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

darrin sanders said:
Knowledge of the way a knife is H/T'd has nothing to do with how it actually cuts. A certain company's H/T procedure is what it is and you can't change it. Knowing how its done (good or bad) does nothing to change the way it cuts. That's the whole story.
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Knowing doesn't change the fact, but the fact itself impacts performance. Knives of equivalent geometry, equivalent steel, but HT'd differently will perform quite differently depending on the test (as is being discussed above). In this case, high-carbide steels can be optimized for wear-resistance but lack toughness needed for edge-stability in other media, or corrosion resistance needed for other environments, or they can be optimized for a mix of attributes. The way a knife is manufactured and HT'd has a LOT to do with how it actually cuts, whether you know it or not. The more users know about it, the more they can advocate for products optimized for their needs. Otherwise why bother with expensive knives at all? I can grind a 10C thrift-store knife to a razor's edge, that doesn't grant it the wear-resistance or edge-stability of S110V HT'd well and given similar geometry. Or why pay the same price to one maker over another for similar knives in the same steel if one maker does not optimize the HT-protocol and the other does? Will they cut the same? In some tests, perhaps. Will you notice a difference? Some might not, but others might. *shrug* You hear talk of "chippy" steels all the time when an altered HT protocol would eliminate the fuss. I, for one, like the added information, even if only for my own edification.
 
chiral.grolim said:
Knowing doesn't change the fact, but the fact itself impacts performance. Knives of equivalent geometry, equivalent steel, but HT'd differently will perform quite differently depending on the test (as is being discussed above). In this case, high-carbide steels can be optimized for wear-resistance but lack toughness needed for edge-stability in other media, or corrosion resistance needed for other environments, or they can be optimized for a mix of attributes. The way a knife is manufactured and HT'd has a LOT to do with how it actually cuts, whether you know it or not. The more users know about it, the more they can advocate for products optimized for their needs. Otherwise why bother with expensive knives at all? I can grind a 10C thrift-store knife to a razor's edge, that doesn't grant it the wear-resistance or edge-stability of S110V HT'd well and given similar geometry. Or why pay the same price to one maker over another for similar knives in the same steel if one maker does not optimize the HT-protocol and the other does? Will they cut the same? In some tests, perhaps. Will you notice a difference? Some might not, but others might. *shrug* You hear talk of "chippy" steels all the time when an altered HT protocol would eliminate the fuss. I, for one, like the added information, even if only for my own edification.
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Thanks chiral.grolim .
At least my efforts to explain what you mentioned -at the known risk of being filed for thread hijackin' :) - had left one mind enlightened.
Actually enough, after having left stock edge on two costy (in Italy 600EUR for both) production folders in CTS-XHP (both 60.5) time has come to resharpen them (I let them both intentionally go dull) and get rid of some early pit rust starting points (that were expected ASA I learned about their HRC value).
I expect wire edge issues.
 
So no one has actually used the high-Cobalt HAP steels (HAP40 or HAP72) to compare them with western equivalents? The only place I've seen them is on some fairly high-end Japanese chef's knives.
 
HAP40 is different then CPM M4 as it has a fair amount of Co 7.5-8.5% and M4 has none. Hap40 has more W,Cr,Mo, and a hair less V and C. I think it would make an excellent slicing blade based on composition. I have yet to hear of a steel to top B.U K294@64 HRC in a slicing blade.
 
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waterstoneblades said:
HAP40 is different then CPM M4 as it has a fair amount of Co 7.5-8.5% and M4 has none. Hap40 has more W,Cr,Mo, and a hair less V and C. I think it would make an excellent slicing blade based on composition. I have yet to hear of a steel to top B.U K294@64 HRC in a slicing blade.
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Ehm, HAP40 is just the same thing as Vanadis 30 and straight from BU datasheet.. "The
presence of cobalt has little influence on wear resistance. As cobalt does not form carbides, the wear resistance of Uddeholm Vanadis 30 is more or less the same as for steels with the same base analysis but without cobalt (e.g. Uddeholm Vanadis 23). On the other hand, its presence reduces the toughness and hardenability somewhat but increases compressive strength and high temperature properties.".

So, CPM-M4 or equivalents are perfectly comparable -wear resistance wise- to HAP40 and equivalents. CPM-M4 will perform same wear resistance, lower maximum HRC values (-2HRC), higher toughness.
Roughly speaking HAP40 class and CPM-M4 will score a total carbide content in volume of about 12%: 8% of those carbides are the very small tungsten/molybdenum carbides, and 4% will be vanadium carbides.
Roughly speaking I endorse high Cobalt content into cutlery steels if this steel in plain old ingot melted steel (N690) as it refines grain size.
In PM steel the grain size is fine by definition (at least in 2nd and 3rd gen). The small ultimate increase in hardness at the price of toughness, typically confine HAP40/Vanadis 30 in somehow limited niches of tasks.
 
HAP40 can be used in the 64-68 HRC range. The edge retention should be better then CPM M4 with the cost of some toughness IMO. Co, intensifies the individual effects of other elements in more complex steels. Adding cobalt to the alloy allows for higher attainable hardness.
 
waterstoneblades said:
HAP40 can be used in the 64-68 HRC range. The edge retention should be better then CPM M4 with the cost of some toughness IMO. Co, intensifies the individual effects of other elements in more complex steels. Adding cobalt to the alloy allows for higher attainable hardness.
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EDIT 28/07/2014:
Reading the datasheet of BU Vanadis 30, it should have toughness in between CPM-M4 grade and M2 grade.
Crucible has this table, where M3+Co (CPM Rex 45) has even less toughness than M2 and slighly less wear resistance than CPM-M4 (although I do suspect that they are talking about Adesive Wear Resistance):
http://www.crucible.com/eselector/prodbyapp/highspeed/highspeedchemtbl.html
More in depth data can be found in the CPM Rex 45 Datasheet
Notably:
Hardening/Tempering/Hardness/Toughness (Charpy Impact C-Notch ft.lb. (J))
Temp.
°F (°C)
2175 (1190)/1025 (550)/67/15 (20)
2150 (1175)/1025 (550)/66.5/18 (24)
2125 (1165)/1040 (560)/65/20 (27)

Just as a quick comparison:
CPM M4 will have 27J at 65.5HRC, 38J@63.5 and 43J@62
Crucible M2 will have 23J at 64HRC, 26J@63 and 28J@61
CPM 10V will have 20J at 64HRC, 22J@63 and 30J@61. When at 60HRC it delivers more than twice the wear resistance than CPM-M4 @62HRC

My own conclusions:
Per Crucible Rex 45 datasheet it will have a 12% more wear resistance than CPM-M4 by sheer increase in HRC.
CPM-10V at comparable levels of toughness will hold an edge way longer than Rex45.
 
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Pretty much what I thought. It would be nice if they would upgrade their steel, or if nothing else, just increase the hardness if possible. As thin as Opinels are, it would never be hard to sharpen.
 
sodak said:
Pretty much what I thought. It would be nice if they would upgrade their steel, or if nothing else, just increase the hardness if possible. As thin as Opinels are, it would never be hard to sharpen.
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Yeah they could do that for sure, I would say a few points at least on the carbon steel....

Have to figure they are $13 knives so I am not sure how much doing a steel upgrade would effect the prices, I know they have handle upgrade options that do get expensive compared to the original prices..
 
Ankerson said:
Well, it depends on what your normal use is, .005" behind the edge is VERY thin...

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Compared to the Native 5 in S110V (.030") and S110V Mule team (.015")....

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But yes, cutting things it's fine, here is about 3/4 Mile of cardboard that was cut, that's 3800 ft , 1266 yards of cardboard and it would still slice printer paper. That's with no edge damage, chips, rolls etc......

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This is awesome, now the question I have for you, where do I go I learn how to make my s110v manix like this? What's the best tool for the job
 
Hey Jim:

I'm a big fan of your testing and appreciate how your testing has given us a decent sense of how various steels stack up to one another in wear resistance. One of the surprises for me was how Bob Dozier's D2 has ranked. I would have guessed that it would have performed better, given Dozier's well deserved reputation for wringing every advantage possible from D2 with his heat treat. You are probably also following Me2's excellent thread on fine grain vs fine carbide steel performance.

I've been convinced that powder steel and spray forming processes can bring out even better characteristics -- better toughness and wear resistance -- than ingot D2, which is what I believe Dozier uses. Power D2 (CPM D2) and spray formed D2 (PSF27) have the same carbide volume as ingot D2, but that carbide volume is expressed as smaller, better distributed carbides, improving both toughness and wear resistance.

I know you get a lot of requests for more tests, but if you have the energy and inclination, I'll give you my PSF27 Mule (spray formed D2) if you would like to test it. (You deserve something for all your work.) My expectation would be that SPF27, with Spyderco's heat treat, would outperform ingot D2, even when heat treated by the master Bob Dozier. I know you don't test for toughness, although your tests cover more than just wear resistance. Still, it would be nice to put these marketed advantages to the test.
 
Twindog said:
Hey Jim:

I'm a big fan of your testing and appreciate how your testing has given us a decent sense of how various steels stack up to one another in wear resistance. One of the surprises for me was how Bob Dozier's D2 has ranked. I would have guessed that it would have performed better, given Dozier's well deserved reputation for wringing every advantage possible from D2 with his heat treat. You are probably also following Me2's excellent thread on fine grain vs fine carbide steel performance.

I've been convinced that powder steel and spray forming processes can bring out even better characteristics -- better toughness and wear resistance -- than ingot D2, which is what I believe Dozier uses. Power D2 (CPM D2) and spray formed D2 (PSF27) have the same carbide volume as ingot D2, but that carbide volume is expressed as smaller, better distributed carbides, improving both toughness and wear resistance.

I know you get a lot of requests for more tests, but if you have the energy and inclination, I'll give you my PSF27 Mule (spray formed D2) if you would like to test it. (You deserve something for all your work.) My expectation would be that SPF27, with Spyderco's heat treat, would outperform ingot D2, even when heat treated by the master Bob Dozier. I know you don't test for toughness, although your tests cover more than just wear resistance. Still, it would be nice to put these marketed advantages to the test.
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You can send it. :)

I will run it, no problem.

Don't know what it will do until I test it and see. :)
 
I don't know how to search a specific thread, and forgive me for not having read all of the near 100 pages of this very interesting topic, but was interested to know if you've tested a SAK blade? If not, would you be willing to, I don't know of anyone else, but I would find it interesting to see how it fares.
 
I think that the SAK would perform similarly to the Inox Opinel that Jim recently added to the list.
 
Awful quiet around here, since the MT19 came out. I'm eager to see if PSF27 is just about equivalent to CTS-XHP, in this test format, even though the thickness behind the edge would seem to favor the MT19.
 
deskil said:
Awful quiet around here, since the MT19 came out. I'm eager to see if PSF27 is just about equivalent to CTS-XHP, in this test format, even though the thickness behind the edge would seem to favor the MT19.
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It's coming up, have it reprofiled and sharpened for testing.
 
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