CPM-10V Steel - History, Properties, and How to Heat Treat

Very interesting, thanks for sharing Larrin!

Side note - got your book and it’s fantastic. The HT index in the back is great as well. With regards to tempering, does your recipe always assume 2, 2hr cycles at listed temp? Couldn’t find that listed.

Thanks as always for the incredible info!
 
I haven’t used much 10v so far, but I do like it. I will be using more in future.

Great article on the development and heat treat. This is one of the steels that really benefits from a refined process.
 
pmbspyder said:
Very interesting, thanks for sharing Larrin!

Side note - got your book and it’s fantastic. The HT index in the back is great as well. With regards to tempering, does your recipe always assume 2, 2hr cycles at listed temp? Couldn’t find that listed.

Thanks as always for the incredible info!
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2x 2 hours is fine for 99% of steels given a low temperature temper. Some of the high tempering temperature (1000-1050°F) steels may benefit from a 3rd.
 
Good stuff!

I have a lot of 10v profiled that I have yet to heat treat because I'm not too sure about order of operations.

I am making framelock and friction folder blades, I usually grind them 100% post heat treat... should I pre-grind the 3v to near finished state prior to heat treat? I like to grind with high speed and pressure if that matters.

I'm not too concerned with finish, I'll probably just stay with a 120-220 grit ceramic belt at the most.
 
Daniel Fairly Knives said:
Good stuff!

I have a lot of 10v profiled that I have yet to heat treat because I'm not too sure about order of operations.

I am making framelock and friction folder blades, I usually grind them 100% post heat treat... should I pre-grind the 3v to near finished state prior to heat treat? I like to grind with high speed and pressure if that matters.

I'm not too concerned with finish, I'll probably just stay with a 120-220 grit ceramic belt at the most.
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You will glaze belts quickly if you grind at high speed with high vanadium steels. I grind post heat treat. Going finer than 120 doesn’t get you much. I find structured abrasives do better at higher grits than regular ceramics.
 
Larrin Larrin I have purchased ok folders like Spyderco and Benchmade to try steels like S110V and have found that while they don't ever get dull they don't stay super sharp for very long. I have heard others with the same issue. Is this a sharpening issue or HT or is it to be expected with these types of steels?
 
Storm W said:
Larrin Larrin I have purchased ok folders like Spyderco and Benchmade to try steels like S110V and have found that while they don't ever get dull they don't stay super sharp for very long. I have heard others with the same issue. Is this a sharpening issue or HT or is it to be expected with these types of steels?
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It’s a pretty common claim with “super steels” that they lose initial sharpness quickly but then hold a reasonably sharp edge for a long time. I am not sure if this behavior is actually “real” however, for a few reasons.
1) initial sharpness is highly variable and minor burrs can have a big effect on initial edge retention.
2) loss of initial sharpness happens pretty quickly and even having high wear resistance can only push that out so much. Between points one and two the “noise” can overwhelm differences.
3) our biases about “super steels” can color our perception in use.
4) there doesn’t seem to be a consistent pattern to these claims. Some will say they see it in a low carbide steel while not seeing it in a high carbide steel which would be backwards from what I expect if it is “real.” There is no microstructure or property (hardness, toughness, etc) that points in a single direction.
5) in CATRA testing the high wear resistance steels do better on cut number 2 onwards (or cycle number one using the conventional CATRA method of combining a forward and backward stroke into a single “cycle”). There is more scatter in early cuts but when averaging it all out the high wear resistance steels do better from the beginning.
 
There are some definite sharpening issues involved that have to be ruled out.

Abrasives are a huge part of this.

You'll need diamond/CBN to shape the apex and cut all the carbides to shape inside the apex.

Using ceramic abrasive will only wear the steel matrix surrounding the carbides. It will break and tear the carbides to shape rather than cut them to fit neatly in the apex.

So folks are leaving some performance on the table when using ceramic abrasives on steels like this but ceramic abrasive inherently polishes best.


Also, the problem is folks think all diamond stones are created equal, the electroplated diamond stones have abrasive grains that are proud of the surface and will create a deep scratch that is not conducive to a push cutting hair shaving edge.

The bonded stones such as resin, vitrified and metallic diamond/cbn will create a better surface finish since the abrasive grains are embedded in a bond like the ceramic abrasive waterstones do.

So I feel the sharpening has to be ruled out before saying universal that these steels don't hold the front end sharpeness, I feel only when they are shaped with ceramic.


Here is a knife in rex121 at 70.5 hrc, only bonded diamond /CBN was used and diamond loaded strops.
Under 50g BESS is supposedly a sub micron apex according to the BESS folks

8ZuAvcZ.jpg





Storm W said:
Larrin Larrin I have purchased ok folders like Spyderco and Benchmade to try steels like S110V and have found that while they don't ever get dull they don't stay super sharp for very long. I have heard others with the same issue. Is this a sharpening issue or HT or is it to be expected with these types of steels?
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I think the other issue is geometry. Most production knives are too thick. Thick just doesn’t hold an edge as well as thin.
 
Larrin said:
It’s a pretty common claim with “super steels” that they lose initial sharpness quickly but then hold a reasonably sharp edge for a long time. I am not sure if this behavior is actually “real” however, for a few reasons.
1) initial sharpness is highly variable and minor burrs can have a big effect on initial edge retention.
2) loss of initial sharpness happens pretty quickly and even having high wear resistance can only push that out so much. Between points one and two the “noise” can overwhelm differences.
3) our biases about “super steels” can color our perception in use.
4) there doesn’t seem to be a consistent pattern to these claims. Some will say they see it in a low carbide steel while not seeing it in a high carbide steel which would be backwards from what I expect if it is “real.” There is no microstructure or property (hardness, toughness, etc) that points in a single direction.
5) in CATRA testing the high wear resistance steels do better on cut number 2 onwards (or cycle number one using the conventional CATRA method of combining a forward and backward stroke into a single “cycle”). There is more scatter in early cuts but when averaging it all out the high wear resistance steels do better from the beginning.
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Is it perhaps that most of them are not as hard as some other "super" steels? I will admit to being part of the club that likes steels in the Z-Wear to M4 range but most of my experience with them has been in the 64Rc range compared to 59 to 61 Rc. I think that I understand that edge stability is mostly based on kinda a sliding scale of task, hardness and toughness but the ultra high carbide steels feel like they play with some different rules. Don't think that i am arguing this i just feel like I'm missing something when I try to understand the concept of how all this works. For example if once you get to a high enough carbide content do you need to change sharpening technique or abrasive? I assume that abrasives act finer when used on harder materials would that be enough to give a different experience for the user? Every knife that I really thought performed better than most all had tungsten additions. Could that make sharpening easier by reducing toughness?

If this is all in your book just tell to go buy your book. Lol.
 
Storm W said:
Don't think that i am arguing this i just feel like I'm missing something when I try to understand the concept of how all this works.
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Things definitely get very difficult to understand when we are describing phenomena that don't actually occur. I am certain that some steels can lose sharpness at different rates than others, but I do not find compelling some of the arguments about what steels those are. Higher hardness and higher wear resistance leads to better edge retention. In cases where the edge is blunting by chipping or rolling the behavior will be more dominated by other mechanisms (toughness or hardness respectively).
 
Willie71 said:
You will glaze belts quickly if you grind at high speed with high vanadium steels. I grind post heat treat. Going finer than 120 doesn’t get you much. I find structured abrasives do better at higher grits than regular ceramics.
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That my friend is simply not true .Ceramic belts are probably a waste of money on some grinders that have neither the speed nor power and the belts will glaze and go blunt very quickly.........words of wisdom !
 
Natlek said:
That my friend is simply not true .Ceramic belts are probably a waste of money on some grinders that have neither the speed nor power and the belts will glaze and go blunt very quickly.........words of wisdom !
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Its best not to speak in absolute terms. He is not talking about the first part of removing material. Trying to grind a thin chef's blade down to a zero edge does not allow the use of much pressure and glazes belts. A full flood system would help but it would still be hard to grind something that thin at high pressure. Every full time knife maker that uses those type of steel that i have heard of burns through a lot of belts. They have all the power and speed that they need and would love to spend less but have to do things a special way to maintain their quality. The whole thing makes sense if you remember the the higher carbide is for wear resistance.
 
Storm W said:
Its best not to speak in absolute terms. He is not talking about the first part of removing material. Trying to grind a thin chef's blade down to a zero edge does not allow the use of much pressure and glazes belts. A full flood system would help but it would still be hard to grind something that thin at high pressure. Every full time knife maker that uses those type of steel that i have heard of burns through a lot of belts. They have all the power and speed that they need and would love to spend less but have to do things a special way to maintain their quality. The whole thing makes sense if you remember the the higher carbide is for wear resistance.
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If you can t use much pressure there was belts with less grain on given surface just for that ,to use them with lower pressure .Glazing come from not apply enough pressure on them not from fast speed of belts .Fast speed is recommended from every manufacturer of belt and my personal experience confirmed that .Faster better .....and pressure , lot of pressure. And belts last !
That was reason why I use jig for grinding bevels .Jig allows me to apply right pressure which with hand is almost impossible to do , especially on thin blade .
One more thing , I apply same pressure from start to end even that is thin blade almost to zero edge and never over heated single on .I found that high pressure and high speed /over 6000FPS/ generate less heat .If pressure is too low causes the abrasive to rub, rather than cut and that friction incurred from the rubbing increases the heat between the belt and the steel . This can result in pieces of the steel to being welded to the grain of belt ..............
Sorry for of topic !
 
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Natlek said:
That my friend is simply not true .Ceramic belts are probably a waste of money on some grinders that have neither the speed nor power and the belts will glaze and go blunt very quickly.........words of wisdom !
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I have played with speed and pressure. I can get 5 or more blades out of a belt with low speed and medium to high pressure.

The recommendation for high pressure and speed comes from industrial applications, which have automated processes that human hands can’t match. I can feel the difference between a belt cutting, and glazing.

You do things your way. I’ll do them mine. I used a zirconia belt while waiting for a belt order to grind two z-max knives, and two k390 knives, all above Rc66. At high speed, I wouldn’t have been able to grind one of those blades with a zirconia belt.
 
For people starting with these steels, remember what you are making is important. The larger the surface area of the knife you are grinding, the more likely the belt will glaze rather than cut. The finer the grit, the more likely the belt will glaze not cut. Pay attention to the feedback in your hands. Try freehand grinding and concentrate on how hard the belt is pulling the blade down.

Different people use different pressure. This is why we disagree on which belt is best. The abrasives have different friability ratings, meaning they fracture off and leave a fresh grit at different pressures. Learn your needs, speeds, and pressures. Each Smith has favourites, but in general we agree on the basics.

As an analogy, try skipping a small pebble across a lake. It doesn’t matter how much speed or spin, it sinks pretty easily. Now try a disc shaped rock, it has to slow down before it breaks the surface. Same principle here. The larger the surface area, the slower you have to go to cut in, or you have to massively increase pressure. We all know that we use slower speeds as grit goes up. Finer grit has a harder time biting into the steel. Same thing happened with higher carbide size or volume. The grit has a harder time digging in to pull out the carbides. Slow down. Try it for yourself. Kim Nolan was
over a couple months back, and I showed him the speed I was using on a Z-max, R69 knife. It was a worn belt too. It just cut right in and left a stream of filings, rather than throwing sparks. The little blade was 1/2 ground in four passes.


If you hollow grind you will have a different experience with pressure and speed than a full flat grind. If you make mostly edc or pukko knives, you will use different speeds and pressures than kitchen knives.
 
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