Cryo treating

Bronco

Bronco

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I was perusing Jerry's website and couldn't find any reference to whether or not INFI blades are cryogenically treated. I also did a search here and didn't turn up anything either.

As cryo treating is generally something worth advertising for those who do it, I'll assume that this isn't a normal part of the Busse manufacturing process. I'm curious to know if this is something Jerry has ever considered doing, and if any benefits could be realized by subjecting INFI blades to this process. I've never heard of a steel that didn't benefit from cryo freezing, but I'm certainly no expert.

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Semper Fi

-Bill
 
All Busse Knives, in every product line, are cryogenically quenched, and have been for years. In fact, Busse Combat was one of the first shops to integrate it as a standard process in their heat treating and tempering recipe...of over 80 hours collectively.



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Andy Prisco, Manager
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Thanks Andy,
Great info. Why am I not surprised
smile.gif
. Since I believe that most people view cryo treating as a plus, Jerry might want to modify the copy in his website and advertise this fact.

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Semper Fi

-Bill
 
Are the blades forged, done by stock removal, or some combination thereof?

How are they sharpened? I know my Battle Mistress came very sharp, as did my Bussee Combat Hatchet, but my Steel Heart II and Badger Attack did not come particularly sharp.
 
I just looked at that post on SF (really deep stuff). So if this is true why does Busse even bother with Cryo treatment? If there shouldn't be a need for cryo treatment if the heating process is done Correctly or optimaly then why do it. Andy or someone in the know... Does the properties of INFI cause it to resist completely converting to martinsite from austinsite in the heat treating process which warrants the use of cryo for complete conversion? Or is the cryo treatment the main thing that hardens INFI. If not and the cryo treatment doesn't help the steel conversion perhaps it is just to help them funtion better and stay sharp longer when under extreme heat conditions like say in a forest fire or such. If this is true then cryo treating for a Busse is just to prepare the blade for anything.

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Everything is negotiable!
http://albums.com/j/AlbumList?u=879893

[This message has been edited by Ryu (edited 07-02-2000).]
 
sorry--posted in error

[This message has been edited by WILL YORK (edited 07-02-2000).]
 
That article is very misleading. Any retained austenite will transform to martensite over time. This rate of this transformation will be enhanced by cold working so the edge will feel it first. It is critical to note that this transformation happens after the blade has been tempered so there will be nothing to remove the localized high stress regions that are created. Not a good thing.

A deep cryo should be done as part of the tempering process, it is of course not the last step. Besides allowing 100% transformation to martensite it also refines the grain structure and enhances the creation of very high wear resistant eta carbides.

-Cliff

[This message has been edited by Cliff Stamp (edited 07-03-2000).]
 
Cliff,
Exactly how many College degrees do you have and in what areas? I tell ya... I consider myself to be intellegent (no jokes needed here guys) but Cliff always seems to make me feel like a 4th grader. Though your point is well made. I now see the importance of the Cryo treatment. I wonder why someone would try to make you believe that a process that is so good for a blade is not needed. I mean no one would tell you that it's not good to exercise to keep health. Why down play Cryo when it is such a healthy thing for steel?

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Everything is negotiable!
http://albums.com/j/AlbumList?u=879893
 
Ryu :

Why down play Cryo when it is such a healthy thing for steel?
Click to expand...

Because it is more difficult to have a full cryo as part of the heat treat and as long as there is "contention" about its abilities, makers can ignore it and tell the customer it doesn't matter. Similarly, it is far more difficult to work with the high end steels so people say steel is not important and offer 1095 blades as direct alternatives to the Busse Combat INFI line.

I would assume that there were people working with Bronze who made similar arguments against Iron, and there were also people who believed it. That is of course until they had direct experience with iron vs bronze, and for the brief moment that they could reflect on their choice they probably realized there was something to the argument after all.

-Cliff
 
Boy! you're making quite a comparison there Cliff. INFI to modern steels is like Iron to Bronze... I like that. Perhaps we should call this the INFI age then. I would consider myself lucky if I was actually witnessing the new generation of steel craft. Imagine if one day because it is such an awesome material all knives were made from INFI and we considered the days when knives were made of A2 and crude materials like that to be old technology. Even the ones you buy at wal mart for your kitchen would be INFI. That would be cool.

------------------
Everything is negotiable!
http://albums.com/j/AlbumList?u=879893
 
Busse has been doing cryo since the early 1980's. Back then it was a very primitive process involving an old cooler, dry ice and about a gallon of acetone. Process: pack the blades in dry ice, pour the acetone over the ice to speed the evaporation process, and hit somewhere around the -190 degree mark. Do a normalizing temper (approx. 350 - 450) and voila! Prehistoric Cryo!

In the late eighties we began the employment of a deep cryo treatment (-300/320 degrees) which was done in a dry, controlled, atmosphere. This process allows us to take our blades down to temp. over the course of 10 hours hold them at temp. (-300 degrees) for approx 50 hours, and then bring them back up to room temp. over the course of the next 10 hours at which point they receive 3 more, individualized, oven tempers. This is the same process that we employ to this day.

Some makers are out there just plunging their blades into liquid nitrogen which can shock the steel so dramatically that microscopic cracks and fissures can form that could cause massive blade failure in the field under heavy and/or light use. That is why it is crucial that the blades be cooled slowly and brought back to room temperature slowly and then normalized with a few oven tempers for stress relief.

Of course there are also some makers that I know of who claim to employ cryogenics because they stick their knives in the freezer over night. Scary! Alway ask the maker to give as much detail of his cryo process as possible.

Knowledge is power! Arm yourself!

Yours in Nuclear Cryogenics,

Jerry Busse


 
OK! Well then. Now we know. From the man himself. I left my knife in the freezer all night once. It was by mistake. Didn't really do anything but make it really cold. I bet -300 would just turn your skin to dust if you were to grab one of those things fresh from the cooler. Thanks Jerry. I never had a doubt. If it goes into a Busse it must be needed. Otherwise Busse Knives wouldn't be the @#*&

------------------
Everything is negotiable!
http://albums.com/j/AlbumList?u=879893
 
austenite...martensite...eta carbides... ???

For those of us who lack the metallurgical expertise to know what Jerry, Cliff, and others are talking about, would someone kindly take a moment to expain, using small words, exactly what happens to INFI steel while it sits at -300F for 50 hours? I'd love to be able to better explain to my buds just how my Steel Heart II became the nuclear tough piece of bladeware that it is...

Thanks
 
When knives are being made the steel it is in a very soft and weak form because it is easy to machine. Once the bulk of the grinding has been completed you want to change the form of the steel to make it harder, stronger and more wear resistant.

Basically you heat it up until and then rapidly cool it back down. This changes the steel from the weak austenite to the very strong martensite (~68 RC). But this form is too brittle. So now you heat it up again, just a bit and cool it down, and make tempered martensite. Which is a bit softer, but far, far tougher.

What a deep cryo allows (mainly) is a full 100% tranformation to martensite in the middle step and thus eliminates all austenite (the soft weak stuff you don't want) from the steel.

Carbides are just really hard bits in the steel (like rocks in concrete). Deep cryo also enhances the formation of really wear resistant types.

-Cliff

[This message has been edited by Cliff Stamp (edited 07-05-2000).]
 
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