Cryogenics questions

P

panama red

Joined
Aug 11, 2008
Messages
18
I just came across some cryogenic equipment that could be adapted to blade treating, and I have a lot of questions. Does anyone here use cryogenics in their treatment processes? Is -350 degrees cold enough? At what stage in the process is cryo used? Could I get my blades heat treated elsewhere and put them through the cryo myself, or is there a time window between the processes that must be adhered to? After I get my paid membership, I will probably put some of the cryo equipment on here for sale.

Sorry for so many questions. I'm new here, and new to knifemaking.

Thanks,
Dave
 
I use cryo when heat treating stainless blades (153CM). High alloy steels see the most benefit from cryo treatment. Cryo is used in high alloy steels to transform retained austenite to martensite, which usually isn't a problem in carbon steels like 1095 etc. Yes -350 is plenty cold enough to do the job, generally anything close to -100 and colder will work fine. Some guys cryo after a snap temper, fearing a cracked blade. I prefer to do it right after the quench and haven't cracked a blade yet. As soon as the blade reaches room temp it is ready to go into the dewar where I usually let it sit for a few hours. When you remove the blade from the dewar, let it come back to room temperature then temper the blade.

All that being said, cryo treatment of blades isn't precisely defined recipe that everyone adheres to. If you ask 10 makers that use cryo, you will probably get at least 8 different answers as to how they do it. In the end it all comes down to testing the blades that you make to be sure they are up to snuff.

Edited to add:
I missed that you were new to knife making in your first post. Working with high alloy steels that benefit from cryo is an expensive place to start out your blade making journey. High alloy steels require precise heat treating procedures in a controlled oven $$. I recommend you get your feet wet on carbon steels and work your way up if you find you like making blades. If you really want to start off with high alloy steels, I suggest you send the first bunch that you make out for heat treating.

Welcome to Bladeforums.

Brad,
www.AndersonKnives.ca
 
Last edited:
Dave,
I have put just about everything imaginable into my dewar. That being said, I have found it to be beneficial to improving the stainless steels I have tested. I have also found it to seem to be beneficial to improving the performance of certain carbon steels. In particular, 52100 and 5160. I have not been able to get any benefit from the basic steels like 1095, 1084, 1080.
According to the folks at Crucible Steel, the cryo step should always follow a full temper cycle. This is of course is to cover their liability issues. I know a lot of people who got straight to cryo from heat treat. Before You do that, I would suggest that you start by using the steps set out by the steel manufacturer. Especially since you are new to knifemaking.
I too, like Teknition, would suggest that you start out with a simple forgiving steel for a while. Something like 5160 is very simple to heat treat, benefits from cryo, nice to grind, and most of all, relatively inexpensive to obtain. Then you can afford to play with it and learn first hand what it is capable of.
I still use 5160 for a lot of my knives. That is the steel I chose to build my ABS JS performance knife from. And yes, I did cryo it!!!

Good Luck,

Steve
 
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