blkbear Posted August 9, 2007 Share Posted August 9, 2007 I have done several searches in different forums but cannot find any info on cryogenically treating blades. I have a number of questions that I hope someone here can clear up for me. I am in the process of making some blades from O1 and CPM3V steel. If I choose to use cryogenic treatment for them what exactly does the cryogenic process do? Does it harden and temper the blade? How many times should the blade soak for hardening and then tempering? Also - final edge sharpening. Before or after cryogenic treatment? I have found that when using heat to harden and then temper blade steel there is mixed opinions. Some like to sharpen before hardening and tempering and some prefer after the hardening and tempering process. Can I have your thoughts and opinions on this issue as well?? Thanks!! Brian Quote Link to comment Share on other sites More sharing options...
jeremy k Posted August 9, 2007 Share Posted August 9, 2007 Brian - interesting read - - http://swordforum.com/forge/cryogenics.html - this is just a link from a google search to start with - use at your will. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted August 9, 2007 Share Posted August 9, 2007 Cryogenics are generally used to change retained austenite to untempered martensite---remember to temper after the treatment as well as before! It is generally only good for alloys that have an appreciable ammount of retained austenite---usually high alloyed steels. As to it's effects there is a rather heated discussion on whether it's the greatest thing since high carbon steel or just a marketing ploy. Thomas Quote Link to comment Share on other sites More sharing options...
Rich Hale Posted August 9, 2007 Share Posted August 9, 2007 As for sharpening, I sharpen as the very last step in the process. after I have completed the knife and sheath and signed my name to the blade. When I sharpen it is ready to be sold. Before heat treat I only rough grind the blade. You should leave extra for the slight changes in shape. As for Hardening and tempering. Be safe. Follow the manufacturers recommendations. They made the steel, no one is better to refer to as to how it should be treated. The Stainless steels I use are heat treated followed by cryo treatment, according to the manufacturers specifications. Use your judgment. You will likely get so many opinions here that it will tend to lead you a lot of different directions. Have fun. Quote Link to comment Share on other sites More sharing options...
Quenchcrack Posted August 9, 2007 Share Posted August 9, 2007 Thomas covered it pretty well. High carbon, high alloy steels, like D2 will respond well as they tend to have a lot of retained austenite. There is a company called 300 Below that used to have a website with a lot of good technical information. It is common to Cryo tooling used in the metal working industry. The whole cryo thing is really just a continuation of the quenching process. You can do a poor mans cryo with dry ice but make sure you cool the blade slowly or you can crack it. Real cryo is done with liquid nitrogen. Since the transformation of austenite to martensite is dependant on only temperature once you clear the pearlite nose, rapid cooling is not necessary. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted August 10, 2007 Share Posted August 10, 2007 One thing to remember is that the "manufacturer's specs" are generally based on 1" cross section material; your 1/16" knife proto edge may act very differently. A lot of the top pros have very annotated copies of the manufacturer specs. For example a steel that is oil hardening may air harden on the thin sections and so forth. Quote Link to comment Share on other sites More sharing options...
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