Posted by: craw
It would be cool to see a more efficient way to build a bike out of 7075 rather than Pole's way, which seems like a lot of added effort. Does 7075 need to be heat treated after this new process? Can someone with some related knowledge comment on that - just because 7075 can be welded can this process realistically be used for making bikes?
From what I remember, and can look up on google, essentially what happens when you weld metal together, because of the intense heat and therefore expansion and following contraction of the material, there's more tension in the material close to the weld. And if I remember correctly the crystal structure changes as a result of the high temperature (edit: not sure about this). Essentially you warm the metal to relax the structure and make it less susceptible to breakage.
So I guess the answer is: no, but you lose a fair amount of the materials strength and resiliency near the weld area. But also yes, because you don't want your frame to crack.
As far as strength is concerned, 7075 is (on paper) close to steel, but still off by (done in my head) about 20%, depending on the alloy. So depending on how thin you would have to make the tubing, the benefits could be negligible in the end.
But I'm just spitballing... I'm no material science guy (and my teacher was terrible).