Cryo for free ?

P.K.Hansen

P.K.Hansen

Joined
Aug 8, 1999
Messages
402
A friend has offered me free cryo-treatment of my blades. This would happen after the blades are returned to me after heattreating and tempering. Can it still be done at this time or must it happen sometime during the heattreating proces ?
 
It's not a service I'll be able to provide to anybody - sorry.
This friend of mine works in a factory that uses cryo to test their products, and he will have to sneek the blades in when the boss is not around ;)
I just need to know if it is worth the trouble or not.
 
My understanding is that it needs to be done after the first temper cycle. Following the cryo the blade MUST be tempered again and perhaps even for a third time.
 
From everything I've read, and from my own limited experience with the dry ice cold quench, it's worth it. I've had a few blades cryoed professionally too but no reports on how they perform. But the immense difference the dry ice quench makes suggests liquid nitrogen would be super. :cool:

Give it a shot and if you get to do some testing, please let us know your results.

Dave
 
I'm with Dave. The last one I did with a full cryo made all the difference. It was like someone else made the blade:D IMHO it needs to be done either after the quench or after a short temper. This depends on the steel. We had a very good thread on this a while back. Do a search and it should turn up.
 
Initial development work on the technique was carried out over 30 years ago and they worked with material that had been heat treated weeks or months before and still saw a significant improvement. Back then they did not temper after cryo as the material had already been tempered.

Current practice is to HT, cryo, and temper.
 
P.K.: You can cryo your blades after multiple tempers and they will improve. You will get the best result if you temper 2x after the cryo. If the tempering temp for the steel is above your capability, you should temper at 300F for 2 hours at least once.

Folks-remember-- You have tempered Martensite and retained Austenite prior to cryo. The cryo is converting the retained Austenite to un-tempered Martensite. This is why you need to temper the fresh Martensite produced by the cryo treatment.

RJ Martin
 
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