question on 6g certification test:
I need info on the set-up for the ua 41 certification using ss with tig. I will be practicing this so I can join the UA apprenticeship. Great website very useful. Thanks Justin
Justin, The UA 41 welding certification test is a 6g schedule 80 tubing test with a wall thickness of .436". It might be open butt, or with a consumable insert like a k ring, or with backing.
My guess is this 6g certification test will be open butt.
These joints are usually set up with a 1/8" (+ or- 1/16") gap and almost no land. I would set it up with tight 1/8 gap and use 1/8 rod for the root. You are going to need some practice because it aint that easy unless you have done a bunch of them. Some 6g certification test pointers I can think of are:
1. Fit up matters as much or more than anything, make sure you have a good fit with no mismatch and even gap.
2. Make sure you have a good purge and make sure you have a vent hole. More argon is not better, it will probable take 10 cfh or less to purge.
3. The root and second pass should be the same amperage. After that you can increase amperage a bit but don’t get carried away.
4. Don't get in a hurry; they will probably give a written procedure with interpass temperature limits. Meaning let it cool between passes, even if you are on a roll. Getting in a hurry won't help you.
5. Learn how to freehand using a "hotfinger" in case the inspector has pet peeve against "walking the cup".
6. Keep the red hot tip of the rod shielded in the argon and snip the wire if you forget or when you restart.
7. Electrode angle for the root should be pretty dead nuts straight in.
8. I would recommend a slight forward and back technique as opposed to the side to side you get when you walk the cup. I have seen both ways work and I have also seen cup walkers suck back the root pass.