I for one, *am* joe . Brownian motion is the random movement
of molecules in a liquid or gas. There is no brownian motion
in a solid.
Joe

 

Joe:

I agree, post cryo treating is 100% bunk. Now, cryo drilling is not. Cryo drilling (keeping the rotor super cold while drilling) avoids any heat related stress concentrations and does produce better rotors. Once they’re drilled or slotted, too late.

 

i'm not familiar with cryo drilling, but the idea of making sure
work-related heat is removed efficiently during machining is
pretty standard. Typically during machining, the piece is
continually flooded with a fluid to keep the piece cool. Machine
tool bits stay harder and sharper if kept below the phase-shift
temperature where steel separates into austenite and
martensite.

 

Joe, yep:

Usually normal cutting cooling fluid in your typical CNC will not keep the part cool enough to avoid localized damage, thus the cryo (or real cold) solution being a much better option.

I know it is possible but have never heard of anyone growing brake rotors like tubine rotors where you have only ony huge crystal. I wonder how much better they would perform if single crystal rotors were cryo drilled afterward?

 

I will now reveal what a nerd I am. I have often wished I
had an industrial capacity for generating monocrystaline
metalic parts. I don't think it's currently possible. The drilling
would be non-trivial due to the strength of such a part...
It would be akin to drilling into diamond instead of graphite.
Joe