Cryogenic "Chamber"

The difference between the hardness quenching cycle and thermal shocking the hardened blades during tempering has got to be obvious?

If you're looking for heat treating equipement, start checking out companies than make it. You're talking about a lot of money though. Tens of thousands of $. It only works out if you're ... wait for it ... heat treating parts all the time and making money with the machines.

That's why it's best to either go to the university and study the science or get a job with a company that can train you or just find a good heat treater that has the the equipment and the people who know what they're doing.

As one guy here has already pointed out, nitrogen can be very hazardous in untrained hands. But then a lot of things folks on these forums talk about doing out in ther garages makes me cringe.

If you want info on Elmax, call Uddeholm, they make the stuff!
 
Maybe you should re-read my first post.

This is a learning process, you know, the same way everyone learns to make knives..

If you look at the HT protocol from the maker it mentions a "sub-zero quench" there is not much information on how to do this on a small scale so thus I ask the question. We are looking at ovens and have grinders (KMG and a TW-90) so fine tuning the small details of knifemaking is the goal here.

I don't need a degree in metallurgy or a job at at heat treating company, I don't see all the other knife makers here doing that so why should I?

My question pertains to the cryo temper phase of PM steels and getting the most out of a heat treatment so performance is maximized, it would be helpful if you had some positive input on this subject.
 
Knifenut , a bit of mis information there.You might check my old posts on the subject.Briefly there are two different processes, "sub-zero quench " [ about -100F], . and "cryogenic quench"[300F ]' . The significant difference is that the cryo forms "eta" carbides while sub-zero doesn't . The most complex alloys will benefit from cryo while the lower alloy types won't.
 
Maybe I shouldn't have read it in the first place? Or wasted my time trying to answer it?

Guess what they offer at universities and in companies where people already know what they're doing: It's called "learning."

What you want is somebody to come along and solve all your problems for you. It dont work that way. You want to learn about about heat treatimg highly alloyed stainless steel in an afternoon on an internet knife forum. It's too complicated for that.

The answer you got didnt suit you. Too bad.

There are a lot of people dipping blades in nitrogen and selling it as "cryo treating." Like Garrison Keillor once said, "Sleeping in the garage doesnt make you a mechanic." The people buying those knives dont know anything about it. But then, if the knives break or fail in use, it may not be the end of the world either.

In the real world of heat treating where clients come from the auto and aircraft industry that is not cryo treating. Like I told, you need an expensive machine for that. You need more expierence and training than you can get on the internet or else you need a long and expensive process of trial and error. Reinventing the wheel they call that.

Or else you can buy a bottle of nitrogen on ebay and have at it.

I have all of my blades heat treated and cryo treated as needed by a company who do that everyday using millions of dollars in machines. So when I tell customers the blades were cryo treated, that means they were done according to industrial norms used in industrial production.

So now go do whatever you like.
 
Each to there own. But maybe you should check out some of the people like METE's credentials. Some others that have been on this forum and others have extensive knowledge of HT processed. Plus, one does not need a college to learn. If one wants to make the effort as some have you can learn on your own. I have bought books, read and studied them, paid attention when people like Mete and Kevin Cashen and others depart their considerable knowledge. I am sure some of the things that go on in my shop would probably cause you to soil yourself. But, Having spent much of my life working and managing work in several extremely hazardous industries, I believe that with knowledge, the proper respect, equipment and caution I can preform the process safety management to preform these things safely. I do my own HT and currently use a dry ice slurry, but, plan to move to a dewar and nitrogen. I believe and my test equipment and testing seems to confirm that I am doing a good job at this point, I believe I can improve. I am not too worried about the "thermal shock" of rapidly changing the steels temp 300+ degrees from ambient to that of liquid nitrogen than I am of rapidly quenching from 1850 to ambient. I am sure I have much more knowledge of the HT process than someone I used to know well who ran a shift at the place that HT huge quantities of different items, some of them pieces and blades for some well known companies, at a industrial HT company. Yes, they had some very nice equipment all of it ran by low paid workers and supervision that made little more, they just followed instructions. I got to tour the place and meet many who worked there on several occasions. Did they produce a better finished HT than I do? I highly doubt it, they just produced way more. There aree some interesting and critical things that must happen during a HT process. That does not mean that the "layman" can not preform the well with less than state of the art equipment.

PS, I have worked and supervised jobs where we have brought in liquid nitrogen in multiple tanker loads and flooded large piping systems of heat treated alloy piping and vessels with nitrogen. Thermal shock was never a big concern, control of the process and exposure to the hazard where. We often put men inside vessels that are held in a nitrogen atmosphere (or worse toxic atmospheres) to work. I have witnessed and worked with companies that HT large quantities of piping and piping welds used for hazardous and extreme industrial use. Their equipment and processes weren't all that special and the men at the sight were mostly only following HT recipes they were given.
 
Last edited:
Lets all try to stay civil and just address the question at hand.

Is professional cryogenic treatment the best way to do cryo - absolutely.
Is it the way to go if you have a large volume commercial knife manufacturing setup - absolutely.
Can cryo be done in a lower volume shop with a Dewar of LN - absolutely.
Can sub-zero treatment be done by hobbyists with dry ice and acetone - absolutely.
Does it take a good bit of reading and a moderate understanding of metallurgy to do these procedures - absolutely!
Will all of the above improve the quality of a high alloy knife - absolutely.
 
After working with asbestos, mold and lead, countless safety training classes and certifications, some time at a steel mill, and my father being in the fire service for 35 years with 10 years as the lead of a hazardous materials team plus writing what is now the standard decon procedures that you find in the OSHA manual I think I have a fairly good grasp on safety. And if not I can easily have a safety protocol written for me.

Now to get back on subject,

I am not asking how to cryo temper (I will figure that out in due time) I want to know with what tools other makers are doing it with. Is the tempering chamber I linked in my first post the only way to do it? I doubt that's the case... So what non-hackjob way do you cryo temper?
 
knifenut1013 said:
After working with asbestos, mold and lead, countless safety training classes and certifications, some time at a steel mill, and my father being in the fire service for 35 years with 10 years as the lead of a hazardous materials team plus writing what is now the standard decon procedures that you find in the OSHA manual I think I have a fairly good grasp on safety. And if not I can easily have a safety protocol written for me.

Now to get back on subject,

I am not asking how to cryo temper (I will figure that out in due time) I want to know with what tools other makers are doing it with. Is the tempering chamber I linked in my first post the only way to do it? I doubt that's the case... So what non-hackjob way do you cryo temper?
Click to expand...

Have you contacted the company and gotten a quote on that unit ?
I suspect the $ of that unit could suprise you
 
knifenut1013 said:
After working with asbestos, mold and lead, countless safety training classes and certifications, some time at a steel mill, and my father being in the fire service for 35 years with 10 years as the lead of a hazardous materials team plus writing what is now the standard decon procedures that you find in the OSHA manual I think I have a fairly good grasp on safety. And if not I can easily have a safety protocol written for me.

Now to get back on subject,

I am not asking how to cryo temper (I will figure that out in due time) I want to know with what tools other makers are doing it with. Is the tempering chamber I linked in my first post the only way to do it? I doubt that's the case... So what non-hackjob way do you cryo temper?
Click to expand...

Yeah but asbestos, lead and especially mold are all harmless anyway :)

I've ordered some temp logging gear so I can run a test out on burying the workpiece in salt. I'm convinced it is a good way to moderate the drop the in temp and to give it enough thermal mass to allow for a gradual return to ambient. There is no reason this should need major equipment to do well.

-Sandow
 
Sandow said:
The mist above LN is significantly warmer that the LN. It is steam relative to water.
Click to expand...
Actually, the manufacturers of the storage dewars say that with the foam neck plug in and the temp stabilized, the average temp in the LN is around -196C and the temp at the top of the flask at the neck is typically around -190C. Not so much difference between the liquid and the "steam" ;)
 
I have waited for some of the guys who do a lot of their own cryo to speak up. I now send all my cryo blades to Peter's, but used to do my own.

From what I have experienced and know of others who do their own cryo, the common practice is to suspend the blade in the tank neck for a while ( in the vapor area), then lower the blade in slowly...over several seconds, and then let it stay submerged for an hour or two.

I don't remember anyone saying they had any bad problems with this method. Would a controlled Cryogenic Chamber and a HPLN system be cool? (bad pun) - sure, but for that kind of money, you could probably outfit a shop with a top of the line power hammer and a press. I bet they aren't cheap to operate, either.
 
I am no cryo expert, but suspending the blade in the vapor at -190 would super cool the blade quite a bit slower than submersion in the liquid at -196 because vapor doesn't transfer heat nearly as fast as liquid.
 
You must log in or register to reply here.
Back
Top