Super Jet Factory Pipe - Cracking?

[Midlake Crisis]

I bought a used limited pipe a couple years ago that had the chamber welded in a couple of spots but was tight when I bought it.
Since then it developed new cracks two more times, both times I had them welded and ran it, the third time I just bought a NIB pipe and it has been good.

Any ideas on what might cause the old chamber to be susceptible to cracking? Anything that can be done about it?
I am deciding whether or not to have it welded a 3rd time to use in a new build, or if I should just mount it in the shop as a decoration.

 

[snowxr]

Heating the aluminum during welding can soften (anneal) it to the point where it is prone to crack from vibrations. Having a repaired chamber re-heat treated might work to prevent future cracks - but only to some extent. Aluminum can only stand up to so much flexing and vibration before it fails, so heat treating can only do so much.