cpm3v has the same edge retention of 440c??????

[ukknifer]

http://www.burgessknives.com/media/Crucible$20Knife$20Steels.pdf

(Please see page 2)
I saw this graph that says basically that cpm3v has the same edge retention of 440c and that 3v has less edge retention than 154c. That was a surprise to me. I thought 3v was a super steel (whatever that means). The graph also shows A2 to have very low edge retention , about half that of 440c. I thought A2 was much better than 440c.

Am I missing something?

 

[jossta]

Check out this chart:

3v is a super steel b/c of it's toughness, not it's edge retention. But based on this it is still better than 440c in wear resistance. Depends on the heat treat too.

 

[kalama]

my opinion is,,3v is better not by the charts but my personal test i have done ,,i am no expert ,but in my test, the 3v knives i have did better than my D2,A2,52-100,an 3G steel knives i own,,this pass weekend i was able to field dress,butcher,an debone five hogs,plus carve ,batton,make fire sticks ect.. with out sharpening them or doing touch ups during the process..

 

[neuron]

First, I don't know where they're getting their info, but 3V's wear resistance (which I assume is what they mean by "edge retention") is around 25-30% better than 440C's -- see the chart jossta posted above. Second, what makes 3V special isn't its wear resistance per se, but rather the fact that it offers 154CM/S30V-level wear resistance in combination with crazy high toughness -- again see the chart.

Third and most importantly, different steels have different combinations of properties that make them good for different applications, so unless you're comparing an all-around crappy steel (e.g., AUS-4) to an all-around excellent steel (e.g., M390), it doesn't really make sense to say some steel is "better" than one another without qualifying with some sort of answer to the question "better for what?" In the case of A2, it has very good toughness and is easy to sharpen, which makes it a good choice for larger fixed blades and the sorts of applications/conditions they're likely to be used in. By contrast, 440C would generally be better for a folding knife where toughness isn't at such a premium and corrosion resistance is likely to be more important.

 

[jdm61]

The new 4V is supposed to have 20% more impact resistance than A2, which is a much lower than 3V but still good because A2 is among the best of the "normal" air hardening steels as far as toughness goes. But the 4V is also supposed to have 3 times the abrasion resistance of 3V and like 6 times that of A2.

 

[neuron]

The new 4V is supposed to have 20% more impact resistance than A2, which is a much lower than 3V but still good because A2 is among the best of the "normal" air hardening steels as far as toughness goes. But the 4V is also supposed to have 3 times the abrasion resistance of 3V and like 6 times that of A2.

Pretty sure 4V's increase in wear resistance over 3V is more on the order of 30% (i.e., 1.3 times) rather than 3 times. If 4V had 3 times the wear resistance of 3V, that would put its wear resistance around that of S90V, 9V, and other 9% Vanadium steels, which isn't very plausible given 4V's alloy content and attainable hardness.

 

[jossta]

Everyone talks about 4v, but 9v seems like it's where it's at. For everyone except the person that has to grind it, of course.

 

[Tim616]

Why the hell are we comparing a SS to a CS.

 

[EricV]

Wish that chart had s60V /440V on it. Very handy chart just the same though, thanks for posting!

 

[jdm61]

You are correct. 30% or so better than 3V and 3 times that of A2. The interesting thing about 4V is that, although we are obviously talking about lower absolute numbers, the impact resistance doesn't seem to drop off as rapidly as 3V does a it gets harder.

Pretty sure 4V's increase in wear resistance over 3V is more on the order of 30% (i.e., 1.3 times) rather than 3 times. If 4V had 3 times the wear resistance of 3V, that would put its wear resistance around that of S90V, 9V, and other 9% Vanadium steels, which isn't very plausible given 4V's alloy content and attainable hardness.

 

[scouter27]

Why the hell are we comparing a SS to a CS.

I think people tend to get too wrapped around the differences. Really they're all mostly iron, so why not compare them?

 

[neuron]

You are correct. 30% or so better than 3V and 3 times that of A2. The interesting thing about 4V is that, although we are obviously talking about lower absolute numbers, the impact resistance doesn't seem to drop off as rapidly as 3V does a it gets harder.

I hadn't looked into that aspect of it before, but you're right that it is a very cool/interesting property of 4V as compared to 3V. Seems like, especially for folders and smaller fixed blades, running 4V at a high hardness could offer a nice bump in wear resistance while still leaving it with more than enough toughness for anything one might use a folder or small fixed blade for. :thumbup:

Everyone talks about 4v, but 9v seems like it's where it's at. For everyone except the person that has to grind it, of course.

I've often wondered about 9V myself. At least on paper, it seems to offer an awesome combination of very high wear resistance and high toughness, yet I've never seen a knife made out of it even in the custom world (although I'm sure a few have). Steels like 10V, S90V, and S110V, which have comparable wear resistance (and are comparably difficult to grind), are still used in custom knives and occasional production knife runs, so my guess is that a lack of attainable hardness is what's keeping 9V from use as a knife steel. It'd only designed to be hardened to the mid-50s HRC, and that lower hardness is a big reason that it has such a big jump in toughness compared to to 10V (which is almost always at 60+ HRC). For some industrial tooling applications, a hardness of around 55 HRC would probably work, but for something as thin as a knife edge, it seems like a recipe for significant edge rolling.

 

[jossta]

I think Peter R is going to try a fixed in 9v, so well see what happens. Could be wrong though.

 

[neuron]

I think Peter R is going to try a fixed in 9v, so well see what happens. Could be wrong though.

Definitely looking forward to seeing how it performs. Like I said above, the hardenability/edge stability thing is just speculation (on the basis of the info in the data sheets) about why we see almost no use of 9V in the knife world. It'd be nice to have some actual knives in 9V out there to help answer the question, since materials can sometimes over- or under-perform in particular applications in ways one wouldn't predict on the basis of their composition and industry-standard tests (e.g., the charpy impact test for toughness).

 

[Joshua J.]

http://www.burgessknives.com/media/Crucible$20Knife$20Steels.pdf
(Please see page 2)
I saw this graph that says basically that cpm3v has the same edge retention of 440c and that 3v has less edge retention than 154c. That was a surprise to me. I thought 3v was a super steel (whatever that means). The graph also shows A2 to have very low edge retention , about half that of 440c. I thought A2 was much better than 440c.

Am I missing something?

In other tests it's better than S30V, "edge retention" is very task specific, and no-one truly understands it quite yet.

Everyone talks about 4v, but 9v seems like it's where it's at. For everyone except the person that has to grind it, of course.

Edit: What he said.

I've often wondered about 9V myself. At least on paper, it seems to offer an awesome combination of very high wear resistance and high toughness, yet I've never seen a knife made out of it even in the custom world (although I'm sure a few have). Steels like 10V, S90V, and S110V, which have comparable wear resistance (and are comparably difficult to grind), are still used in custom knives and occasional production knife runs, so my guess is that a lack of attainable hardness is what's keeping 9V from use as a knife steel. It'd only designed to be hardened to the mid-50s HRC, and that lower hardness is a big reason that it has such a big jump in toughness compared to to 10V (which is almost always at 60+ HRC). For some industrial tooling applications, a hardness of around 55 HRC would probably work, but for something as thin as a knife edge, it seems like a recipe for significant edge rolling.

 

[puukkoman]

These minor differences and the magnitude with which they're debated and rehashed are funny. Humans did all their cutting with sharp stone flakes for tens of thousands of years, and now people who don't do more in a day than punch a keyboard and cut a pickle in half at lunch time are concerned with the "edge retention" and "toughness" of their steel knife blades. Heh.


And yes, I'm a hunter and woodsbum and actually use my knives, before anyone starts slinging mud. Regular old carbon steel, like 1095 or 1080, works just fine for me. Even stainless, like Buck's 420HC, performs well enough in my hands to make me wonder what everyone could possibly be doing with their knives that could make them need "better edge retention" than these lowly, joe-sixpack steels. Maybe there's a species of large mammal with sand paper for skin, and muriatic acid for blood? I don't think so...

 

[jossta]

Human nature to want better, even if you don't need it. Who the hell needs a 650hp twin turbo V12 mercedes? All about pushing the envelope.

 

[jdm61]

The other interesting question will be if 4V reacts positively to the much lower tempering temperatures (in the 400F range for 3V, IIRC) and cryo like 3V does. The only specs they have on that chart are the "standard" stuff in the 1000F range.

I hadn't looked into that aspect of it before, but you're right that it is a very cool/interesting property of 4V as compared to 3V. Seems like, especially for folders and smaller fixed blades, running 4V at a high hardness could offer a nice bump in wear resistance while still leaving it with more than enough toughness for anything one might use a folder or small fixed blade for. :thumbup:

I've often wondered about 9V myself. At least on paper, it seems to offer an awesome combination of very high wear resistance and high toughness, yet I've never seen a knife made out of it even in the custom world (although I'm sure a few have). Steels like 10V, S90V, and S110V, which have comparable wear resistance (and are comparably difficult to grind), are still used in custom knives and occasional production knife runs, so my guess is that a lack of attainable hardness is what's keeping 9V from use as a knife steel. It'd only designed to be hardened to the mid-50s HRC, and that lower hardness is a big reason that it has such a big jump in toughness compared to to 10V (which is almost always at 60+ HRC). For some industrial tooling applications, a hardness of around 55 HRC would probably work, but for something as thin as a knife edge, it seems like a recipe for significant edge rolling.