Shootout: CPM-S90V vs CTS-20CP

[flatface77]

...I personally find I like M390 even more than S90V and similar steels except perhaps when cutting cardboard. It seems to take and keep a razor edge much longer than the other high vanadium steels, as well as S30V...
...I think I see the true appeal of M390. There isn't another stainless steel that really comes to mind when I think of one that takes and holds a razor edge like a carbon steel. Not as tough sure, but the edge it takes isn't lost with a mere few cuts...

This property is what has attracted me to this steel. The comments of Ankerson & others were the deciding factor in my pulling the trigger on my 1st M390 blade. When I read things like "takes a very fine edge" or "loses it's peak sharpness quickly before settling ..." ect, I perk up. The extra wear & stain resistance is just icing on the cake. These newer generation powder steels like M390 & Elmax somehow seem to be adding edge stability to their list of strengths while cramming in the alloys. I love seeing these steels way up on Ankerson's edge-holding results list knowing that they also take & hold that super-fine edge like 1095 or 12C27.

 

[Ankerson]

Yes, but you yourself said you couldn't rank your Phil Wilson custom due to the extremely thin edge geometry giving it less starting force than the 15 lbs you normally look for. If the Rc 62 blade was at an edge geometry within an acceptable range, wouldn't that be worth putting on the board?

I personally find I like M390 even more than S90V and similar steels except perhaps when cutting cardboard. It seems to take and keep a razor edge much longer than the other high vanadium steels, as well as S30V. Certainly, it seems like a waste of time to put a mirror finish on those steels. When you're not cutting anything as abrasive as cardboard and the like, the wear resistance of S90V(and similar) aren't noticeable. Even cutting only cardboard(though not the only thing I did during my 8 hour shifts) I found the working edge was more than satisfactory for the better part of 3 months.

I think I see the true appeal of M390. There isn't another stainless steel that really comes to mind when I think of one that takes and holds a razor edge like a carbon steel. Not as tough sure, but the edge it takes isn't lost with a mere few cuts. I went through 20 cases of corn on Friday with my M390 BM 581, and the edge lasted quite a while. My R.J. Martin Overkill in S110V never really had that "air bleeding" sharpness to it, and it dulled to the same level as my M390 blade after about 2-3 cases.

That's not to say M390 has better edge retention than S110V, as I'm sure the difference between the two will be obvious after about 50 cases of corn each. Just that M390 takes a razor edge easier, and likes to hold onto it stubbornly as well. It would be interesting if someone took it one step further to refine the grain structure with a nitrogen 3rd gen PM steel that has 9% vanadium, but only enough chromium to ensure a decent level of stain resistance. I'm thinking Vanax 35 and 75 have too much chromium that would make big chromium nitrides, so those might not take well to a razor edge.

I think CTS-20CP is going to be the nearest thing to that for awhile yet, it's S90V that is 2nd Generation technology.

Vanax 35 is going to be an interesting steel if someone uses it for production blades.

S110V will get sharp, very sharp just like S90V will, it just takes longer to get the extremely refined edge.

ELMAX and M390 are easier to sharpen though, getting them to 62 HRC and how they perform will depend on the the Heat Treatment.

The High percentage Vanadium steels like S110V, S125V 10V, 15V, K294 ect just plain cut forever at proper hardness, the next step down will be S90V, 20CP, M390 and ELMAX at proper hardness.

The problem is we don't really see much of these steels in production blades at high hardness, they are usually customs.

The reason for that is the custom makers know who the knives are for and what they will be used for so they can push the hardness and thin the blades out.

In production blades the Manufactors don't know who the blades are for or what they would be used for so they drop the hardness down and make the blades with thicker edges and grinds.

 

[hardheart]

What's a "bar" Jim? Unit for pressure, or something else we should know about?

Bar is the quench rating of the furnaces, the higher the number the faster it is.

bit of both, the quench rating is determined by the gas pressure of the vacuum furnace.

imo, salt baths are probably superior all around for microstructure and where a custom heat treat with give you the best response from the steel. But it is messy and pricey. And it gets us into diminishing returns pretty quickly when there are plenty of quality furnaces and controllers out there.

Interesting to see that there was the same performance between the steels. We're going to be testing for differences between PM and ingot performance at a knife edge, since the sheets generally show that PM doesn't affect wear resistance, mainly improved toughness and homogeneity.

 

[Ankerson]

bit of both, the quench rating is determined by the gas pressure of the vacuum furnace.

imo, salt baths are probably superior all around for microstructure and where a custom heat treat with give you the best response from the steel. But it is messy and pricey. And it gets us into diminishing returns pretty quickly when there are plenty of quality furnaces and controllers out there.

Interesting to see that there was the same performance between the steels. We're going to be testing for differences between PM and ingot performance at a knife edge, since the sheets generally show that PM doesn't affect wear resistance, mainly improved toughness and homogeneity.

Don't know the hardness on the 20CP yet....

But I do think it would take CATRA to really see the difference between them because it seems to be very small.

Smaller than I can test for anyway.

 

[Ankerson]

Update on the hardness on 20CP, it came in at 60 HRC, same as S90V.