Talk to me about no cryo heat treat.

I think you misunderstood my answer. This is what I was answering:
"I was unaware that RA can convert to martensite under certain conditions. That is very interesting. Converting as much RA as possible via cryo treatment would reduce the chance for late stage martensite embrittlement then?"

My answer was to that question, not the value of cryo.

I never said cryo or DI has no real-world benefit? It is highly encouraged, and I would never sell a knife that required it without doing cryo/DI.
Before anyone else jumps in saying cryo and DI are not the same, I am lumping both processes as cold treatments. There are differences, but both reach the Mf.
 
Cypress Creek Knives said:
Stacy, if the use of cryo doesn't have a "real world impact" (meaning it doesn't make a noticeable difference to the average user doing average tasks), why is there such an emphasis on this step? I understand that as makers we want to get the most performance out of our steel (I do use a cryo step and plan on continuing to do so), but is it really necessary? It seems to me that "good enough" comes into play here. All of these extra steps add cost and time to a blade, and at some point the benefit added won't exceed the cost and time increase. If this is the case, and the average user won't notice any difference, why are we so hyper focused on it? Does skipping cryo make a knife inferior to one that has been cryo treated, or are we just catering to the few who are steel snobs, like many of us here?



I agree with you and Lorien that edge geometry plays a larger impact on performance than a cold step or not. I feel like there is appropriate focus on the edge geometry discussion, and perhaps too much focus on cold treatments. The discussion around cold treatments tends to suggest that a non cryo treated blade is an inferior product than a cryo treated knife. I'm not convinced that this is the case, hence my post on the subject. As a maker and user I'm more interested the real world difference. If I can make a non cryo blade with great performance and save my customers a chunk of change on each knife, it may be something to consider.
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Even with doing dry ice my cost for cold treatment is less than $1 per blade as long as I’m running a batch of 20-30 and usually I’m heat treating more than that. And that’s for a one shot use, LN is even cheaper when you spread it out over multiple batches in a 3-5 month window. I’d have to get a wide mouth dewar and those don’t hold for nearly as long as the standard dewar and cost more upfront which is why I’m still using dry ice. So at the end of the day it doesn’t really cost my customer more for the cold treat.
 
Stacy E. Apelt - Bladesmith Stacy E. Apelt - Bladesmith I understand that there are benefits to a cryo/DI treatment and that it is encouraged, but is it as important as everyone makes it seem? I know that there are hundreds, if not thousands, of knives out there that did not undergo a cryo treatment (when it would be beneficial, not speaking of low alloy steels). What I am trying to understand is, are those knives actually inferior ( I know a lot of this is likely anecdotal and subjective) to a cryo treated knife. It seems to me that everyone is saying how important cryo is, but I haven't seen quantitative data to support that.

For example, MagnaCut can achieve a hardness of 62 with cryo/low temp temper, no cryo/low temp temper, and no cryo/high temp temper. What is the advantage of the cryo step? I realize more RA will be converted using cryo or a high temp temper, but is that really as important as it is made out to be?
I don't disagree that cryo is important, but I'm not sure that I find it as important as everyone is saying, at least from a users standpoint.
 
Cypress Creek Knives said:
Stacy E. Apelt - Bladesmith Stacy E. Apelt - Bladesmith I understand that there are benefits to a cryo/DI treatment and that it is encouraged, but is it as important as everyone makes it seem? I know that there are hundreds, if not thousands, of knives out there that did not undergo a cryo treatment (when it would be beneficial, not speaking of low alloy steels). What I am trying to understand is, are those knives actually inferior ( I know a lot of this is likely anecdotal and subjective) to a cryo treated knife. It seems to me that everyone is saying how important cryo is, but I haven't seen quantitative data to support that.

For example, MagnaCut can achieve a hardness of 62 with cryo/low temp temper, no cryo/low temp temper, and no cryo/high temp temper. What is the advantage of the cryo step? I realize more RA will be converted using cryo or a high temp temper, but is that really as important as it is made out to be?
I don't disagree that cryo is important, but I'm not sure that I find it as important as everyone is saying, at least from a users standpoint.
Click to expand...
Then test it
 
Lorien said:
one thing that sucks about using LN2, for me, is that it somewhat limits what I can make/design- for the reason Josh mentioned. Not only is the opening of my dewar about 2", the whole tube that protrudes into the vessel is the same diameter, so really wide knives won't fit and wideish knives with a curvy profile won't fit. I'll get a bigger dewar one of these days, but space constraints are a real issue for me currently
Click to expand...

One can use a styro cooler or plain metal pan for that matter to cryo a blade that won't fit in the Dewar. Put cooler on floor, pour some LN2 in it CAREFULLY, then put the knife in. All it needs to do is get down to temp and stabilize. Conversion is rapid. I used a fish-cooking long pan and would just let it evaporate
 
The problem with heat treating is that you can’t see it. Design, materials, workmanship is all on display.

Because you can’t see it, it doesn’t matter how terrible a HT you can get away with.

They will bring up alloy and hrc and conveniently omit some of the important steps.

Good heat treating doesn’t always feel productive.

The more testing we do the more important I believe it is.

Hoss
 
to summarize - Larrin claims that cryo is NOT necessary for a decent heat treat - simple as that !
 
I have followed this thread with interest, not having access to cryo facilities make me wonder if it is any use at all trying to make a knife from stainless steel?
Here are some of my random un-scientific rambling thoughts.
I am sure that 95% or more of the worlds stainless steel knives have not received the benefit of cryogenic treatment. In the real world of tool steel, where costs of production downtime and retooling can be enormous dents to the bottom line, it is clearly an advantage to relax the FCC structure and precipitate out the fine carbides to increase hardness and reduce the adhesive wear characteristics of a particular tool steel, and any improvement in certain properties, no matter how small, can lead to massive reduction in the previously mentioned costs and enhance profitability. This is the factor that has driven research in cold treatment of tool steel, not knives. We are tagging along trying to see what benefits there are for us, if any, and as the OP asks, is there a real world benefit to most knife users? We should be thankful that certain individuals are taking their expertise and time to focus on knife application of cryogenically and conventionally heat treated tool steels.
The general feeling I am left with, being new to knifemaking, is that we must reduce retained austenite as it weakens the steel, but in many examples in "Knife steel nerds" toughness is reduced after cryo and RA is almost zero, why is that? Surely the precipitation of fine carbides at the grain boundaries is a good thing, it seems to me that here we have, as in most things knife making, a compromise to be made. Sure enough more carbides in the steel leads to harder steel, but also means that the steel is vulnerable to easier crack initiation and faster crack propagation which is probably the reason for the reduced toughness. Fine carbides, precipitated due to cryo treatment, at the edge should mean that any given steel " gets sharper" than the same steel not so treated, and increased resistance to adhesive wear, and smaller carbides should mean you will need better stones but it will be easier to remove the wire edge on sharpening. I do not think that anyone would be able to discern between a particular steel that is cryo or not cryo treated unless they are incredibly familiar with that particular steel, in use, and have the wherewithal to measure those differences, but I maybe underestimating knife folks.
 
Way-Barney said:
I have followed this thread with interest, not having access to cryo facilities make me wonder if it is any use at all trying to make a knife from stainless steel?
Here are some of my random un-scientific rambling thoughts.
I am sure that 95% or more of the worlds stainless steel knives have not received the benefit of cryogenic treatment. In the real world of tool steel, where costs of production downtime and retooling can be enormous dents to the bottom line, it is clearly an advantage to relax the FCC structure and precipitate out the fine carbides to increase hardness and reduce the adhesive wear characteristics of a particular tool steel, and any improvement in certain properties, no matter how small, can lead to massive reduction in the previously mentioned costs and enhance profitability. This is the factor that has driven research in cold treatment of tool steel, not knives. We are tagging along trying to see what benefits there are for us, if any, and as the OP asks, is there a real world benefit to most knife users? We should be thankful that certain individuals are taking their expertise and time to focus on knife application of cryogenically and conventionally heat treated tool steels.
The general feeling I am left with, being new to knifemaking, is that we must reduce retained austenite as it weakens the steel, but in many examples in "Knife steel nerds" toughness is reduced after cryo and RA is almost zero, why is that? Surely the precipitation of fine carbides at the grain boundaries is a good thing, it seems to me that here we have, as in most things knife making, a compromise to be made. Sure enough more carbides in the steel leads to harder steel, but also means that the steel is vulnerable to easier crack initiation and faster crack propagation which is probably the reason for the reduced toughness. Fine carbides, precipitated due to cryo treatment, at the edge should mean that any given steel " gets sharper" than the same steel not so treated, and increased resistance to adhesive wear, and smaller carbides should mean you will need better stones but it will be easier to remove the wire edge on sharpening. I do not think that anyone would be able to discern between a particular steel that is cryo or not cryo treated unless they are incredibly familiar with that particular steel, in use, and have the wherewithal to measure those differences, but I maybe underestimating knife folks.
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Granted I am familiar with the steels but when I went from no cryo and high temper to cryo and low temper I was surprised at how well my Cruwear and 3v knives started performing not only in edge stability but also corrosion resistance.

I ran coupons with 14C28N and feel ok running the steel with no cryo and only a cold treatment in the freezer but I have to drop down in austenetizing temperture and thus hardness. I would not sell these knives in my current market as nobody wants 14C28N at 59 Rc but they would make a usable knife.
 
victoroni said:
to summarize - Larrin claims that cryo is NOT necessary for a decent heat treat - simple as that !
Click to expand...
You can get a knife with decent HT from Ikea for 15 USD.
You can get a knife with good to very good HT for 30-100 USD from a knife store.
Custom knives with the price point exceeding the above should in my opinion include excellent to superb HT.
 
FredyCro said:
You can get a knife with decent HT from Ikea for 15 USD.
You can get a knife with good to very good HT for 30-100 USD from a knife store.
Custom knives with the price point exceeding the above should in my opinion include excellent to superb HT.
Click to expand...
You took the words out of my mouth. I have to drive an hour plus one way to the nearest Airgas facility, spend roughly $38 to get my 10L dewar filled. The LN2 lasts me about a month so I plan to get all my heat treating done in that time frame. Enough to keep me busy for a couple months anyway. I never once made the excuse that it was too much of a hassle or thought that it wasn't worth it to add cryo into my heat treating process. I never once read an article or comment that stated or said cryo was bad for the process. There again, I never once looked at one of my knives and said "good enough". People a lot smarter than me have determined with irrefutable evidence that cryo does infact increase performance and at worst does nothing at all. I want to be amongst the best so I'll take my chances with the occasional road trip and 2 cases of beer and a couple Slim Jim's worth of LN2.
 
DevinT said:
I think I'm going to write a book entitled “The cheap lazy bastard’s guide to heat treating”.

Hoss
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I smell a best seller in the works!
 
My comments were regarding statements I often hear from knifemakers: "Steel X doesn't need a cryo treatment so I use it for my knives." "Steel Y has to have a cryo treatment or it has poor performance." No steel needs cryo, and no steel has the same performance without cryo. If you are not using cryo you have to modify the austenitizing temperature lower to ensure there isn't excess retained austenite. And with cryo you can adjust the austenitizing temperature higher to achieve higher hardness. But in general I recommend cryogenic processing for lower retained austenite, better resistance to edge deformation, and higher wear resistance.
 
i guess ill offer my head to the "Chopping Block"
Guys that say it is "Good Enough" why are you making knives ?? if you are willing to compromise on the quality of knife you are going to build....
yes a Dewar and Nitrogen aint cheap/free... but if it makes the blade/"Heart" of the knife better, just follow the free advise of the guys spending lots of time/money to share
with your lazy butt the secrets they found.. or not !!!!! maybe those that say they know better should do Their Own Research !!! oh yea that would require Effort on their part!!!!!
some people..
 
Seedy Lot said:
Granted I am familiar with the steels but when I went from no cryo and high temper to cryo and low temper I was surprised at how well my Cruwear and 3v knives started performing not only in edge stability but also corrosion resistance.

I ran coupons with 14C28N and feel ok running the steel with no cryo and only a cold treatment in the freezer but I have to drop down in austenetizing temperture and thus hardness. I would not sell these knives in my current market as nobody wants 14C28N at 59 Rc but they would make a usable knife.
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Were the 3V and Cruwear knives you tested the same hardness? As in no cryo vs cryo? Or were you running the cryo blades at a higher rc?
FredyCro said:
You can get a knife with decent HT from Ikea for 15 USD.
You can get a knife with good to very good HT for 30-100 USD from a knife store.
Custom knives with the price point exceeding the above should in my opinion include excellent to superb HT.
Click to expand...
I agree that custom knives should have a superb HT. My question is, is cryo definitively better. It seems that I hear a lot of "it's better because it's better" statements and it isnt substantiated. From the studies and writings on the subject, it doesn't seem like there is any real conclusive evidence. Certainly not enough to call a non cryo treated blade inferior. In many cases cryo will make a knife reach a higher hardness, but also make it less tough.. that isn't necessarily a good thing.

Again, I pose the question: If I want to heat treat a magnacut knife to 62rc. Why is the cryo method superior?
The answer I receive is along the lines of "because cryo makes the blade harder" I dont find that to be an answer at all. Why does a higher as quenched hardness matter if I'm still tempering down to 62rc? It also seems to me that removing RA and introducing finer carbides at the edge (via cryo) can also result in a blade that is prone to cracking (or faster crack propagation). Again, I dont think this is necessarily a good thing.

As W Way-Barney said above, a lot of things in knife making involve compromise, and the more I learn, the more I am inclined to agree with him.

Maybe I just take issue with the statement that cryo treatment makes a better blade when it isn't definitively true. I think it does a disservice to makers who don't use a cryo step for whatever, often well informed, reasons.
 
Pinoy Knife said:
i guess ill offer my head to the "Chopping Block"
Guys that say it is "Good Enough" why are you making knives ?? if you are willing to compromise on the quality of knife you are going to build....
yes a Dewar and Nitrogen aint cheap/free... but if it makes the blade/"Heart" of the knife better, just follow the free advise of the guys spending lots of time/money to share
with your lazy butt the secrets they found.. or not !!!!! maybe those that say they know better should do Their Own Research !!! oh yea that would require Effort on their part!!!!!
some people..
Click to expand...
Every maker faces the "good enough" question. I think it is safe to assume that every maker says there are imperfections in their work, yet they still sold it. That means the knife was "good enough". Also, cost/benefit comes into play as well. Could I make a "perfect" knife. I'm sure I could reach that level of satisfaction in my work, but the time, effort, energy, and mess ups along the way would result in me losing money on the sale. So I am left with the decision of "when is good enough, good enough"

I'm not saying all the knowledge and testing that these great people have done is wrong or incorrect. I'm personally not convinced that it is as important as everybody says it is. That is why the question was asked in the first place. Larrin has done wonders for the knife community and great strides have been made because of his work. I just haven't seen enough empirical evidence to convince me that cryo is as important as the community believes. I use cryo steps in my HT process and intend on continuing to do so.
 
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