Cryo for steel is useless??

Cobalt

Cobalt

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Since we took the other thread so far off topic, which was unfair to the original poster, I figured I would start a new one.

I will quote the final posting in the other thread regarding this:

bearcut said:
And yes, mete is right, cryogenically treating metal does not change anything!

Atoms stop moving at Absolute Zero, {-273 C} At Minus 40, they are moving, {relatively}, slow! Things break, even rubber.

My 2 cents…..
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So is cryo just a useless bunch of crap. For years I was under the impression from many sources that Cryo was beneficial if done as part of the HT with the tempering process. Now there are so many stating that it is just worthless.

So which is it?
 
Would it not be relatively easy to prove cryo effect by testing identical blades - ones with cryo and ones without. See what happens to retention and toughness and so on. I actually think that knife manufacturers have done this. If there was an improvement with cryo why aren't all manufacturers using it? If not, why are some manufacturers using it?
 
The advantage to lower temperatures is less retained austenite. When it comes to knife steel, I am not sure how much of a benefit is derived from cryogenic treatment.
 
Pulled this from the other post.




mete said:
Bors, I am a retired metallurgist and I'm on a number of knife forums trying to educate people ,especially makers, about metallurgy.....
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"industry pretty well accepts ...cryo" That's not true there are many who have found it did not do what was claimed.
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Is it that it did not work or that it just did not work for their application?


I've been through these discussions many times and it's always the same -many claims by cryo companies ,many users who found it didn't work at all , some found little benefit, and no real scientific evidence to explain just what happens.
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How many centuries did it take us to understand heat teating. Yes we new that if you heated steel to a certian temp and then quenched it it got very hard and if you heated it at a lower temp you tempered it which made it not so brittle. But could we "explain" what happened and why.......no.


We had a metallurgist on another forum who works for a cryo company and a member of the ASM Cryo committee.We gave him every opportunity to provide information and he couldn't do it ! Yes cryo reduces retained austenite but that's all we know at this time ... Go to the Makers section and search 'cryo' I won't repeat myself here.
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It sounds like we are at the same stage as the early makers of centuries ago. That is we know something is happening but since we don't understand it we can't scientifically explain it.
 
Without getting really complicated, at the very least hundreds of heat treaters have noticed that an increase in hardness comes after using a cryo treatment, if nothing were happening because the atoms can't move at that low a temperature or whatever the theory is, this wouldn't happen. There are many studies where the focus is cryo treatment, and several makers have done cutting tests with and without cryo, most notably Wayne Goddard in my mind.
 
By the way, while the main benefit of cryo is reducing retained austenite, there are several studies that claim that wear resistance is increased more dramatically after long-term cryo treatment from carbide precipitation. The same studies usually state that toughness is decreased after using long-term cryo as well.
 
Larrin said:
By the way, while the main benefit of cryo is reducing retained austenite, there are several studies that claim that wear resistance is increased more dramatically after long-term cryo treatment from carbide precipitation. The same studies usually state that toughness is decreased after using long-term cryo as well.
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Do you have links to these studies, or addresses to write to to get copies?
 
Bors said:
Pulled this from the other post.

Is it that it did not work or that it just did not work for their application?

How many centuries did it take us to understand heat teating. Yes we new that if you heated steel to a certian temp and then quenched it it got very hard and if you heated it at a lower temp you tempered it which made it not so brittle. But could we "explain" what happened and why.......no.

It sounds like we are at the same stage as the early makers of centuries ago. That is we know something is happening but since we don't understand it we can't scientifically explain it.
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It is amazing to me that even though cryo has been around for so long, that no reliable comparative testing has been done.

PatriotDan said:
Would it not be relatively easy to prove cryo effect by testing identical blades - ones with cryo and ones without. See what happens to retention and toughness and so on. I actually think that knife manufacturers have done this. If there was an improvement with cryo why aren't all manufacturers using it? If not, why are some manufacturers using it?
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you would think, but if this has been done, then no one is posting the results or the results may be to inconsistent to form opinions.


here are some pics taken from www.300below.com

steelprocessing.jpg
steelprocessing.jpg


the article below indicates "fine carbides and resultant tight lattices are precipitated from cryogenic treatment"
http://www.300below.com/press/magazine-articles/swat--december-1995.html

another one of their articles that hints at what cryo does near the end:
http://www.300below.com/press/magazine-articles/shotgun-sports--january-1998.html

again more talk of refinement and a study done in Romania
http://www.300below.com/press/magazine-articles/short-track--october-1994.html

more
http://www.300below.com/press/magazine-articles/pumps--systems--april-2006.html


and here are all their articles:

http://www.300below.com/press/magazine-articles.html


here is an interesting article that was mentioned before I think:
http://www.airproducts.com/NR/rdonl...019GLB.pdf#search="cryogenic quenching steel"


here is a test graph taking from the following link:
http://www.metalscience.com/techinfo_ASM.php
wear_resistance_graph2.jpg


of course all this info is from sources that sell this service so how believable is it?
 
Have the above articles been peer reviewed? As far as I am concerned, scientific results need to be verified by peer review.
 
Keith Montgomery said:
Have the above articles been peer reviewed? As far as I am concerned, scientific results need to be verified by peer review.
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no clue, and I doubt it. However one of the links has several articles from many industries, but again no real test data for comparison, unfortunately.
 
Unfortunately these aren't links to the articles themselves.

* A Study of the Effects of Cryogenic Treatment on Tool Steel Properties; Barron, Dr. Randall F.; LA Tech University; LA Tech University
* A Study of the Effects of Cryogenic Treatment on Tool Steels.; Mulhern, C. R.; Louisiana Tech University; M. S. Thesis, 1973
* An Investigation into the Influence of Cryogenic Treatment on the Wear Resistance if Tool Steels; Smith, K. M.; Lanchester (England) Polytechnic; BS degree presentation, May, 1979
* Applications & Developments in the Cryogenic Processing of Materials; Kollmer, Kristoffer P.; Central Washington University; Mechanical Engineering Technology, Central Washington University, Technology Interface / Winter 99
* Below zero chilling toughens metals, increases tool life; Morris, V.; ; Machine and Tool Blue Book, Jan, 1955 pages 124 to 125
* Big Chill to Extend Gear Life; Brown, Joe; ; Power Transmission Design, September, 1995, pp 59-61
* Bringing Cryogenics in from the Cold; Koepler, Chris; Modern Machine Shop; Modern Machine Shop, March, 2001, pages 63,63
* Can I Benefit from the Use of Low Temperature Treatment; Bayer, H. E.; ; Steel Processing, Oct, 1953, Pages 502 to 508
* Cold Cuts; Paulin, Pete; ; Cutting Tool Engineering, Vol 44, Number 5, August, 1992
* Cold Facts on Stabilization; Kamody, Dennis; ; Metallurgia, January 2001, pp23-24
;

{ MUCH DELETED }
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http://www.cryogenicsociety.org/publications/cold_facts/current/cryogenic_processing_articles.php
 
Cryo has been shown to my satisfaction to be of benefit in a blade. My hangup is that "cryo-treated" means little or nothing to me unless the specifics are shown: Soak, sequence, temperature, retemper, etc. :)Regards, ss.
 
Please forgive me in advance for this drive by post.

All over my head, however I would like to add that the treatment would contract the steel to it's tightest highest density. A density that it has never been at and then it would have to expand again. I'm sure that this process would leave the steel in a different state than it was in before treatement.
 
mete said:
That MetalScience is BS. I didn't go beyond the first
quote . Metals have Metallic bonds not molecular bonds ,there are no molecules in metals only atoms crystals and grains !!! ...As for grain refinement lets take 52100 as an example .As we quench we first hit the Ms temperature [480 F ] where martensite starts to form. At 235 F we hit the Mf temperature which completes the transition to martensite .Therefore at that temperature martensite grains are completely formed and cannot be changed ,refined or otherwise !!! In practice the reaction is never complete .There will always be some retained austenite, the amount depending on alloy and heat treating variables. Reducing the temperature further will reduce but not completely transform that RA. The lower you cool it the less RA you will have....Sorry Cobalt but those are the facts though I've seen lots of BS especially from companies that sell cryo !
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I quoted Mete from the other thread so as not to go off topic there.

The one fact everyone agrees on is that it significantly reduces retained austenite.

All the other facts or claims, I should say, have not been independantly proven, or have they. If not, this is amazing to me that in so many years there is still no solid information on this process.
 
Once upon a time, stainless steel knives came in two flavors, brittle and soft. No respectable outdoor knives were made of SS. I have pre-WWII SS knives made by Victoria ("Victoria Inox"). Damn hard. No flex. Tried correcting a bend in one. Two pieces.

A company called Robeson, based IIRC on some German observations, developed a process of cryogenic treatment of SS ("Frozen Heat"). The result was SS knives with hardness and respectable toughness.

Where did I first hear this story? Don't recall. I'll look around. Robeson is, of course, gone -- with so many other U.S. makers.
 
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