Cryo-tempering brake rotors

[John Hofstetter <hofs@domain.elided>]

>Steve:
>
>Your really going to get Hofstetter going on this. He wants to be
>cryo-tempered so he can come back and haunt us all...............
>
>Actually, he has mentioned the process before as a way to "de-brittilize"
>and stabalize certain parts that are subject to temperature extremes such
>as brake rotors.
>
>Pandora's box is officially open. What does everyone say?
>
>Tom H.

It's true, the part about brake rotors. I don't know about the rest of 
you, but for me, probably mostly because I pull a fairly heavy trailer, 
my front rotors tend to get hot, and then they warp as they get hot. 
Obviously, this is because they, when they are turned have built in 
stresses in them, that cause them to warp when hot. If these stresses are 
relieved, then they can get hot, expand, and return to being the same as 
they were before. Cryo-tempering works on guns because it relieves these 
stresses in the barrel metal. Rotors are small enough that cryo treating 
them shouldn't cost a lot, and it seems logical that it would extend 
their life many times over what happens now with having to have them 
resurfaced every 30,000 miles or so. I would want to cryo-temper a good 
used set and have them turned before putting them on the car. This makes 
more sense to me than having a new set cryo-tempered and expect the 
machined surfaces not to warp some from treatment. I don't know that the 
low temperature would cause some warping through stress relief, but it 
seems that this would happen.
John H.