so whats the verdict on Cryo?

[Science Abuse]

the technique has been out about a little while now, I'm sure some on here "knows a guy who knows a guy" or read soemthing in reguards to weather or no cryo treatment is actualy worth the time and money.

Anyone hear anythang?

[Guest Ranger_Man]

 

LUCY YOU GOT SOME SPLAININ TO DO!!

[SupraGlue]

Everything I read from the Supra road racers indicates that it extends rotor life. Several of them swear by it and won't use non-cryo rotors anymore.

 

I have never read a real engineering breakdown of why it works, however.

 

Cold fusion mumbo-jumbo, or high-tech mojo? Try it and let us know. tongue.gif

[Guest badmuthrfkr]

After that NASA track day, should I have to replace my PowerSlots, I will most likely go back to stock rotors cryo'ed.

 

Just stick yours in the freezer and see if it helps first.

[Nitrousbird]

Some of the 4th Gen F-body guys have been doing it to the output shafts on the T-56's (at least the guy's w/ traction), since manuals shock the driveline a lot and the output shaft will go if the clutch is super grabby and you get great traction w/ decent power (with a strong rear-end of course).

 

But, even then, it hasn't been proven. There are also guys who cryo treat the Viper output shafts when they convert to those.

 

I'd like to see if there have been any proven gains on doing it to BLOCKS. I could see there being some strength gains in doing that.

[slow4now]

Cryo treatments basically re-align the molecules in the part that is being treated so that they are more uniform. So instead of having some weak areas where the material may not be as dense, it makes them less porous thus making them exceptionally stronger.You could say it spaces the molecules more evenly. I've never read anything but good about it. It would benefit any metal part, I think it would help cast parts moreso than forged parts though. So Cryo treating a block would be a good idea, it would be a lot less likely to suffer a stress fracture do to weak spots.

 

[ 15 December 2002, 10:09 AM: Message edited by: bigbabyjesus ]

[SupraGlue]

Found this on a site that sells cryo treatment. Take it with a grain of salt, but it explains in a metallurgical sense what the cry treatment is attempting to achieve:

 

http://www.300below.com/cuttingtool.htm

 

"Chilly Changes

Slowly cooling a tool steel to deep cryogenic temperatures and soaking it at this low temperature for several hours changes the material's microstructure. Almost all of the austenite (a soft form of iron) retained in the steel after heat treating is transformed into a harder form, martensite, by deep cryogenic tempering

 

A second result of a deep cryogenic "soak" is the formation of fine carbide particles, called binders, to complement the larger carbide particles present be­fore cryogenic treatment. (Depending on the alloying elements in the steel, these particles might be chromium carbide, tungsten carbide, etc.)

 

One recent study by Randall Barron, Department of Mechanical Engineer­ing, Louisiana Polytechnic Institute, Ruston, LA, looked at how the changes brought about by cryogenic treatment affected steel's ability to resist abrasive wear. This type of wear occurs when a body penetrates and gouges a material's surface. The gouging body may be a surface asperity on a mating part, a free­abrasive grit particle from an external source, or an internally generated wear particle

 

The Barron study found that the mar­tensite and fine carbide formed by deep cryogenic treatment work together to reduce abrasive wear. The fine carbide particles support the martensite matrix, making it less likely that lumps will be dug out of the cutting tool material dur­ing a cutting operation and cause abra­sion. When a hard asperity or foreign particle is pressed onto the tool's surface, the carbides further resist wear by preventing the particle from plowing into the surface.

 

Some of these benefits may be achieved through standard tempering, which also transforms austenite into martensite. But standard tempering may not bring about a complete transformation in some tool steels. For example, 8.5% of an O-1 steel remains austenite after it is oil-quenched to 68'F. If M- I is quenched from 2228° F to 212° F, then tempered at 1049° F, the retained auste­nite is 11 %.

 

Additional improvements in tool per­formance can be achieved if this retained austenite can be transformed to martensite. As Barron's study has confirmed, adding a cryogenic step to the treatment process does just that.

 

In the chart accompanying this article, data drawn from another study of treated metals by Barron indicates which samples exhibited improved abrasive

 

Critics

In addition to examining cryogenic treatment's effects on austenite transformation, Barron also looked at other, less obvious metallurgical changes. His data helps answer those critics of cryo­genic tempering who doubt the effec­tiveness of a process that imparts so few visible changes to the metal. These critics say heat treating already changes 85% of the retained austenite to martensite, leaving only 8% to 15% to be transformed by deep cryogenic tempering. Using the process to produce such small results is inefficient, according to the skeptics.

 

These observations are accurate as far as they go. But they fail to take into account the fact that metals subjected to deep cold develop a more uniform, re­fined microstructure with greater den­sity. The particles that are formed through the precipitation of additional microfine carbide fillers take up the remaining space in the microvoids, resulting in a tool steel with a much denser, coherent structure that improves wear resistance.

 

Metallurgists have known that cryo­genic tempering has this effect, but they may not have realized the extent to which the microstructure changes. Research­ers in a study conducted at the Jassy Polytechnical Institute in Rumania used a scanning electron microscope equipped with an automatic particle counter to identify and quantify these smaller particles. Through this examination they found that cryogenic tempering creates a significant change in density through­out the tool

 

Some people acknowledge the ben­efits of cold tempering, but they ques­tion the need to use temperatures below -110° F. A review of the data from the Barron study, however, shows that some tools, at least, perform significantly bet­ter after processing at-310° F than they performed after -110° F tempering. Among cutting tool steels, for instance, the wear resistance of M-1 HSS was almost one-and-a-half times the wear resistance of the untreated material after a-110° F soak. After a-310° F soak, the steel exhibited two-and-a-quarter times the wear resistance of the untreated material. T-1, the traditional tungsten HSS, went from a little under one-and­a-half times the wear resistance after a -110° F soak to one-and-three-quarters the wear resistance after a -310° F treat­ment.

 

It may be concluded from these tests that treatment at -110° F does improve wear resistance, but deep cryogenic treat­ment at -310° F improves wear resis­tance much more. To allow time for the very fine carbide particles to form and the retained austenite to be transformed into martensite, a long soak at deep cryogenic temperatures is necessary."

 

Ultimately, it would seem to come down to a cost-benefit analysis. Does the extended wear life of the part(s) in question justify the cost of the cryo?

 

[ 15 December 2002, 02:48 PM: Message edited by: Stolen UFO ]

[Mallard]

Originally posted by bigbabyjesus:

Cryo treatments basically re-align the molecules in the part that is being treated so that they are more uniform. So instead of having some weak areas where the material may not be as dense, it makes them less porous thus making them exceptionally stronger.You could say it spaces the molecules more evenly. I've never read anything but good about it. It would benefit any metal part, I think it would help cast parts moreso than forged parts though. So Cryo treating a block would be a good idea, it would be a lot less likely to suffer a stress fracture do to weak spots.

Yes, thats what cryo people say happends, but it has not been proven. I talked with some metallurgists at work about it a few weeks ago and this and the concensess was that changing retained austinite to martinsite was the only PROVEN benefit. Some of cryo treatment is still seen as a black art by metallurgists. There are people who cryo treat everything from musical instruments (they claim better tone) to pantyhose (They say then don't run). But nobody can prove why that happens.

 

One theory for engine blocks: When building a motor a lot of people will say get an older "seasoned" block. That block has gone through a lot of expansions and contractions and its dimensions would stay fairly stable. Cryo treating may accelerate this process on a new block and make it better for machining. That and the theory about lining up the molecules seem plausable to me, but has not been proven.