Blade Material

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I like CPM-420V, BG-42, or CPM-440V mostly for use!
They all hold an edge very well, not brittle, and have excellent rust resistance qualities.

As far as forging goes, don't know about that but I have heard that these 3 steels are tough when it comes to that!

TitaniumKnutt
 
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You can NOT forge CPM420V or 440V. The very nature of their manufacturing and alloy composition makes that impossible. Their carbon content is so high (over 2%) than heating to forging temperatures would turn the steel into wrought iron.

That said, my current top three list for blade steel in small 'stainless' pocket folders would be 420V--->D2--->BG-42

If you are willing to accept carbon steels, my list would add 52100--->5160---->1084

All of these 'carbon' steels will take a better edge and hold it longer than high chromium steel except (maybe) 420V.

Paracelsus
 

Old Knife Guy

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To Paracelsus: I have always liked 154-CM for my knives. Long before I learned Bob Loveless preferred this blend, I thought it sharpened easily on my Edge-Pro, shined up very well, and held an edge for 'normal' cutting. Considering the premium price paid for knives of S60V (and my wife has one, and it is sharp and holds an edge) aren't people in the real world served better by more common steels? (And I don't think 154-CM is 'common.' I think it represents a proper balance.)--OKG
 
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I like ATS34/CPM154 also. All blade steels are compromises of conflicting properties (stain resistance, edge holding, toughness, cost, etc).

The thread asked about the Best blade steel. Any question asking about the Best anything displays a lack of understanding of the complexity of the issues. There are plenty of other really good blade steels. As far as stainless steel goes, I think CPM420V/S90V is about as good as it gets right now. But it is Very expensive and harder to finish well. And just because 420V is good, it does not make other good blade steels 'bad'.

I am actually a carbon steel fanatic and have rarely found any stainless steel to take or hold an edge as well as many carbon steels. But I recently purchased a 420V folder. That steel in a small pocket folder seems to me to be just about ideal, but costly.

Paracelsus, clarifying my position
 
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Quoted by Paracelsus: You can NOT forge CPM420V or 440V. The very nature of their manufacturing and alloy composition makes that impossible. Their carbon content is so high (over 2%) than heating to forging temperatures would turn the steel into wrought iron.

Thanks Paracelsus for clearing that issue up. I really wasn't aware regarding forging of these steels, but for blade material I like those much so.

 
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I've got a piece of 440V that I've forged. I set it aside because it has been the most red-hard chunk of steel since the last blade I did out of D2. It's NOTHING like wrought iron, though. Decarb hasn't shown to be that bad. I won't know how useful it is until I've finished it, but I'll let you know.
I'd have to go with Paracelsus' list for steels, and add Talonite to it, even though it's not a steel.

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Old Knife Guy

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Response to Para: I understand your comments. My point is that as an average American at 50 years old, I don't put near the stress on a knife that some are designed for. For example, my average day consists of opening envelopes, boxes and trimming loose threads. While I can be served by knives like the Spydie Michael Walker (which I liked) or a CS Voyager plain clip point, I like nice, well made things.
For years I carried a clip point MT mini-SOCOM and a 910SBT (Stryker) to the office. The MT had a purple handle and clipped to my front pants pocket and never raised an eyebrow from the sheeple. Weekends saw me with a SOCOM Tanto in my jeans. (As remote as it sounds, Wisconsin has no CCW license, and while I'm careful where I go, I must admit the Tanto had a self-defense role.)
For yearly vacation trips to the boonies, I toted a titanium BM 970ST. I chose that model because I never knew what I might have to cut or when the knife could be properly cleaned.
None of these knives was really the 'perfect knife.' They were either too big, too small, too spooky to sheeple, a chisel grind or too expensive for daily carry.
I now carry a LCC. I don't need the edge retention of S90V since my Edge-Pro is at home. It cuts as well as a Tanto. It's bigger than a mini-SOCOM. In a pinch, it could save my hide.
For me, I had to admit I'm not Rambo or James Bond, and the expense of buying a S90V knife just to be be macho seems foolish. Don't you think the steel should match the man?--OKG
 

Bronco

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Para,
CPM 10V is 2.45% carbon and it has been successfully forged by Rick Dunkerley. Will York has the blade if you're interested.
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-Bill
 
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Evidently I may have been wrong about CPM steels not being forgeable. I am curious to know what sort of temperatures were required to forge that that material, and if the desirable properties locked into CPM steels during their making would be significantly altered by forging.

My understanding is that the particle metallurgical process 'freezes' the molten material into very hard vanadium and other types of carbides. In the case of 'stainless' CPM steels with a high chromium content, the process leaves most of the chromium 'free', not bound up in carbides. The carbon content is in the range that would normally make the steel 'unhardenable' without the PM process. Most of the excess carbon ends up making hard carbides. Applying high heat to these materials will significantly change the mixture of carbide crystals in the steel, making it into something else altogether.

Maybe after forging it remains a good blade steel, but is it still the same, or as good as the unforged material? I dunno. My knowledge base may be insufficent. I probably should not have made that comment about forging CPM steels. Is there a difference between forging low chromium and high chromium CPM steels?

Anyone else know enough to explain this to me and everyone else?

Paracelsus, always learning
 

Danbo

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Those steels may be forgeable, but there comes a time when the work involved is not worth it. There is probably not a lot to be gained from forging something like 420V, and I'm sure the people who have forged it are not in any hurry to do it again.

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Danbo, soul brother of Rambo
 
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Forging specs for T440V
Heat slowly to 2100F
Do not forge below 1750F.
cool slowly.

And for 3V
heat slowly to 1900F-2100F.
Do not forge below 1850F
cool slowly.
both must be fully annealedafter forging.



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Ok Ed, so you Can forge the stuff. BUT, is it still the same stuff after forging, annealing, hardening, and tempering?

How is hardening of these steels accomplished? Rapid cooling, or air quench?

Has anyone compared the properties of a forged CPM steel to the same material shaped only by stock removal? Are they different?

Paracelsus, really confused

[This message has been edited by Paracelsus (edited 11-30-2000).]
 
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All the premium blade steels and materials are good. Find the maker that makes the knife that suits you based on design, fit, and finish, then take whatever he likes to use. It doesn't matter much.

CPM 420V is my favorite for folders. It is pretty tough, pretty stain resistant, and holds an edge a loooong time. But if I liked the design and quality of the knife, I would be perfectly happy with 440C, VG-10, ATS-34, ATS-55, 154CM, M-2, D-2, 52100, CPM440V, Stellite, or Talonite. As long as the maker knows how to get the most out of it, there isn't much practical difference between the premium blade materials.
 

Bronco

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Para,
My understanding of the CPM process pretty much follows along the lines of what you've described. The steel begins the process in a molten state very similar to that which is seen in conventional steel making, except that the CPM steel contains higher levels of carbide forming elements than can be supported using conventional methods.

The molten steel is then sent through a nozzle and essentially atomized such that a flash hardened powder of 'micro ingots' result. Because of the small size of these individual powder particles, and the speed in which these particles freeze, the alloying elements don't have time to segregate and clump together as would happen if the steel was poured and allowed to cool in larger ingots. Not only are the carbide grains more evenly distributed throughout the steel, but they are also smaller in size.

These individual powder particles are then recombined using the hot isostatic pressing (HIP) process, a high pressure treatment which, interestingly enough, subjects the steel to temperatures very close to those which are encountered in forging. According the folks at Crucible, the fine grain structure and even distribution of the carbides within the steel are preserved through this process. It may well be the case then, that this fine grained, homogenous steel is able to survive similar treatment at the knifemaker's forge.

As to the question of the quenching process, Crucible recommends the following for 420V:

"Salt quench, interrupted oil quench, positive pressure gas quench or air cool at a minimum cooling rate of 150F/min to below 1000F followed by still air or moderately forced air cooling to below 125F".

I doubt this answers all the questions, but it's a little more data for the discussion.
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-Bill
 
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I'm with Steve Hatvey on this one. All the premium steels are good. Get a knife that has the design features and workmanship you desire and you will more than likely be very happy with it.

Paul

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I very much like 154CM, 440C, A2 and O1. I also like Stellite although technically this is not a steel.
I do agree that any of the good blade materials will make a good knife as long as it has been properly heat treated.
The use the knife will be put to will have a lot to do with the material that you choose. If corrosion may be a problem then stainless, Stellite, Talonite or Dendritic blades would be a great choice. If not then good carbon steels hold an edge well and are easy to sharpen, and polish up very nicely.
 
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