dc70

Close, it is actually −459.67 °F or Absolute 0 Kelvin.
Here are some interesting facts:

Kinetic theory
According to kinetic theory there would be no movement of individual particles at absolute zero, and thus any material at this temperature would be solid. This contradicts experimental evidence. A more practical definition of absolute zero is as the temperature where no further energy may be extracted. For the case of free atoms at temperatures approaching absolute zero, most of the energy is in the form of translational motion and the temperature can be measured in terms of the distribution of this motion, with slower speeds corresponding to lower temperatures.

Cryogenics
It can be shown from the laws of thermodynamics that absolute zero can never be achieved, though it is possible to achieve temperatures arbitrarily close to it. This is the same principle that ensures no system may be 100% efficient.

Cryogenics for high performance parts was popular not too long ago in the motorsports world.
Pistons, Cranks, Flywheels, Cams, Chains, Sprockets, Etc...
There are a few companies out there doing it. Whether or not it actually improves and extends
the life of the parts being treated, I don't know, Some swear by it and and some industry insiders
debate it.

PaulBravey

According to my old text books Nitrogen becomes a liquid at 77K (-321 F?) and a solid at 63K (-346F?). Are you thinking of Helium?

Patriot

Sorry to tell you this, but you are correct, yet incorrect on a couple things. Liduid N2 does get that cold (-400F or something), but I am talking about the process used for stress relieveing the metal in gun barrels. The refrigeration unit only takes it down to -300F.
Second, the process is used after the barrels are completely forged and the breaches, chambers and crowns are machined. The process is done soooo slowly, that the barrel does not warp from the process. That's the whole point of it. It aligns the molecules and fill the micro-gaps in the surface to give the rifling a smoother more accurate surface. Some barrels are honed afterward (by hand in many cases), but only if necessary.

These are of course, moot points, since none of this applies to truing the wheels of a road bike.

white lobster

I remember a long, long time ago seeing a set of service instructions for a set of wheels with Campy hubs that said, in very broken English, "to remove pressed dustcaps, place wheels in pizza oven for 10 minutes."

Not having a pizza oven handy, I was S.O.L.

manual_overide

the heat treating process described above applies to steel. I don't know how it works for aluminum. yes, most steel products go through an annealing step, a cryogenic step, and a final tempering step. I thought I heard somewhere that aluminum was annealed (thus implying that the other steps also take place), but I'm probably wrong

matthewyounkins

Oopsie. I guess I should pay attention a little more...

matthewyounkins

I was saying (from memory) that nitrogen becomes a liquid at something like -410 F. I just looked it up, and it *is* really around -340, like someone else said. Damn memory.

ruppster

Hey, 300 Below is using different units than the ones we designed and built for them. If you see any off white units with a blue gun silkscreen on them, I was involved. Those guys were also doing brake rotors for racecars. Make your disc brakes better (and store your favorite bull's sperm forever) through the miracle of cryogenics.

matthewyounkins

I'll try not to write a dissertation on Materials Science, but...

When there's a stress, whether internal or external, there's a deflection in the part. If you machine the part with this deflection in place, and then remove the stress, the part will return - i.e., warp.

What I think most of the cryogenic people are trying to sell is actually tempering of a material; some of it could possibly be (with steel) changing austenite to martensite, etcetera (martensite is *very* good, especially when tempered).

I believe that cryogenic tempering can work - but it's not the same as stress relief.

tribe3

It' true! They straighten in the freezer, the problem is that they bend again as soon as you take them out

jeff800

I just wrecked my car I wonder were I could get a freezer large enough to get the whole thing in there.

https://www.onecryo.com/

ginger green

Patriot - I just about peed my pants when I saw that you had a link on your first reply - I thought you had posted a picture of yourself standing beside your freezer in some sort of Pose.

Perhaps one hand on the lid, looking off in the distance, shirt untucked - very ocp.

Here is thought - stay with me - I got major hail damage on my van - many of the "dings" worked their way out during the very hot summer months - the metal gets hot on sunny days and the dings become smaller.

On the same note if your wheel is slightly out of align - won't the metal slightly contract in the freezer as it freezes, thus balancing the tension on the spokes...

turkdc

A woman goes with her husband to the Psychologist's office. The doctor asks her what the problem is. "My husband thinks he's a refridgerator." She says.

"That seems to be a pretty harmless delusion" the Psychologist replies, "why are you so concerned about it?"

"It's just at night" the woman says "my husband sleeps with his mouth open and the light keeps me awake..."

dc70

I was referring to absolute zero, where you were a bit off, but you are correct about the Nitrogen.
my bad.

Patriot

Have you ever seen that movie "Predator 2" with Danny Glover?

Actually, I am now thinking about investing heavily in one of those silver insulation suits, and one of those fancy Liquid Nitrogen Super Soakers that Gary Busey was using in that flick when he was trying to freeze the Predator. Too bad he got his head cut off.

I figure, I can just hose down my bike with liquid N2 once a week for complete repairs, adjustments, and a full wash and wax.

Machka 

So ... does that mean ... when I ride outside in the winter with my mountain bike that my rims are busy truing themselves as I ride?

Patriot

In Canada? Yes.

Be careful, you may freeze solid and end up on the side of the road as a bike-sicle.

Machka 

I've had my brakes and gears freeze up! When it gets cold enough, the bicycle turns into a fixed gear!