Blade Steel R/evolution?

V

Vorpal Blade

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May 26, 2005
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In recent years, many strides have been made in steel performance, especially martensitic, rust resistant steels for knife blades. IMO rust resistant cutlery grades of steel do not yet have the toughness to take the impact of heavy chopping, as in very large knives or useable swords.

Stellite Talonite and Ceramics are too brittle for high shock applications and the best Titanium is still too soft, although all four are rustproof.

But recently, a new type of 'stainless' has appeared on the scene which replaces a percentage of carbon with nitrogen thus replacing carbides with nitrides, bringing a whole new level of rust resistance. Myoto Foundry's H1 has the highest ratio of nitrogen to carbon and seems to be rustproof. Next comes X-15TN and Crucibles's S30V is also supposed to have improved rust resistance due to the presence of some nitrogen. To me, the replacement of carbides with nitrides is a very exciting and promising development.

But, so far, I have not heard of nitrogen being used in anything but high chromium steels, in order to further enhance rust resistance.

Does anyone know if experiments have been done in the tougher, low alloy steels? Is there a mechanical disadvantage
in the use of nitrogen instead of carbon? What if a high percentage of nitrogen were used in S7 shocksteel? Or some of the other low alloy steels like O-1 or 1095? Would the result be superior shock resistance and good rust resistance or, would it be a matallurgical disaster; Or even impossible to accomplish? What are the drawbacks of using nitrogen to replace carbon, if any?

What are your thoughts all you blade enthusiasts or maybe even matallurgists out there.
 
I take an unpopular view on blade steel "technology". I see most of the new super steels as a tredy money maker. Every year it seems a few new steels come out with all this hype and people gobble them up no matter the price, as long as blade magazine has a nice full page ad. Personally I like Spyderco's VG-10, Case's CV steel, 440C to a lesser extent, and some similar steels. I don't think I answered what you were asking exactly, but I felt like sharing my opinion.
 
Nitrogen does not form nitrides in stainless steel. What it does do is act like carbon. Carbon in high enough levels will search out other elements to form carbides. When carbon forms carbides in high chromium steels it lowers the available chromium, thus reducing the corrosion resistance. Nitrogen does not react with the chromium but increases the attainable hardness. It's a way to fool the steel into thinking it has higher carbon. The reason it is not done in lower alloy steels is nitrogen does not dissolve in those systems. You actually need high chromium for the nitrogen to dissolve into the steel during steelmaking.
 
The proprietary INFI alloy used by Busse Combat knives is extremely tough and uses nitrogen in the mix.
 
Talonite is not brittle. All the edge failures I've seen were rolled edges, not chipped. That being said, Talonite is NOT a good material to use for a camp style knife.

Beta-C titanium is super tough. Nick Wheeler is finishing a knife for me that was forged to shape by Ed Schempp. It is the hardest to grind metal I have ever seen, and this was before heat treating! I'm looking forward to testing the knife.

Adding nitrogen to steel to improve its toughness is not a new technology. The former Soviet Union was using steels containing nitrogen back in the 1970's. I read several papers about the steel when I worked in aerospace. I never considered the possibility of applying the technology to knives until I read about Busse's Infi Steel. Kudos to Busse for being the first to bring this technology to the knife world.

VG-10 is not a new steel. It was developed many years ago for use in Japanese grafting knives. Spyderco took a chance and used it in their production knives. It proved to be very popular.

There will always be new steels to try for knifemaking. In the next few months we will be testing 1080 with vanadium, L6 with tungsten and 440B with vanadium. These are not new steels but variations of existing steels.

I think the next big leap forward will be ceramic-metals or cermets.
 
Chuck Bybee said:
There will always be new steels to try for knifemaking. In the next few months we will be testing 1080 with vanadium, L6 with tungsten and 440B with vanadium. These are not new steels but variations of existing steels.
Click to expand...
This sounds very exciting. I sure hope you will be reporting your test results.

Chuck Bybee said:
I think the next big leap forward will be ceramic-metals or cermets.
Click to expand...
Is there anywhere that we can read up on this material?
 
I do know cermets are being on cutting tools like saw blades, lathe inserts and end mills. I don't know enough about Boker's Cera-Titan to know if it is a cermet.

In the future "cermet" will be like "steel", i.e. there will be specific grades or compositions. We will learn which compositions are like 420J2 (junk) and which are like VG-10 (very good).

Carbide Processors has good information about their cermets:
http://www.carbideprocessors.com/Saws/intro.htm

Cerbide also has interesting information:
http://www.cerbide.com/
 
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