3 commonarcs in a day .
Those are some of my opinions.
Have a nice day and Merry Christmas
Gerald Austin
Most of the things above would apply to any test.
if you will be doing any tig on it ....just be patient and remember you will have to drag that puddle along,,,always crap dancing around in the wet part. dont rush that and weld too hot....just drag it along where you need it and keep it warm and covered. Far as smaw goes...just go don't wait cause it don't look right...in other words keep your momentum steady and you will do better.
my $.02
TOmmy
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