cryogenic temper

S

skinner

Joined
Oct 10, 2000
Messages
9
How many are doing a cryogenic temper on their blades? Have you noticed an improvement over just a regular tempered blade?
 
I freeze treat all my stainless and most of the straight carbon steels. I think it is a must for stainless. I bought a dewer off ebay and have it filled with liquid nitrogen when I get enough ground out to heat-treat. It brings the steels to full hardness and stress relieves also.
 
There is a specific manner in which you have to work the process though correct? You must have it down to one temprature, raise it up and the bring it back to normal, correct?
You can't just drop it in, wait a little bit, and then, presto facto, stronger exacto, can you?

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R/
William
 
There is alot of contraversy on this subject. With stainless steels, I remove the blade from the foil pouch, cool quickly with air from a fan, straighten if needed, (it amazes me that they can be straighted so easily at this time) when room temp and straight I dip them slowly in liquid nitrogen, leave them in for 6 hours and remove, then warm to room temp and temper twice. I use the rockwell tester at the college machine shop for final test. There may be other suggestions, but this is the way I have been told. Bruce
 
Bruce,

What temp do you bring it to the first time? Is there a specific temperature for each steel or is getting in the ballpark good enough?

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Peter Atwood

email:fountainman@hotmail.com
 
The temps are all critical to acheive consistant hardnesses. Each steel has its own suggested set of instructions which include temps and times. I collect data like this when I see it and print it up. Paul Bos is the man that I call on if Im confused with too many variations on one steel. He makes it seem so easy. He has heat-treated for 30 years. Tell me what steel you are doing and I can give the info I have. Bruce
 
Thanks for the info Bruce. I'm going to be using ATS34 for some folder blades. I thought I would probably send them out to be heat treated, maybe to Texas Knifemaker's Supply. I'd like to have them cryo quenched as well. I'm not afraid to do it myself and I'd like to learn more about these techniques but I'm really just at the beginning so I have a whole lot to learn.

BTW, what does heat treating generally do to Ti as far as hardness goes? I have played around a lot with scrap that I have and it seems to me that after heat coloring, the material is a lot harder and stiffer. Is this just my imagination?

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Peter Atwood

email:fountainman@hotmail.com
 
Peter, I use to send my blades to Paul Bos. He is very good. Texas Knifemakers is good too though. I have never played with heat-treating Ti. Tell me what you find out. My next big purchase is a rockwell tester. That would help you with your Ti experiments. Bruce
 
What do they charge for filling a 30 liter dewar where u are???
They hit me for almost $70 here!!!!
Harry Jensen
 
I pay $22.oo for 6 liters. In cold weather like this it lasts for about 2 weeks. It lasts longer if I prefreeze the blades first in the wifes freezer. Bruce
 
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