s90v vs. CTS-XHP

No such thing as CTS-M4, there is CPM-M4 and it is very tough as it canbe made into some big old choppers, and it's definitely not corrosion resistant like 90V. I don't think S90V is considered tough the same way M4 is. S90V is pretty much a carbide dominated steel.
 
s90v *should* also have a noticeable advantage in wear resistance over CPM M4. But I must warn I've never used s90v, this is just from all I have read. CPM M4 does have really good wear resistance, though. And that strength seems to really lend a hand in edge stability if you end up hitting hardened steel, porcelain, marble, etc... For instance, I found myself recently cutting a block of aged cheddar with my pocket knives on my counter top (dirty cutting board) I made the SAME mistake on three knives, cutting the same block of cheese, within about a week... I'm carefully and slowly slicing the cheese so that my edge never even touches the marble counter top. But knowing cheese, at one point each time the cheese gave out and the edge slammed the counter top... First blade was ATS 55 and about 1/4 inch of the edge rolled over really badly... Second knife was S30V and a slightly smaller portion of the edge flat spotted quite noticeably. Last knife was CPM M4 and I noticed no edge damage to the naked eye or to the touch. It also seemed to slice paper just as well.

thickness behind the edge, and edge grind could have affected my less than scientific results, btw. But over the years of carrying all these steels, CPM M4 has consistently avoided damage where the others have rolled, chipped, flat spotted, etc...

My favorite steel out of all I have used for sure.
 
broken tip is more an issue of blade profile, thickness, and geometry. I can't speak on the chipping, but I'd hesitate to call it a remotely weak steel. There are some guys who have used their S90V Militaries for really hard construction/drywall type work and I don't remember them having issues. The Military also has a pretty fine, thin tip which would be more prone to being damaged compared to your typical drop point...
 
M4 on mine spyderco gayle bradley is phenomenal,used to cut all kinds of things from cardboard,plastic,clothing,making my homemade grappling dummy,then after a month of use landed it to my better half to cut a smoked pork leg in pieces(60 min of cutting)and after all that no noticeable damage,rolling or chipping.Got the paper to check the slicing went through it like butter.By far my favourite steel too for every day chores.No patina or rusting either.Really good stuff.
 
CPM M4 Krew! haha.

mine has patina, but only because after about a month of carry it had little to no staining, so i started leaving it uncleaned after I used it on food instead of immediately wiping it down. really easy steel to maintain even though it's technically not stainless.
 
M4 high speed tool steel is a very interesting steel. Its far from stainless, but it doesn't rust easily, it can be run very hard (64hrc) and still be tougher than most any stainless steel that exceeds 60hrc. Its tough to machine at that high hardness but at those levels it meets or exceeds M390 wear resistance. At lower hardness, typical of production knives, it offers unmatched toughness for its wear resistance. Its practically made to be used in big, thin knives like what you see in Blade sports. Its one of the best knife steels for almost any type of blade, period.

S90V is very stain resistant, and has an extremely high number of carbides, namely vanadium carbides. It has wear resistance for days and is very stain resistant. Its not tough, due to the sheer amount of carbides, but even at 60-62hrc it is plenty tough for *most* cutting chores. Even larger fixed blade slicers like Phil Wilson is famous for do just fine. If you chip it out or snap it, you were probably doing something stupid.

For an EDC type knife I'll take a good, hard S90V, and for a larger outdoors type blade, M4 is very tough to beat.

Both are time consuming to sharpen without good gear. M4 holds its hair popping edge longer IME than S90V, but if all you need is a great working edge to last a long time, S90V is unreal.

ETA: XHP is a fine steel, but outmatched by both steels mentioned above. Its better compared to S30V or ELMAX or some of the other good mid range steels.
 
S90V has much higher edge retention than the other steels listed.

Here are some results from manila rope cutting (draw cuts) with a coarse edge, all knives at 15 degrees per side.

S90V - 460
M390 - 380
S30V - 300
CTS-XHP - 240
Dozier D2 - 220
VG-10 - 160
AUS-8A - 160
 
Thanks for posting that Ankerson. Its really just a testament to S30V though. What a good steel for so many knives and its a lot cheaper these days due to popularity. M390 is still amazing though. I love the mirror polish it takes and it holds a shaving edge for a long time. XHP is good, and easy to sharpen but outclassed by M390 and M4 and, obviously, S90V.
 
TriviaMonster said:
Thanks for posting that Ankerson. Its really just a testament to S30V though. What a good steel for so many knives and its a lot cheaper these days due to popularity. M390 is still amazing though. I love the mirror polish it takes and it holds a shaving edge for a long time. XHP is good, and easy to sharpen but outclassed by M390 and M4 and, obviously, S90V.
Click to expand...

I would consider M390's edge to hold a hair cutting sharpness for a good while that's for sure, but it looses it's "shaving" sharpness fairly quickly. I believe the carbide content create far too aggressive of an edge. I spent HOURS honing, stropping an M390 blade using 200x magnification. No luck producing a super fine smooth edge. It would nearly push cut TP and cleanly slice TP but it still felt toothy.

CPM-M4 has slightly better edge retention than M390 when it hits 64 HRC and M390 stays at about 62~ HRC otherwise at 62-63 it seems to be at the same level as M390 based on several results I've seen.
In production knives one can be safer to say M390 and M4 should act similar except with M4 behaving differently at the edge than M390.

I only touched up CPM-M4, haven't given it my best sharpening yet with 200x magnification but so far it seems to behave interestingly and under the microscope looks far different from M390 or similar steels.
When you finish polishing the edge (honing/stropping) it feels as if it is getting sharper as you cut cardboard for the first few cuts, then it begins to dull out (slowly I may add).
 
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