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Thread: cryogenic treating

  1. #1
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    cryogenic treating

    This question could probably go in the general forum, but since the term was mentioned with regard to turning tools, I'll toss it out here.
    Would turning tools benefit from cryogenic treatment just by dunking in a super-cold environment?
    A lot of farmers have semen tanks filled with liquid nitrogen. I sold mine a couple years ago. It would be easy enough, especially with turning tools, to just put into the tank for a minute or two.
    Would that be good or useless?

  2. #2
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    Can't answer your question Frank, but if you try it, don't bang the chisel on anything until it has come back to temperature. We played with some stuff when I was in the AF and I seem to recall shattering a piece of steel after dunking it in liquid nitrogen.

  3. #3
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    My understanding is that there is a bit of discussion over cryo treating. Many people in the knife making field advocate it, however there doesn't seem to be any empirical data to support their contention that it "really" improves the process. IIRC, Ron Hock offers treated and non treated blades. For the added cost, especially on a turning tool, I think I would forgo it, but would consider it for a well crafted hunting knife.

  4. #4
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    Cryogenics is a complicated process...

    Hello Frank,

    I wish it were that easy! Unfortunately, you cannot achieve the benefits of deep cryogenic treatments by soaking a tool in liquid nitrogen for a few minutes. Deep cryogenic treatments do not expose the material to the liquid, only the gas. The process of deep tempering is achieved over a long period of time and requires a computer to achieve the maximum benefits the process can deliver. I recently completed a three and a half year test of cryogenically treated woodturning and woodcarving tools in my studio. I'm familiar with the process, so I will give you a snapshot of a typical (may vary based upon material being treated) deep cryogenic treatment cycle:

    A standard deep cryogenic cycle consists of several steps, each "stage" or (ramp) is carefully monitored by the computer.

    1.) The initial procedure is called a ramp down. This will bring the temperature of the part being treated down between -300F to -323F over a six to ten hour period of time. The slow ramping is designed to prevent thermally shocking the part. If you simply dip a part in liquid nitrogen, you can create a temperature gradient that can lead to stresses in the surface of the metal as it reacts to the sudden change in temperature. This can lead to cracking on the surface.

    2.) The second procedure is called soaking. Typically, this will last between eight and forty hours, with the piece being exposed to the nitrogen gas at -300F to -323F. This is the point where things are starting to change in the metal (like the precipitation of fine carbides and making a stronger crystal structure) and it takes time.

    3. The next procedure is called ramping up. This brings the temperature of the part back to room temperature over a period of eight to twenty hours. This must be done slowly to prevent thermal shock and cracking.

    4. Next up is a temper ramp up. This slowly ramps the temperature up to a preset level over a specific period of time, much like the tempering process that you would use during quenching and tempering in heat treating. Typical temperatures reach between 300F up to 1100F, depending on the specific metal and the metals hardness.

    5. Lastly, we have a temper hold to complete the process. This insures that the tempered part has received the full benefit of the tempering cycle. This will last around three hours, give or take - depending on the thickness of the part. Some pieces may require several of these holding cycles.

    As you can see, it's a long and complicated process. However, it can do magical things to many different types of materials. Take care and all the best to you and yours!
    Better Woodturning and Finishing Through Chemistry...

    Steve Russell
    Eurowood Werks Studio
    Professional Studio Woodturner

  5. #5
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    Very interesting reading Steve, thanks for the snapshot

    Frank, I know it works, they use Cryno on racing cage and bike parts, makes all the difference in the world, it is not cheap, but at those levels it is worth it, and if it did not work the race teams would drop it like a hot stone.

    Is it worth the extra money for the average turner?

    Well, I can only speak for myself, and I'd say no, but for a pro who spends all day in front of a lathe, extending the working time on a tool from say 5 minutes to 20 or 30 minutes, yeah, I could see that being worth the extra cost, as the tool would last longer, and you would up your production by turning more and sharpening less.

    Cheers!
    The pessimist complains about the wind; the optimist expects it to change; the realist adjusts the sails.
    William Arthur Ward

  6. #6
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    Steve, thanks. You explained it well. I was just supposin'
    Why can't anything be simple?

  7. #7
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    Quote Originally Posted by Frank Fusco View Post
    ...
    Why can't anything be simple?
    If it was easy, everybody would want to do it.

    Thanks for the write-up, Steve. You answered several questions I've had about cryro treatment.
    When the going gets weird, the weird turn pro. - Hunter S. Thompson
    When the weird get going, they start their own forum. - Vaughn McMillan

    workingwoods.com

  8. #8
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    steve, what, if anything is to be gained by treating say..o-1 steel over using m-2 or even m-42? is there some transformation that takes place that makes cryogrenic treating preferable to changing steel formulations?
    [SIZE="1"] associated with several importers and manufacturers.[/SIZE]

  9. #9
    Hi Frank.

    Currently there is a discussion on cryogenic treatment of tool steel over at Wood Central. I learned a lot about what is OK and what is better. You will probably find it interesting. It doesn't deal with turning chisels in particular, but I think what works for a plane iron can be applied to a turning chisel.

    With the blessings of Bishop McMillan , here is a good reference that appears on the WC site.
    http://www.metalscience.com/techinfo_ASM.php . It is worth looking at, IMO.
    Last edited by Ken Garlock; 02-17-2007 at 03:43 PM.

  10. #10
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    Thanks for the cryogenics summary Steve!

    Can the procedures you described be applied to any type of hardenable steel?

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