Welding of 6160 T6 Tubing 3

[rlangdon]

We are getting well over 50% rejection rate on our 6160 T6 .500 O.D. X .028 Wall tubing. Most of the rejection is due to porosity. This problem has been going on for years now and no solution has been found. Our 30 year welder seems to think that the hardness has no effect on the quality of the weld. New fixturing will be developed if no other solution comes forward. Any ideas? Thanks.

 

[rlangdon]

Sorry 6061 T6. You know what I meant.

 

[metengr]

rlangdon;
What is the welding process you are using?

 

[rlangdon]

We are manually TIG welding. The tubing is fixed, and the welder rotates around the joint.

 

[metengr]

ok. There are several possibilities for porosity;

1. Check your gas supply. I presume you are using a welding grade of Argon gas. Depending on usage, I have seen problems with gas contaminants that could result could in porosity of the weld during solidification.

2. Make sure the weld joint is clean of oil, obvious surface oxides and other contaminants PRIOR to welding. Aluminum oxide can absorb moisture. During welding, hydrogen that is produced from moisture is absorbed by the weld metal resulting in porosity.

3. Aluminum is readily weldable by the GTAW process. Make sure you are using an AC power setting to provide for cleaning action of the aluminum oxide during welding.

4. You might want to check the condition of the welding electrodes. Bare wire that is laying around the shop can develop an oil film that will cause porosity. Wipe down the welding electrodes before using.

 

[deanc]

Totaly agree with metengr and would add.

1.May wish to try helium.
2.Zicronium tungstens. (zirconiated)
3.Back purge
4.Clean gloves for the welder
5.Clean your parts with acetone before you wire brush and Stainless steel wire brush only. Carbon steel is a no-no.
6.Make sure your gas flow is not to high.

 

[metengr]

Good info by deanc -