Is CRYO treatment the new edge packing

[Willie71]

The purpose of learning about steel and heat treating is not to overcomplicate, add extra steps, or chase infinitesimally small improvements. Instead it is to understand which parameters are the most important, how to optimize heat treatments, and to understand the mechanisms at work so when someone says, "you can't make a good knife without cryo" you know what elements of that statement are true and which are not. To make things simple sometimes you have to understand many aspects that may appear unimportant. If knifemakers wanted to follow heat treatment recipes there would perhaps be less to understand. But as long as we have people asking, "Why can't I just heat treat with my torch?" or "Does XXXX steel need cryo?" or "Should I be triple quenching my steel?" there is more education required to answer those questions. So there is a balance between knifemakers who are frustrated by over-information and say, "Just tell me what to do," and all of those "creative" knifemakers trying to do things that don't make sense, or chasing optimizations that make no perceptible difference because of misunderstanding of how things work. I fall on the side of more information is better, though in the end the decision-making is not that complicated. It takes more information to be able to make simple decisions.

I agree 100%. I stopped doing four tempers and do two, or three depending on other variables. I do one hour in cryo, not overnight or 24h now. I no longer do the pre heats. My process is simplified, but the important parts remain.

 

[Mr.Wizard]

One very practical reason to use cryo is that the burr formed during sharpening is much easier to remove with cryo than without.

Can cryogenic treatment help with this specific aspect years after a blade has been made, or does it have to be done at the time of manufacture?

 

[DeadboxHero]

Can cryogenic treatment help with this specific aspect years after a blade has been made, or does it have to be done at the time of manufacture?

Time of manufacturer. Out of curiosity, I tested a cheap 8cr13MoV knife. No change in hardness before and after.
Also different ranges of austenitizing temps will have more or less effect on boosting hardness in combination with cryo after quench.

No idea what the 8cr13mov was austenitized at but whatever retained austenite is in there it's not going anywhere.

It is still stubborn to deburr.

I recommend reading Larrin's cryo article again.

 

[DevinT]

Can cryogenic treatment help with this specific aspect years after a blade has been made, or does it have to be done at the time of manufacture?

Most RA stabilizes within a few hours and is finished stabilizing within a couple of days. There are times where certain high speed steels will benefit from cryo some if they were tempered at the higher temperatures even after some time has elapsed.

Hoss

 

[JTknives]

Most RA stabilizes within a few hours and is finished stabilizing within a couple of days. There are times where certain high speed steels will benefit from cryo some if they were tempered at the higher temperatures even after some time has elapsed.

Hoss

I watched a YouTube guy do a test with HSS drills in a cnc machine. He had a handful of the same drills and half where cryo treated in his shop. Thy where marked by someone else so he did not know which was which. The cryo treated drills vastly outperform the non. Was interesting to watch but made me wonder how thy where heat treated at the factory.

 

[Hubert S.]

I watched a YouTube guy do a test with HSS drills in a cnc machine. He had a handful of the same drills and half where cryo treated in his shop. Thy where marked by someone else so he did not know which was which. The cryo treated drills vastly outperform the non. Was interesting to watch but made me wonder how thy where heat treated at the factory.

I remember watching the video below a few months ago, might be the same one. I like the youtube channel, he does all kinds of neat experiments.

 

[SBuzek]

For me cryo is the most economic way to reach Mf. Had my dewar for 12 plus years and can get LN 15 minutes from my house for 1.10 liter. Usually lasts about 2 months.

 

[Storm W]

One very practical reason to use cryo is that the burr formed during sharpening is much easier to remove with cryo than without.

Most knife makers don’t know how to sharpen, and most knife users are even worse.

Hoss

Hey just a sidebar. I have made a couple of knives out of A2 and 3V. Both had a LN quench. They are miserable to debur and it seems like the burr keeps coming back. Any ideas about what I did wrong.

Sorry to sidetrack but it is semi relevant.

 

[DevinT]

Hey just a sidebar. I have made a couple of knives out of A2 and 3V. Both had a LN quench. They are miserable to debur and it seems like the burr keeps coming back. Any ideas about what I did wrong.

Sorry to sidetrack but it is semi relevant.

How hard are they?

Hoss

 

[Storm W]

How hard are they?

Hoss

I don't know the hardness. I don't have a tester. I have misplaced my heat treat notes in a move but I was trying to run them near the top of the recommended HT data. I was pretty surprised with the A2 since I should have ended up around 64 Rc if I recall correctly. They were plate quenched with no snap temper. And should have been in the LN in less than 10 minutes.

 

[DevinT]

I don't know the hardness. I don't have a tester. I have misplaced my heat treat notes in a move but I was trying to run them near the top of the recommended HT data. I was pretty surprised with the A2 since I should have ended up around 64 Rc if I recall correctly. They were plate quenched with no snap temper. And should have been in the LN in less than 10 minutes.

How did you sharpen them?

Hoss

 

[Storm W]

How did you sharpen them?

Hoss

DMT bench stones. Sometimes some light strokes on a spyderco medium ceramic bench stone. I am a fan of course edge sharpening and usually use a course or medium diamond stone but I have tried all the grits down to extra fine diamonds. I have cut corks ran the edge through end grain soft wood and tried light strokes at a increased angle on a finer stone to debur. I use a paint stir stick loaded with diamond paste to strop. This has been a winning combo on pretty much every other knife I have sharpened. The only time I have ran into burrs like these is on cheap soft knives.

 

[DevinT]

DMT bench stones. Sometimes some light strokes on a spyderco medium ceramic bench stone. I am a fan of course edge sharpening and usually use a course or medium diamond stone but I have tried all the grits down to extra fine diamonds. I have cut corks ran the edge through end grain soft wood and tried light strokes at a increased angle on a finer stone to debur. I use a paint stir stick loaded with diamond paste to strop. This has been a winning combo on pretty much every other knife I have sharpened. The only time I have ran into burrs like these is on cheap soft knives.

Not sure then, I’ve made lots of knives out of A2 and a couple of dozen knives from 3V and never had a problem with stubborn burrs.

Hoss

 

[Storm W]

Not sure then, I’ve made lots of knives out of A2 and a couple of dozen knives from 3V and never had a problem with stubborn burrs.

Hoss

I probably screwed up the heat treat somehow. Or my oven is off although everything else has come out great. Thanks for taking the time to troubleshoot.