Welding 2024-T3

[KirbyWan]

Howdy all,

Once again someone has insisted that we can weld 2024-T3 and showed me the section of the Welding manual D17.1 where in a table it indicates for 2024-O D - no valid welding process, but for 2024-T3 (and others) it indicated C - Limited weldability due to crack senstivity... To me a C - limited weldability means unweldable. The only process I can think that can weld 2024 is friction stir welding, which is not really feasable.

So my question is, what does the limited weldability due to crack sensativity mean? Is it o.k. to weld non-structural pieces (in which case why use 2024)? Is there some maximum weld length or a special post weld heat treat process? Does it mean if you have the greatest welder in the world then it's o.k. for him to do it? What are they trying to convey with the limited weldability?

As it is, I said that they can not weld a material unless it is A or B on that table, but the more I know the better I am as an engineer, so please share you thoughts about this. Thanks for helping.

-Kirby

Kirby Wilkerson

Remember, first define the problem, then solve it.

 

[rerig]

Regulation:
FAA Advisory Circular 43.13-1B, Ch 4, Para 4-89, d, "AIRCRAFT PARTS NOT TO BE WELDED".

d. Nos. 2024 and 7075 Aluminum. Do not
weld these two aluminum alloys (that are often
used in aircraft construction) because the heat
from the welding process will cause severe
cracking.

Experience:
Having worked at a Repair Station that did welding on 2024 & 7075 parts, I can attest that these parts WILL crack within a few months. We worked on some "Non-structural" cargo bay lip protectors. They would get welded and then several months later would be returned with the damage about 3" larger than original. Eventually they would get scrapped due to the size of the damage.

Sure it CAN be welded...but should not be welded.
Rerig

 

[KirbyWan]

rerig,

Great reference. I'll pull that one out the next time they say they can weld 2024. The particular application they are going on about this time are support angles where the holes are misdrilled. They want to weld up the holes and then redrill them. I said no.

-Kirby

Kirby Wilkerson

Remember, first define the problem, then solve it.