Appropriate Cryo Methods

theWeatherman

Well-Known Member
So I have seen a couple different ways to do cryo on say CPM 154CM. I have heard using ETOH and Dry Ice, Acetone and Dry Ice, Liquid Nitrogen, and just Dry Ice blocks.

Can you get the correct results by just placing the blade between two blocks of dry ice for a Cryo Treatment?

-Brian-
 
Brian, you can do "cold treatment" (-100) with dry ice and acetone in a poly cooler. Crucible calls for dry ice treatment in their data sheet, so I think you can achieve a "correct" or "acceptable" result doing this, but maybe not a "best possible" result as could with LN2. I use LN2 on all my alloy tool steel blades, just to get a little extra austenite to martensite conversion, and do 3 temper/cryo cycles. The practical results for a knife in use may not be realized but becomes more of a sales point. I have a lot of links, data, history, known patents, etc etc on Cryo if interested let me know.
 
I am interested, sent me what you think is appropriate.

Can you tell me where you get your stuff in town and what you hold your LN in? (Since you live just down the way from me)
 
Im pretty new at this Cryo stuff.. If you are putting together a email with some info Paul, can you add me to it?

I store my LN2 in a 34 liter Dewar and have found a local welding shop that has a supplier deliver the LN2 per our request.

Thanks, Have fun and be safe!
Randy
 
LN (liquid nitrogen) can usually be purchased at a welding gas supply store.

If you use dry ice, also often sold by welding gas supply stores, consider using non-toxic anti-freeze instead of highly flammable acetone. Simply putting the knife blank under dry ice is going to work just fine also.
 
Randy I'll add you to a PM to Brian on what I have.
Boss is right, the Welding shops have LN2... Brian in Ft Collins, Airgas on Link Ln is closer but price is higher.
 
Would it be possible to also be placed on that PM. I had just sent Kevin Cashen an email on the subject?
 
Just to add on to the above, LN2 has different effects on steels that dry CO2. Both convert retained austenite. LN2 also conditions the martensite, promoting precipitation of fine and numerous carbides upon tempering.
 
Just to add on to the above, LN2 has different effects on steels that dry CO2. Both convert retained austenite. LN2 also conditions the martensite, promoting precipitation of fine and numerous carbides upon tempering.


That is the first time I have heard that and I have done some research on cryo. Could you point me to a reference on that? I would like to see some more on that.
 
Just to add on to the above, LN2 has different effects on steels that dry CO2. Both convert retained austenite. LN2 also conditions the martensite, promoting precipitation of fine and numerous carbides upon tempering.

The number one thing to look at on any write up of a cryo study is if it was done by people who sell cryo services to get an idea if you are getting unbiased and objective data, in many business that is called a conflict of interest. I have seen but a handful of studies that seemed to have no such conflict, and those rare few very often show much less dramatic results than the ones done by folks who have a financial interest in it having dramatic results. This is especially true of the material regarding eta carbide formation. Retained austenite conversion you can take to the bank, many of the other claims are in a gray area.
 
It's like asking a Barber if you need a trim. They will sell you a haircut every time....getting legitimate research data on cryo is really difficult.
 
That's not to say that there isn't some interesting things going on, and there is no topic that I try to keep more open mind about, as it is intriguing, but some of the marketing has been over the top. I have seen claims of as high 600% improvement from freezing things, I don't think the hardening process itself can claim that; these folks aren't doing the subject any favors. I have some inside information that makes me personally skeptical of the eta carbide thing, but the concept of lattice reordering and improvement I think is very interesting and worth a look.
 
The articles I have are in print. If anyone wants them, I can pdf and email them. I'll post the references and maybe someone can find them again on line.
 
The articles I have are in print. If anyone wants them, I can pdf and email them. I'll post the references and maybe someone can find them again on line.

I would like to see them. I believe cryo does some things that are beneficial in certain circumstance and would like to read up a bit more if I could.
 
I have .02 to add.
I was using LN and the welding supply I was dealing with for some reason decided not to sale LN to anyone in small amounts and another knifemaker in the same town had a 32L LN tank and they would not fill it ether , so to get it I would have to drive 50 miles oneway to get it . So I went to dry ice and acetone and I had to temper at little higher temp to get the RC that I wanted . This was a suprize to me . I always wanted to ask someone about that but never did.
 
It's like asking a Barber if you need a trim. They will sell you a haircut every time....getting legitimate research data on cryo is really difficult.

Ya, but Boss - you do need a haircut. <JK>

But my point is that just because someone offers a service doesn't necessarily mean they are trying to mislead you. Maybe they are just explaining why they believe in what they offer, and if the claims aren't ridiculous, that can be done with good intent and even credibility. Its good to consider bias when advice is give - but don't dismiss the advice simply because of it.
 
Ya, but Boss - you do need a haircut. <JK>

But my point is that just because someone offers a service doesn't necessarily mean they are trying to mislead you. Maybe they are just explaining why they believe in what they offer, and if the claims aren't ridiculous, that can be done with good intent and even credibility. Its good to consider bias when advice is give - but don't dismiss the advice simply because of it.

good and fair point. Everyone isn't on the hustle to make a quick buck in the cryo business. But... there has been a lot of shady claims made about cryo treatment and a healthy dose of skepticism isn't always a bad thing...
 
Just to add on to the above, LN2 has different effects on steels that dry CO2. Both convert retained austenite. LN2 also conditions the martensite, promoting precipitation of fine and numerous carbides upon tempering.

Yes, Please post any links that that you have? It's my understanding that it's the cold temp, Not the way you get it that cold?

Please share this with us.

Laurence

www.rhinoknives.com
 
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