Ranking of Steels in Categories based on Edge Retention cutting 5/8" rope

Jim, I had a brief but interesting conversation with the BU USA rep at Blade about Elmax and M390. Apparently, the gap between them as far as abrasion resistance goes gets significantly narrower when you get your Elmax above 60Rc. The figures he had indicated that while you do give up some of the relative (for stainless that can actually take and hold a good edge) toughness of Elmax, it is not a huge drop off and it is still tougher than comparable M390 with no worse than 80% of the abrasion resistance. That is pretty significant for a steel that seems to be designed more for toughness.
 
Thanks for the info Joe. M390 is my first choice for ~5in and under blades and I think it might be the best stainless out there right now. Its balance of edge retention, toughness, stain resistance, and ease of grinding/ sharping is tough to beat. I run M390 at 62 right now and im impressed with how tough it is and especially impressed with how stainless it is. I have a M390 nessmuck that a screwed up and decided to keep for myself for testing. Ive put that thing through the ringer. At 62 with a 30A + scotchbrite finish its insanely stain resistant. I've cut lemons with it and left it uncleaned overnight and it only developed small amounts of surface rust that were easily wiped off with a sponge.

I have it at about .016 behind the edge and have had zero problems with chipping even with tough cuts into wood with some torquing. Ive also batonned it many times with no damage. I think at 62 its about as tough as D2 according to the charpy numbers.

I really like ELMAX as well but usually end up using M390 because I want more wear resistance. I think ELMAX is a great choice for 6-8in blades where stainlessness is needed. I'm also interested in using it for some dive knives and would like to know what HT protocol will result in the best stain resistance. Can't seem to find the info anywhere.
 
jdm61 said:
Jim, I had a brief but interesting conversation with the BU USA rep at Blade about Elmax and M390. Apparently, the gap between them as far as abrasion resistance goes gets significantly narrower when you get your Elmax above 60Rc. The figures he had indicated that while you do give up some of the relative (for stainless that can actually take and hold a good edge) toughness of Elmax, it is not a huge drop off and it is still tougher than comparable M390 with no worse than 80% of the abrasion resistance. That is pretty significant for a steel that seems to be designed more for toughness.
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Yes I know. :)
 
My 0561 holds a fantastic edge. It doesn't chip and Kershaw claims a 60-62hrc. I've been very impressed with ELMAX, its one of the best all around steels out there. Plus it still has that new car smell unlike the more common S30V. I would be curious to know exactly what the 0560s come in at Hrc wise. I'm guessing closer to 60 than 62, unless it really is that tough.
 
The Mastiff said:
I've always wondered if those knives he made at rc 68-70 for people in that rex 121 could keep up with the highest performing of Jim's customs in A11 class steels. They may not have 40 something percent carbide but they can slice with excellent geometry due to sufficient toughness at full hardness and not start self destructing the edge on the rope Jim uses.

In the right circumstances rex 121 will have much greater abrasive wear resistance than A11 class steels but I don't believe 30 degree angles and , what, less than .01o edges will hold up with those Rex steels cutting that tough fiber.
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Rex-121 actually has about 41% carbide volume, according to zknives. I don't have any hands-on experience with the steels, but from the composition, I don't think Supracore would be very different in overall performance. In fact it would seem that REX-121 would have higher wear resistance due to the Tungsten and Cobalt content that Supracore substitutes with Chromium, at equal hardness, which again, REX can match point for point. As far as I know, toughness is similarly low. The REX-121 mules seemed to do quite well from what I've seen though, leading me to believe it is tough enough for considerate use. Of course, 10v appears to be both cheaper and maybe a bit tougher while being able to take a finer edge, so it's really a battle for runner-up, at best.

I believe knives in carbide-replacement alloys will become very sought after for performance-oriented collectors in the future, especially if they don't take off and there are just a few made. (I know I want one!).

EDIT TO ADD:
Thanks again for the effort Jim, and I'm still hoping to see more non-stainless alloys tested, especially 1095, W2, O1, A2, etc.
 
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Ankerson said:
I have a knife coming to test in Vanadis 10 @ 66 RC, should be next week, that and the CPM S90V/CPM 154 Composite.
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CTS 204P turned out great!thanks for the update. Vanadis 10 @ 66 will be interesting to see how it compares with k294 @64. When you get up that high in edge holding I wonder if you can tell the difference?By the hardness alone , vanadis 10 should come out on top if there is no edge issues. The laminate blades sound interesting. A niagara steel rep said as long as the heat treat of each grade are within range of each other they will work. I would like to see CPM 3v with a high vanadium core like 10v or better.:)
 
JNewell said:
But it probably would have been a surprise if it didn't land in the same category as M390. :thumbup:
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Given that M390 landed itself in Cat 2 with just half a point difference in hardness, the most telling info gleaned from Jim's testing is that Spyderco is running the CTS 204P at least at 60!

JNewell said:
Great and fast work, thanks! :thumbup: Any plans to have it tested for hardness? (I realize it's a loaner.)
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Jim, if you do want to get it tested, you have my permission. I myself am curious as to the hardness of this run of 204P so if you are able to get it tested, I would not mind! The same goes for the CTS B75P mule I loaned as well, although I heard that those had a target hardness of 62-63 so that is less a mystery. Thanks for the tests Jim!
 
Invective said:
Given that M390 landed itself in Cat 2 with just half a point difference in hardness, the most telling info gleaned from Jim's testing is that Spyderco is running the CTS 204P at least at 60!



Jim, if you do want to get it tested, you have my permission. I myself am curious as to the hardness of this run of 204P so if you are able to get it tested, I would not mind! The same goes for the CTS B75P mule I loaned as well, although I heard that those had a target hardness of 62-63 so that is less a mystery. Thanks for the tests Jim!
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Invective, we all owe you a big thank you for loaning your knife to Jim for testing! On the other points, there are at least two things that separate the two M390 results (Jim could comment much better) - the first is the Rc level, but the second is that different blades can return different results depending on blade thickness, profile and geometry. Unless the blades are essentially identical, you're testing more than just steel, you're testing the blade as a whole: steel, hardness and thickness/profile/geometry.
 
"All the knives started at 14 ~ 15 LBS of down force except for M390 because it cuts so aggressively." (taken from the test explanation) Jim, I don't want to assume 204P cuts aggressively like M390, but did it?
 
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JNewell said:
Invective, we all owe you a big thank you for loaning your knife to Jim for testing! On the other points, there are at least two things that separate the two M390 results (Jim could comment much better) - the first is the Rc level, but the second is that different blades can return different results depending on blade thickness, profile and geometry. Unless the blades are essentially identical, you're testing more than just steel, you're testing the blade as a whole: steel, hardness and thickness/profile/geometry.
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Ehh I didn't really do anything except spend money, Jim's the one who has done everything! All thanks should be showered upon him.
 
nccole said:
"All the knives started at 14 ~ 15 LBS of down force except for M390 because it cuts so aggressively." (taken from the test explanation) Jim, I don't want to assume 204P cuts aggressively like M390, but did it?
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Wow! You read my exact thoughts on that one! I'd like to know this well.

Also, from what I'd gathered, the spyderco brown medium stone (or a similar finish) will give M390 a nice toothy, aggressive, cutting edge that will last longer then any other edge at any reasonable angle? Am I correct in thinking this? I also know that what I'm cutting will have a big role in edge retention. These two knives (PM2 M390 and HTM Gunhammer in M390) are currently in my edc rotation and will be used to cut anything from packaging tape to tie wraps to thin gauge metal if the need were to arise. Both are currently sporting a 40 degree micro bevel, fwiw.

I also have another question, which I think would have the best chance of getting answered here. Has anyone ever done a hardness test on the two Spyderco Gayle Bradleys? Both the large knife and also the Air as I own both and am really curious. Also as a follow up to that, what would be the best working edge for the M4 in the larger of the two Gayle Bradleys? This knife is only just entering my edc rotation and still sports a factory edge. It will be used for the same purposes as mentioned above.

The Air's blade has been convexed, then acid etched, and finally a 40 degree micro bevel was applied. The Air will be carried only situations where a larger folder cannot be. Such as a wedding that I recently attended so edge performance isn't a huge deal here. I will add though that the edge that's currently on the Air is stupid sharp and I'm rather proud of it. :-)
 
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