What steel will hold a 25 degree inclusive edge the best?

I just got a Benchmade Barrage at a local hardware store. I wasn't planning to buy a knife, but I saw this model with a beautiful aluminum bolster and G10 scales that I just had to look at. Once I snapped it open (it's an auto), I could immediately see that the blade and edge geometry were awesome. Thin blade. Very thin edge. Pointy point. And the steel was M390.

When I got it home, I checked out the specifics. The edge angle is 22 degrees -- and this is a factory edge that is very sharp. The width behind the edge is just 0.0155 inches. This thing reeks with quality and cuts like a demon laser. Might be what the OP is looking for -- great steel, great geometry, great knife.
 
I must say that I own a s30v para 2 and when first used the edged chipped very easily, at first I was upset that this expensive knife I bought chipped so easily. And it wasn't until I sharpened the knife prob 3 times that it didn't chip at all, my own conclusion is that the FACTORY edge is while very sharp the process in how they are sharpened ruins the tempering right at the edge and after a few sharpenings by hand removes the bad steel. To me it doesn't matter how sharp an edge is from the factory the chances are a few sharpenings are required before seeing the true characteristics of the steel. There is a you tube video of this with a spyderco nilakka that has a zero grind. People saying that the steel is garbage and spydercos ht is bad but that's not the case. I find my s30v very hard to chip now after a bit of sharpening.
 
A dry hardwood branch can be a challenging medium to cut with a knife.

Don't dismiss 440C. Properly heat treated it's a good knife steel. Way back when I had a S30V Griptillian, I whittled a hardwood branch soon after getting it and the edge chipped out so much it looked like a cheap serrated kitchen knife. The behavior persisted through several sharpenings. The replacement knife Benchmade sent didn't do much better on the same branch. Maybe it's the branch...

So I did an experiment with my other Griptillians in different steels on that same branch. Same number of slices with each knife, same angle, same thickness of chip, or at least as consistent a test as I could do by hand. I sharpen all my knives using a guide, at an included angle of about 25 degrees. I tested D2, 154CM, M2, and 440C. All the knives got a few small chips in the edge, except for the 440C which was almost as sharp after the test as before. YMMV, and this is a fairly unscientific test on one unknown hardwood branch, but based on this I would suggest trying 440C, or a good carbon steel (25 degrees is a common included angle for carbon steel chisels and plane irons, and I've seen plenty of those cut hardwood without chipping)
 
Try some Sanvick 12c27. Mora uses something similar and sharpens to roughly 10 degrees per side. For your described light use (a little rope, some stake whittling) there arent many steels that shouldn't be able to do more than you describe. If all else fails, I have some Japanese mystery stainless that will cut copper wire and aluminum cans and stay sharp at 14 degrees inclusive with a 20ish inclusive microbevel.

All that said, I dont think its the steel, or at least its not all the steel. There is some unknown sharpening issue, the wood is very dirty, your standards are unusually high, etc.
 
Oh, and twindog I think posted on the first page regarding powder steels having finer carbide size. Just for clarification, finer than what?
 
What I said: "Powder steels can generally be taken to a higher hardness, have better wear resistance and offer finer, better distributed carbides that are less likely to be ripped out and appear as micro chips."

The key advantage of powder steels is that their carbides are finer and better distributed than their ingot counterparts and other high-alloy ingot steels. I have read where Ed Fowler can greatly reduce carbide and gain size in 52100 with an extremely elaborate heat treat, but for the high-alloy steels, the powder process is what makes them so useful for knife applications. As carbide volumes increase, the carbide loads tend to be large and clumpy in ingot processing, meaning they are prone to breakage, chipping and other damage.

From various posts here, I'm also getting the sense that sharpening techniques and sharpening media can make a large difference, but I don't know how to form that sense into a coherent theory.
 
I've tinkered/experimented with various steels from simple carbon to super high alloy (1018 through cpm-rex121). Carbon & semi-stainless & low-alloy stainless are capable of sustaining 12.5dps for OP's requirement. It needs properly ht + geometry for ingot or particle steels. For an instance, here is a thin slicer-ultility made with ingot D2 (src from Aldo/NJSteelbaron). I broke down 2 whole chickens (costo 2 organic chicken pack) into small grill size chunks - through all bones except leg/thigh. Bone cut & fracture sometime not in straight line, thus impart quite a bit of lateral damaging force to the edge. Obviously this knife has fine grain & fine carbide, otherwise D2 edge deformation is guarantee. My crazy guess carbide size at 1um or smaller, since larger carbide can't support 10dps at any hardness for this type of tasks. Oh well, blah my words, at least here is a choil shot pic :p

SU D2 choil view.jpg

edit: correction - this blade hardness is 64rc not 62rc.
 
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I was wondering if you were comparing the CPM/PM steels to their ingot counterparts or to other lower alloy steels.

Bluntcut, how are you judging carbide size? What did you do to reduce the size, as ingot D2 is widely known to have some fairly large carbides.
 
Carbide size determination/guessing by induced-carbide chip/tear-out by finish sharpened this blade on a 8K waterstone. Use this thin geometry & acute angle to saw into dry oak knot, then look under a 400x (~50x linear) usb microscope. Triangulate with other blades in different steels s90v, 20cv, s30v, 52100, w2, 1095 to come up with guestimate carbide size for this blade. Plus induce smallest smoothest(would be perfect apex) wire-edge possible, in itself tell tale of grain & carbide size. Burr/wire tendency to form/hinge on object boundary, i.e. carbide and grain boundary.

ht with multiple thermal cycle - concept as follow

repeat (up to 9 times): max diffusion - stair step downward from high aust temp; more & more uniform element distribution per cycle + more nucleation points; diffusionless transform to prevent element aggregation.

hardening+quench: proprietary

btw - my super quench blades didn't perform as well as non-super-quench above. Still they are way better than baseline ht(high end aust temp per mfg suggested) blades + cryo (dip and or long soak). These baseline blades won't support sub 13dps and will grossly chip when hardness is 62+rc.

me2 said:
...Bluntcut, how are you judging carbide size? What did you do to reduce the size, as ingot D2 is widely known to have some fairly large carbides.
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I have sample of bluntcut's 52100 at 10-15 dps (or even less, difficult to measure as it's convex) and no chip & roll from normal use, dulling by wear only so far. :thumbup:
 
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We've discussed stuff like this before. I'd be very careful about attaching any degree of certainty to a claimed carbide size of 1 um or so in D2. As they say on the innerwebz, pics or it didn't happen.
 
No micro/nanographs however I am willing if you cover the cost of Element's for metallography & analysis services ;) Until/otherwise give me benefit of doubt or disregard 'em as bull:p Interwuz after all...

me2 said:
We've discussed stuff like this before. I'd be very careful about attaching any degree of certainty to a claimed carbide size of 1 um or so in D2. As they say on the innerwebz, pics or it didn't happen.
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In his 1998 book, Knife Talk, Ed Fowler described an elaborate heat treat and forging of a bar of virgin 52100E steel that took many, many days, involving careful heating (by the blacksmith’s eye — Rick Dunkerley), 24-hour soaking in liquid nitrogen, reheating in the kitchen oven, various types of cooling/quenching, many tempering cycles, etc.

The resultant knife had a 300-percent improvement in cutting performance, and the toughness was almost beyond belief. The blade from this process was flexed back and forth 180 degrees more than six times before the edge cracked.

The blade was sent to Metallographic Laboratory Services for analysis. The edge was 58 Rc. The spine was 30 Rc. The steel had no retained austenite, and the carbide size was between 0.5 and 1.0 microns.

And all of this was done without the high-tech advantages of today’s steel processing and heat treating.
 
Ed's processes are something to behold. However, 52100 and D2 are very different. It's worth noting that standard industrial processes produce smaller carbide sizes without the complexity.

Bluntcut, do you use Element labs? I've used them since before they were Element. Do you have an estimate for microscopy and carbide size analysis? I have no doubt that there are some 1 um carbides in your D2, but the average size is likely much larger, maybe 10x.
 
Ed's processes are something to behold. However, 52100 and D2 are very different. It's worth noting that standard industrial processes produce smaller carbide sizes without the complexity.

Bluntcut, do you use Element labs? I've used them since before they were Element. Do you have an estimate for microscopy and carbide size analysis? I have no doubt that there are some 1 um carbides in your D2, but the average size is likely much larger, maybe 10x.
 
I ordered a 550 grip yesterday, and I'm ordering scales from the Russian next week. The production scales are just to fat for me. Hopefully this knife will work, it should on paper. After the custom scales its everything I like in an edc. Hollow ground, three and a half inch sheep's foot blade with spydie hole and axis lock. Couldn't ask for more, and if it doesn't hold the edge at least its easy to re-sharpen.
 
By the way Twindog, that barrage has been on my list for quite some time now. I'm jealous. So many knives, too many hobbies. Summer's all about fishing for flattie's and winter is all about knives and coyotes. Winter is coming....lol.
 
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I'm still kicking myself for getting rid of my grip. You'l have to lower the edge angle though. Mine came with about a 25 degree edge per side.
 
Not yet but plan to use them at sometime in the future. No quote - but I expect $1-4K for what I want to analyze the first time. Subsequence time, I probably just want nanograph done various electron & atom microscopes.

Most of cpm steels (including 3v) won't support a hard sharp working edge below 12dps. Their carbides size range between 2-5um. I can only guess/project that my D2 & K110 carbide size in 1um or smaller because these knives will support stable edge from 7.5dps and up. Keep in mind that at 7.5dps (straight razor), most carbon knives(and low Cr) will have tough time support a stable edge at this acute bevel.

me2 said:
Bluntcut, do you use Element labs? I've used them since before they were Element. Do you have an estimate for microscopy and carbide size analysis? I have no doubt that there are some 1 um carbides in your D2, but the average size is likely much larger, maybe 10x.
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