DEEP CRYOGENIC TEMPERING (-305F) vs CRYO TEMPERING

I appreciate your input fellas...I'll keep working at it 'til I get it right! Just looking for the answers that will increase my performance levels.

Thanks Again!
shane
 
First - carbon steels contain only carbon as a major alloying element.1084, 1095 are carbon steels. 5160 and 52100 are alloy steels.1084,1095and 5160 would not be expected to have retained austenite therefore would not benefit from cryo. The more complex the alloy the more it MIGHT benefit. Much of cryo is hype unfortunately. BAINITE - this is formed when the steel is quenched to ABOVE the Ms temperature and held a long period until it's complete.It is tougher than martensite and good for impact , swords or survival knives. MARQUENCHING - produces martensite but minimizes stress of the quench ,used mostly for complex shaped parts. Retained austenite is found in alloys where the Mf temperature is below room temperature. The cryo temperature really need only to drop below the Mf of the steel. That will transform retained austenite to UNtempered martensite which then MUST be tempered.
 
First - carbon steels contain only carbon as a major alloying element.1084, 1095 are carbon steels. 5160 and 52100 are alloy steels.1084,1095and 5160 would not be expected to have retained austenite therefore would not benefit from cryo. The more complex the alloy the more it MIGHT benefit. Much of cryo is hype unfortunately.
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Amen.
 
Hi there. New to your forum...I was asked to place my head square on your chopping block. Found it a novel concept, so thought I'd oblige.

If I can answer any questions, we'd be happy to give it a whirl.

We used about 18 million cubic feet of nitrogen last year processing a little over 4 million various types of blades. (last year) Ring me up if you like. 800-550-2796

We've started 162 independant deep cryogenic processing operations worldwide. We've been at cryo a while, since Ed Busch originated the commercial cryogenic processing industry as our founder almost forty years ago in 1966. We have been "flattered" as they say, many times. We were originally known as Permo-Bond then Material Enhancement Hazel Park MI, then Cryo-Tech and now 300 Below Inc. of Decatur IL.

We funded the industry research performed by Dr. Randall Barron at Louisiana Tech. Our Chairman Emeritus and Founder is Ed Busch with 68 years in the heat treating industry. John Koucky is our Vice President with a degree in Metallurgy from the University of Illinois and an MBA from Northwestern. He was the Vice President of Technology for Wagner Castings, one of the largest Q1 foundries in the US.

I guess that still makes us the largest, oldest and founders all at once. That and $2.50 will get you a cup of coffee, but my thought is that we have had a fair amount of experience along the way.

It is how I make a living anyway. You do seem to have a few colorful characters, as I peruse some inflammatory statements. I don't care to argue or match wits. I've even run into five people at shows who've told us that they started 300 Below Inc. in the business. (They didn't even know they were talking to me at the time.) It's still a Wild West out there.

I'll share what I can, to the best of our ability. We are not here to seek your business. In fact if you call me , I'd be happy to process custom blades for you for free.

We have processed over 20 million blades, and anytime you do something 20 million times, you get pretty good at it.

Warm Regards,

Pete Paulin
CEO
300 Below Inc.
2999 Parkway Drive
Decatur IL 62526
300below.com
 
What a great offer Pete! Thanks.

The forum has everybody on it. All experience levels and traditions. But you know in the year I've been here no big wars have broken out.

I'll probably send you some blades myself. I'm very new to heattreating and am trying/testing every procedure I can - limited by funds and equipment.

I'm looking forward to hearing more from you.

Steve

BTW do you care to input on the "liquid nitro vs. dry ice/acetone on complex alloys" debate? I'd like to know.

PS, "Warm Regards" is a pretty funny closing from a company called 300 Below Inc.
 
Good post Pete. Please stop by here at 'Shop Talk' often. Lots of us, myself recently included, cryo their blades - some shallow and some deep. I may bother you with a call sometime with specific questions but will hope instead you can lend yourself here from time to time with a post or two as you see the subject come up. Cryo is a popular subject here at times.

Roger
 
I have to agree with Ed Fowler's comments above. I use 52100 on about 75% of my knives. Paul Bos does my cryo after I do the initial hardening/tempering. I used to notice a significant increase in strength after the cryo, but more recent tests I cannot tell a difference between cryo and non-cryo with 52100 blades. I will continue to do it just in case until I am convinced that there is no change.

As to the edge flex tests, I assume that what's happening is that you're not getting full conversion of austenite into martensite during your quench. That leaves the blade a little less hard and therefore slightly more flexible without the cryo. When you cryo you are completing the martensite conversion and the blades are gettting harder and need a higher temper. I have to temper my 52100 blades at 400 degrees for a RC of 60, so at 425 you're around 59 RC which is plenty good if everything else is there.
 
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