Welding Tips and Tricks

I start Tue on a job welding what I assume to be cryogenic piping. I'm just a little out of practice on Al pipe, and can't afford to screw the pooch (long drive, motel, etc. with not much $ left from my last job). I'll be welding sch. 10 pipe, 3" through 14", both socket welds and butts with backing rings. For cryogenic piping, I suspect the alloy will be 3003.

I've never TIGged Al with a backing ring, and this is 100% x-ray. It is in a shop, so I shouldn't have any difficult positions.

The machine is a Miller 350LX (I've use the 350 DX, so no real transition there other than maybe pulse features).

How would you approach this weld?

Steve

Answer to your question is really moot unless you know what the WPS sheet calls for. I would assume that a job requiring X=ray NDT will require and provide one. Lets start there, Lots of ways to skin a cat.

trackmaster, I understand your reply completely.

However, no one from the shop forman to the cheif engineer seems to have a WPS for these welds. The assumption is that with 100% radiographic examination, the procedure didn't need to be separately qualified.

I was wrong about the material I expected; It's all 6061 T-6.

We got the wrong machines, too. We were expecting Miller SW 350 LX, and got some well worn Lincolns. In my opinion, the Miller is a much better machine for Aluminum.

On the plus side, the customer supplies the gas, and it's all 75/25 Ar/He. Also the idiot-savant I work with is the best welder I've ever seen. Think "Tommy". He's pretty helpless on his own, but he has years of nuke experience, excellent references, and the inability to stop talking until he falls asleep.

I'm a lot more comfortable with this job than when I made my original post. I did, however, suggest that I should be paid for "Adult Day Care". The boss said he'd work on it.



Steve

Hey instead of payin for day care just fly me out there and pay me 20 an hour cash :p