Aluminum Pre-qualified WPS

[ATSE]

Some very basic questions on structural aluminum welding (90% of our aluminum is 6061-T6, GTAW).

1.One big difference between AWS D1.1 and D1.2 is that D1.2 seems to be missing the chapter on pre-qualified welds. Why is pre-qualified good enough for steel, but not alum?

2. Are aluminum fillet welds of any size pre-qualified, or does a shop need a WPS backed up by qualification tests (i.e. bend tests) just to run a single 1/4" fillet weld? Is this clear in D1.2?

3. Can a shop share their qualification tests with other shops? That is, does D1.2 forbid a welder from using using a WPS created by a third party?

4. An an engineer, is it permissible to allow production CJP welds be inspected visually only (not require RT or UT)? Is this a good idea? No disrespect intended, but I haven't been impressed with the pictures and interpretations I've seen from RT. Seems like a waste of time and money.

 

[Ron]

The weldability of steel is much more predictable than for aluminum. The strength of steel is not significantly affected by welding, whereas with aluminum, it's anybody's guess as to what happens in the HAZ. That's why the lack of pre-qualified joints in aluminum.

As for NDT, unless you have x-ray vision, I would require some level of RT or UT. Make sure the interpretor is an ASNT Level II or Level III, preferably Level III. Further, that interpretation should be concurred by a licensed professional engineer with experience in NDT and preferably Level II or Level III qualified.