how to weld aluminium pipe 6g position????

[sani_ppg]

hai...

i want to ask you all...

why penetration is not complete...aspecialy from

overhead

to vertical position?

Type of aluminium is : aluminium pipe grade 4000 series schedule 10 ( thickness 3mm )

Filler rod : AWS.A5.10 ER1100

Process : TIG

Current : AC HF

Eletrod : Pure Tungsten 2.4mm diameter.

Welding position : 6G

Type Joint : Square Butt

regard
sani

[Tex]

I was always taught you weren't supposed to get 100% penetration with aluminum. Maybe because of cracking or contamination on the back side of the weld. Are you in school? What's the aluminum tube for?
Good Luck!

[handirod]

We only have a couple of places in our Refinery that has aluminum piping under high pressure. I have actually never tested on that particular weld procedure because we never modify it now, but before becoming a rig welder I was a pipe fitter & I remember helping a rig welder make some aluminum welds that were x-rayed. The only trick I remember on making a full penetration x-ray weld was bevel both ends of the piping to 35 degrees (we had a machine shop do this for us), don’t put a landing on either end & leave a wider space then you would use on carbon steel piping when making your root pass. I don’t remember if we had a positive supply of argon on the inside of the pipe or not during root pass. I’m thinking we would have had too…? We also rolled out every weld that we could to minimize any position welds!!! I can dig up that weld procedure if you need it, just let me know. So in short, yes, it can be done, but it will take time & money to do & to do it right. Hope that helps you… Rodney