Friday, January 16, 2009

Cool it for now

clipped from www.straightdope.com

Can cryogenic cooling miraculously improve car parts, sports equipment, and musical instruments?



January 16, 2009

Dear Cecil:


I've been hearing a lot lately about miraculous improvements in auto engine parts, golf balls and clubs, razors, and even brass and stringed musical instruments, all by subjecting the object in question to a deep freeze of 300 degrees or more. Is there any solid evidence for this? Sounds like pseudoscience to me.





Cecil replies:


I wouldn't go that far. As a former high school science fair geek, I've got a soft spot for cryogenics, as the science of deep freezing is known. Anything that lets you hammer rubber nails into a two-by-four with a mercury mallet — I'm telling you, with the right crowd, a stunt like that kills. More seriously, cryogenics has been the subject of continuing research for over a century. The federal government bought a hydrogen liquefier in 1904; to this day NASA operates a Cryogenics Test Laboratory at the Kennedy Space Center in Florida. In short, cryogenics is a legit field of study. That doesn't mean a cryogenically treated club will help you play better golf.


Deep freezing produces detectable improvements in performance mostly when metals are involved. (I don't claim it won't help other materials, but research into cold-treating of composites and such, from what I can tell, is less well advanced.) That's because of the quirky process known as crystallization. Depending on what you do while working it, a metal can crystallize in varying ways, yielding products with markedly different properties.


One thing that determines what kind of crystals you end up with is how much and how fast you cool the metal after you heat or melt it (quenching a sword is a good example). As the metal sheds heat, its crystal structure changes, then ultimately stabilizes, usually well before you reach room temperature. But if you keep cooling the metal to exceptionally low temperatures, like -300 degrees Fahrenheit, you can force the crystals to change shape again, sometimes to advantage. Done right, some contend, deep freezing can make metal harder while reducing residual stresses. Result: a more abrasion-resistant, less brittle part.


Or so goes the theory. How well it works in practice is debatable. Cold treatment of some types of dental drills, for example, made them cut better and faster through teeth, but other types didn't show any change. More to the point, another study noted that while the treated drills were slightly harder and thus presumably more wear-resistant, in practice they worked no better than the ordinary kind.


As far as golf gear goes, Nicklaus Golf Equipment once offered an assortment of drivers with cryogenically treated metal faces (the "Airmax" line) but stopped making them several years ago and doesn't currently deep-freeze any of its clubs. When we contacted the Nicklaus folks, they told us the reason they discontinued cryogenic treatment wasn't that it didn't help — they insisted it did — but that USGA rules changes in 2004 allowed bigger club heads for drivers, giving them an alternative route to improved club performance. I take "alternative" here to mean "simpler" and likely "cheaper." In any case, the day of cryogenic golf clubs seems to have come and gone. An informal survey of golf shops found that none offered cold-treated clubs from well-known makers.


Turning to musical instruments, we see the same does-something-sometimes-but-so-what pattern. For trumpets, a couple of limited studies showed no real difference between cryogenically treated and untreated instruments. Stringed instruments seem to be a different story. My assistant Una contacted Chen Jer-Ming, a graduate researcher in music acoustics at the University of New South Wales in Sydney, Australia, who studied the effects of cryogenic treatment on steel guitar strings. He found cooling the strings to -300 F for 30 hours produced subtle but unmistakable changes in their crystal structure. Afterward the strings showed slightly increased strength, 15 percent less stretching over time, and 35 percent greater stiffness, meaning they might be louder, break less, and require less frequent tuning. The drawback, according to Chen: they produced a tinnier tone. In other words, you wound up with strings that lasted longer but sounded worse.


Conclusion: Cryogenic treatment may yet yield some useful products, but right now I'm not seeing much.

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1 comment:

Frederick Diekman said...

The Cryogenic Society of America sent me a link to your blog. CSA is a non-profit technical society serving all those interested in any phase of cryogenics, the art and science of achieving extremely low temperatures — almost absolute zero. Their web site is www.cryogenicsociety.org/. I am the co-chairman of the ASM Cryogenic Processing Sub-Committee of ASM International. ASM International is the professional society of metallurgists and materials scientists. Their web site is at www.asminternational.org. Both of these organizations are extremely well known and respected in their fields. Both recognize cryogenic processing of materials as a legitimate, useful and valuable method of altering the characteristics of materials.

I wish to thank you for doing some research and finding that cryogenics is not a pseudo science. Cryogenic processing, (also called cryogenic treatment or sometimes incorrectly cryogenic tempering) is a thoroughly tested and effective process with many uses. Tests have been run by major universities, national laboratories, and by individual companies. NASA, the US Army, Illinois Institute of Technology, Los Alamos National Laboratory, Purdue University, University College, Dublin Ireland, and many others have tested the process and found it works.

Your explanation of what happens to metals when they are cooled is an OK explanation when trying to communicate with non-metallurgists. It is good that you note that metals are crystals and that you can change them by using temperature. I’ll only say that it is quite a bit more complicated than that, but changes in the atom to atom relationship is what is probably happening in cryogenic processing.

One of the biggest uses is for treating of brakes used on cars and trucks. Independent laboratory tests prove that cryogenic processing increases the life of automotive brakes up to four times. The US Postal Service uses cryogenically treated brakes as do many police and fire departments. As brakes are a major repair cost, there are considerable savings involved. Porsche uses this process on cars used in endurance racing and has been able to complete hour races without changing the brake rotors, which saves considerable time in the pits.

Speaking of racing, valve spring manufacturers are using cryogenic processing to increase the life of their products. A six-time increase in valve spring life is not unusual. I personally know of racers who use treated springs for the full season of racing where their competition puts in a new $400 set every race. This effect is so profound that my company is assisting a doctoral student in her research to find out why. Jerico Performance Products (maker of the transmission that has won more NASCAR races than any other) uses cryogenic processing to increase the life of their products. My company alone has treated parts on over half the starting field in any NASCAR Sprint Cup, Nationwide Series, or Craftsman Truck series race.

Other uses abound. For instance, GKN company is a major OEM supplier of automotive components. They did research in conjunction with University of Trento in Trento Italy and found that cryogenic processing cut their tooling costs in half. Sunbeam Corporation uses cryogenic processing to increase the life of hair clipper blades. Manufacturers of plastics pellitizing knives have found tremendous life increases. Mining companies have found tremendous increases in the life of bits used to cut rock. Companies that machine metals save considerable money by having cutting bits, drills, taps, hobs, etc. treated. Newspaper printers save tremendous money by buying paper cutting blades that are treated.

In the musical field, many manufacturers of high-end audio components use cryogenics to increase the sound quality of their products. Do a web search for “cryogenically treated audio” to see for yourself. Treatment of vacuum tubes has been shown by research and by practical use to increase sound acuity and tube life. CD’s sound better when treated. I know, because I’ve heard the difference in a blind test. Treated guitar strings are available in most music shops. My colleagues and I have processed musical instruments for professional musicians who absolutely love the process. There is a piccolo company that not only uses the process to make their production process easier, but has found better sound as an addition.

I could go on and on with uses that are in production daily. Let’s not bore people with this. This is a great process. More research needs to be done, but it could save manufacturers great amounts of money while increasing the quality of their products. On reason we do not see more use is the silly “if we make it last twice as long, we will sell half as many” attitude of many companies. Experience shows profits on treated items increase and the sales drop is mainly experienced by company’s competitors.

Thank you for your thoughtful research on the subject. I hope that I have been able to point out some of the uses of the process in common use at this time.

F. J. Diekman
Controlled Thermal Processing, Inc.