Cryo testing

Hi Daniel,

interesting work. More statistics would be nice before drawing any definitive conclusions though. Seems you are probably going in that direction from your replies. What imaging techniques are you using to determine grain size?

Cryo treatment is a subject I have a great deal of interest in studying beyond the general knifemaking books surface treatment of the field. Can you recommend any specific articles from scientific journals that are the standards for reference purposes? Your apparent knowledge in this area indicates you have probably done the necessary background research to determine these. I'd appreciate any pointers that might save me some time at the library. I'm a physicist by training so don't worry that they might be too technical for me. All of my previous work has been in nuclear physics, chemical physics, and nanotechnology but I've not had the need to delve into the study of cryo techniques in great depth. Thanks for any pointer you can provide.

BTW, one of the things that I absolutely love about the knifemaking community is the openness and willingness to share information whether it be technical details or on how to improve our craftsmanship. On the other hand, it is standard fair in any field of scientific research to not talk about specific details until the papers are published in peer reviewed journals. Industry is another ballgame all together, in that techniques are generally kept as trade secrets, so I do understand your trepidation to not post all of the details of your process...although we all would love to hear about it. Having said that, independent verification from a reputable lab is going to be a necessary thing for you to pursue to publish results with confidence. It would remove any questions of bias in the experiments.

It's good to see some results being published of your testing. I look forward to reading more and appreciate any literature references you can provide.

All the best,
-Darren
 
Danial: I only do a snap temperon Tool Steel, Stainless is put in cryo. right after Quench. Cryo. has been around for many years, But there is still alot to learn about it. Keep on testing and good luck. Paul.
 
Paul,

Is a there a reason stainless does not need the snap temper first or would it be better to ask: why does tool steel but not stainless??

Thanks; Roger
 
Roger: Tool steel has a tendencey to crack if taken down that low after quench, So I do a 375 temper or stressrelieve befor i do the cryo. Some makers that do there own heat treating do it right from the quench, I cant take that chance with my customers blades. Paul.
 
Daniel, Thanks for that, but I was just being my typical sarcastic self.:D Sometimes it does not come across well in text....:footinmou

No offense was intended, hope you didnt take any. You have a cool thread going here. One day I might try using stainless, but right now I am stuck on C1095 and 15N20 damascus.

Got any HT processes for that?

I would love to hear em.
 
Paul
You're saying you cryo tool steel
is this to say all tool steels as to include O1 or just the ones
just short of being Stainless as in D2 air quenched ?

I think You know why I'm asking ..
 
Dan: I dont do Oil hardining or water hardining steels any more. I do cryo all air hardining steels, It dose toughin it up quite a bit. I know a lot of the guys that forge use Cryo also, some do it befor temper and some do it between tempers. Paul
 
Roger: Stainless should be cryoed after quench to make sure you get rid of all retained Austinite. Paul.
 
Paul,

Nice to have you participating in this thread. Please excuse my error as to your techniques.

I had never tried adding a snap temper before cryo until recently, after hearing about your use of it. It went against some of my theories. To my consternation I found that in a couple of cases I may have gotten a higher hardness with snap temper. I understand the need for it in some cases. However by doing a faster cool to -120F and very slow cool from there, I THINK that I may have eliminated the need for that. So far we have not had any cracking or loss of performance without snap.

We are currently running a series of experiments dealing with this question.

Daniel
 
Darren,

Some of the important academic papers on cryo treatment of steels are:

1. Dr. Randall F. Barron: "Cryogenic treatment of Tool Steels", Mechanical Engineering Department, Louisiana Tech University Ruston, Louisiana.

2. Dr. Randall F. Barron and C. R. Mullhern: "Cryogenic Treatment of AISI-T8 and C1045 Steels", Louisiana Tech University, Ruston Louisiana, Ford Bacon, and Davis Company, Monroe, Louisiana.

3. Fanju Meng, Kohsuke Tagashira and Hideaki Sohma: "Wear Resistance and Microstructure of Cryogenic Treated Fe-1.4Cr-1C Bearing Steel, Department of Mechanical Engineering, Muroran Institute of Technology.

4. Fanu Meng, Kohsuke Tagashira, Ryo Azuma and Hideake Sohma: "Role of Eta-carbide Precipitation in the Wear Resistance Improvements of Fe-12Cr-Mo-V-1.4C Tool Steel by Cryogenic Treatment", Muroran Institute of Technology, Department of Mechanical Engineering, Mizumoto, Muroran, Hokkaido, 050 Japan.

5. K. Moore and D.N, Collins: "Cryogenic Treatment of three Heat-Treated Toll Steels", Department of Mechanical Engineering, University College, Dublin Ireland.

There is also a paper done at Jassy Polytech in Romania that I have not yet located.


Some good links are:
http://www.cryoeng.com/images/Cold Cuts.htm
http://www.sub-zero-cryogenics.com/articles.html


Daniel
 
Darren,

Those judgements of grain size were done by naked eye. But it was a trained eye.

Daniel
 
Hi Daniel,

"Those judgements of grain size were done by naked eye. But it was a trained eye."

You knew I was going to respond with this right: That's a little suspect. Contact Len Landrum to see who he's using for microscopy in his studies of refining the heat treatment of 52100. You could turn this study of yours into some real definitive results if you follow through with proper protocol. Unfortunately, I don't have access to the Hitachi S-4700 HRSEM (high resolution scanning electron microscope) I used to use on a regular basis or I'd offer to run the samples up for you.

Good luck on your research, please do keep us all posted and please do seek someone to image your samples so you can quantify your results.

-Darren
 
Graymaker,

Tests at Louisiana Polytech showed a 418% increase in wear resistance of O-1 after cryo.

Daniel
 
That is interesting
The reading I've had on it said little or no improvement.
do you have any links to the data on those test?
I just may do a little more investigating. thanks Daniel..
 
Graymaker,

Here is a list of the percentages of wear resistance gained for various tool steels. The first number represents the gain by cold treatment (-110F), the second that by computer controlled deep cryo
(-310F).

AISI # Description of steel (-110 F) (-310 F)
D-2 High carbon/chromium die steel 316% 817%
A-2 Chromium cold work die steel 204% 560%
S-7 Silicon tool steel 241% 503%
52100 Bearing steel 195% 420%
O-1 Oil hardening cold work die steel 221% 418%
A-10 Graphite tool steel 230% 264%
M-1 Molybdenum high speed steel 145% 225%
H-13 Chromium/moly hot die steel 164% 209%
M-2 Tungsten/moly high speed steel 117% 203%
T-1 Tungsten high steel steel 141% 176%
P-20 Mold steel 123% 130%
440 Martensitic stainless 128% 121%
430 Ferritic stainless 116% 119%
303 Austenitic stainless 105% 110%
8620 Nickel-chromium-moly steel 112% 104%
C1020 Carbon steel 97% 98%
AQS Graphitic cast iron 96% 97%
A-6 Manganese air work cold die steel 73% 97%
T-2 Tungsten high speed steel 72% 92%

Source: Dr. R. F. Barron, Louisiana Tech University
 
Thanks Daniel
talk about shock...
I cryo'd two blades (154cm)today and took one blade
that is a photo type for my new folder line coming out
that is of O1,so while waiting for the SS blades to cool

I heat treated the folder blade,, this time not the way I
normally do it.
I hardened the Blade/ quenched in Oil ~ 125 deg. veggie oil
then put it in the LN2 before it was down to room temp.
kept it there until it stopped boiling,
took it right out warmed it until the frost melted.
drove it right into the pre heated oven at 425 deg.
for an hour.

now I know ....shock:eek: but thinking about it what more shock
to you get then by going from~1600 deg to~200 deg in about 15 sec.
well I'm testing shock you might say. she does pop the hair nicely.
I'll check cutting and the rest later..:)
by the way I checked with my gas guy on helium he won't get it for me it runs about 5 time as much as LN2 I still think
it's worth the money if I can get it.
 
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