I might have to slightly disagree with my freind Blue, the differences in knife steel can mean having to sharpen once or twice while field dressing a deer, or being able to dress out 2 or 3 Elk before having to resharpen. Of course I'm a Knife and Gun nut so the little differences probably matter more to me than most........DJ

This is not about steel used on knives, but in industrial aplications. You can see big difference between "old and new school" (D2, A2 etc. vs. Crucible powder steels).



http://www.crucibleservice.com/casehist.cfm



And if your knife is made of CPM-3V or CPM-S30V, you will ged better toughness and much better edge holding etc . . . This is like comparasion .45 muzzleloading rifle to .460wby magnum . . .



Jiri

I have to agree with Jiri on the comparison. 440, 440A, and 440C are not even in the same class.

Typically Chromium has two effects ... inprovement in the corrosion resistance and it changes in the hardening characteristics such that the hardening is completely through the steel without very great care during the hardening process.

Vanadium changes the crystal formation resulting in carbides being layered in veins that help edge retention.

D2 has been described as making a decent blade that will hold a fair edge for a very long time. It also tends to "orange peel" when finished. You can't really get a full brilliant polish on it.

The creation of a blade is a balance between hardness, flexibility, and wear resistance.

The elements of the balance are 1) the design of the edge, 2) the material of construction, and 3) the heat treat of the material.

440V is a very corrosion resistant material that, when properly heat treated gives some wear improvement over 440C and even ATS-34. Most folks have never owned a knive that will take and hold the edge possible with properly HT'd ATS-34. They can get just SCARY sharp and hold the edge very, very well.

We take ATS-34 to 1950F for 15 minutes in a CaCl2/NaCl computer controlled salt pot, and quench it into a blueing salt pot at 600F for 15 minutes.

Upon cooling to room temp, the blades are cleaned and left overnight in an LN2 bath that will evaporate rising to room temp in about in time to work the next morning.

The blades are then drawn twice to 400 F in the low temp salts with a cool to room temp in between.

Every blade is tested for hardness and we almost always get RC59-60. The edge is sharpenable and yet not brittle. The edges will bend rather than break.

We get similar results with 440V, and BG42. Franklly, the additional cost of the material does not usually justify the use of BG42. 440V is a good investment for use in very corrosive environments.

If you want a heller of a sharp, long wearing knife and have the tools and patience to sharpen it ... CPM 10V and Vasco-Wear ( CPM's equivalent is CruWear) is the right stuff. These materials have to be completely worked before heat treating as they cannot be worked afterwards. They get to RC63-65 routinely.

CruWear is pretty corrosion resistant ... CPM 10V is not.

As per damascus steels and carbon steels, hardness is selected with an eye to blade and edge design and blade size. A Bowie at RC 52-55 is plenty hard, holds a good edge, and will not likely be broken in the field by an unlucky or clumsy user whose life may depend on the blade.

A real hard-core solution is heat treating to bainite ... which is a hard but VERY flexible material. A bainite blade HT'd to RC 57-59 can be bent to almost a 90 degree angle without chipping the edge!

1084/15N20 damascus at RC 59 will take an edge as sharp as ATS-34. Unfortunately, this mixture will not form bainite. Damascus can be made from L6/1084 and HT'd to bainite by a very skilled person. It is an awesome material but is not inexpensive and is not very corrosion resistant.

By the way ... for you guys that have carbon steel knives that you use and love ... the secret to lack of corrosion is keeping them clean and using a WAX to protect them. Bees Wax or Johnson's Floor wax is terrific.

Now, I am interested in Bohler K390 steel. Looks it is near wear resistance as 10V, but with higher toughness and great bendind strength. Belive that K390 is now top notch cold work steel.

PDF file : http://www.sten.fi/data/attachments/K390DE_MICROCLEAN.pdf

There are also attempts to make knives from Uddeholm Vanadis 10 steel.

PM steels by Bohler, sorry for image quality

Jiri,

Can't tell what the corrosion characteristics of the material are from the data sheets. Remember that I said CPM 10V is not good ... you can watch it rust.

That aside, one should be careful about getting too exotic into wear resistant materials for knife blades. Blades made from these materials may be effectively impossible for all but the most persistent non-professionals to sharpen.

For CruWear (which is on the very high end of tough and wear resistant) I use a series of 2x72" belts on belt grinder fitted with a 2 hp continuously variable speed motor. When I have it RAZOR sharp, then I go to stones for the final touch up. The average person is not likely to have such equipment available.

When a properly done ATS-34, 440V or BG-42 blade will field dress 5 to 10 deer without being even lightly stoned ... A blade made from a material such as you suggest reminds me a little of the need/want analysis of once published on a MacLaren F1 supercar. "Obviously, no on "needs" such a thing ... but my heart aches for it."

A comparison closer to home might be between a higher quality .458 Lott bolt rifle and a high quality .470 double rifle. Both will kill damn near anything that it is legal to hunt ... the later gets more style points.

(By the way, I also understand your interest as I have blades I made from CruWear and I own a .470 double rifle ;>

Mike, I have read somewhere that 440V is CPM S-60V, have you heard the same?......DJ

That's what I read too.

It is a very nice material if a little expensive. The first knife made from it is my own. It has field dressed, skinned, and quartered 26 deer and worked salt on a few pelts.

Still no sign of corrosion and it has not needed to be redone beyond a slight recontour of the edge from where I was chopping off the wing of a goose and hacked directly into a piece of steel shot. The impact bent over a very small section of edge (1/16"). Not bad for a full swing stupid.

Holds a great hair-popping edge!

mstarling:

K390 is not stainless in any case, but will not rust as easy as "low alloyed high carbon tool steels". My point is to use DLC coating on it. Here is company doing some new "high tech" DLC coating, which is harder and slicker than "standard" DLC. And of course, here is another company specialized for making tools such reamers, drills, cutters and they have computer controlled vacuum furnace so accurate and exact heat treating is not problem.

And of course, you or me don't really need that kind of steel but it is more about feeling "this is the best steel aviable".

Jiri