I'm thinking about getting my CV cages cryo treated. A lot of people swear by it, but most of the scientific data I've seen has been from the people that offer the service (of Course). There are a lot of smart guys in here..What say ye?

I think so. I've seen it work on monster hp (1000+) BBC boat motors that had a problem with breaking forged cranks until they went cryo on the cranks and rods. No more breakages until they got one up to 1500hp or so.

I was intrigued by your question, so I did a Google search on "cryogenic treatment of metals". It wouldn't be fair to you or the authors to try to summarize the various articles. One consistent thought that I did find was that the greatest advantage is in reducing wear, hardly the issue with CV joints. Another statement that stood out was that the process is of the most value when done before grinding and polishing.

I would suggest that you spend a couple of hours searching and reading.

I also did a Google search, but for Cryogenic treatment of CV joints. There is more out there than I care to read, but most say it's a good thing.

I say its worth a shot...I'll call tomorrow and see how much.

I'd say it's worth it, just to get all your austenite converted into martensitic stuff, not to mention the precipitation of the eta-carbides and the internal stress relief. It's embarassing to have RA (retained austenite) and unprecipitated eta carbides and unrelieved internal stress. <img src="/forums/images/graemlins/evil.gif" alt="" />

The times I did a search I never found anything that was peer reviewed. Not saying it does not work... Just saying the info was not well substantiated.

After two weeks of testing electronic materials at -55?C I know cold can do some funny things to materials ( so far none of them have been good).

I know I hear a lot of anecdotal info on cryo...

>>>*I first heard of cryogenics back in the early 70's. That was interesting. I have done a lot of metals heat treating, things like connecting rods in an oven at 450? for 8 hours. Then we left them in there until they cooled slowly to room temperature which usually took another 3-4 hours or so.

The process hardened steel connecting rods or I should say we thought so. We did that to reharden the beams after grinding off all flashings and polishing them. Connecting rods are shot peened to about .125 ARC which work hardens them, grinding removes that.

The only messing around with cold temps I ever personally did was with the racing tires. During the Winter season we stored the used ones in a big old deep freezer. About as cold as we could get was around 30?F below zero, one long ways from Cryo temps.

Tires react because the rubber has lighter volitiles that dry out when stored and that did work. When the track officials tested the tires for chemical softeners, our used tires always tested as brand new which got us dirty looks from the competition and accusations of using "something" on them. But they also had sniffers, ours always passed too.

MHO is that extreme low temps have quite a serious effect on many materials...*EB

Correct me if I'm wrong (probably am), but I thought the long cooldown softened the metal, whereas quenching it in cold water made it hard, but brittle. I recall in high school engineering class (welding/drafting) the teacher talking about modifying something in their cars transmissions back in the 60s that was a hardened piece. He said they'd heat it red hot, and then pack it in oiled sawdust to slow the cooldown. It was soft enough then to drill/cut/whatever they did, and afterwards it would get re-heated and quenched to re-harden it.

A long slow cooling process anneals the metal by allowing the metal crystals time to grow larger. A fast cooling freezes the structure, keeping a finer structure.

Work hardening decreases crystal size by mechanically dislocating them.

Shot peening dislocates and puts the surface in compression.

The finer structure has more dislocation points, making it harder to permanently deform.

Lots of other details... Its been a long time.