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View Full Version : Cyrogenic tempering?



sergeant69
11-26-2010, 05:30 PM
i know this might sound sacriligious to you guys that make ur own baldes but i'm not to that point yet so buy mine. one place advertises an option on their stainless steel blades called CYROGENIC TEMPERING that they take down to -305F and they say it makes the blades keep their edges sharper longer. this true? thanks

EdCaffreyMS
11-26-2010, 07:19 PM
We commonly refer to this as "cryo". It's basic function is to convert retained austinite in the steel to martensite. This will result in a blade gaining 1-2 points of Rc hardness during the process, which requires an additional tempering cycle afterward. In my experience it can make the difference between a "junk" blade and an outstanding blade, particularly concerning certain types of stainless steels.
More often than not with most stainless steels, cyro will improve the overall performance and edge retention.

sergeant69
11-26-2010, 07:25 PM
and that answers that. THANKS. is good to know!

James Terrio
11-26-2010, 09:24 PM
Cryo, as I understrand it, is part of the quenching process that helps ensure full transformation of retained austenite to tough, hard martensite; then tempering is still needed as Ed pointed out.

The benefits of cryo really come into play with "stainless" steels that have a lot of alloying elements like chromium, nickel, molybdenum etc. Cryo can boost mediocre steels like 420C or AUS8 into very good performance, and helps excellent steels like CPM154 and D2 achieve their full potential.

Cryo doesn't seem to have as great an effect on simpler alloys like O1, 1095 or 1080 etc. I doubt it hurts anything but probably doesn't add much, either.

sergeant69
11-27-2010, 08:41 AM
you lost me after the first set of numbers, but as long as it enhances what i am currently buying (stainless) thats great. thanks