Cowry-X

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Gabe Newell

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I purchased a 7" Hattori Santoku:

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The description of the blade was " Kauri X stainless steel surrounded by Damascus steel forged from stainless steels and pure nickel." I've also seen it as Kawri X.

bgknife1418alt2.jpg


The steel appears to be from Daido Steel in Japan (Daido Steel, Tokyo Japan). I've seen Cowry-X listed as RT-6 and Cowry-Y as CP-4.

Here's another picture of a close-up of a Hattori bowie:

hatstag3.jpg


another Hattori Damascus Cowry-X knife:

Hana.jpg


where the blade is described as "Cowry-X Nickel stainless Damascus steel - the core cutting edge is the Cowry-X sandwiched with 60 layered 420J1 and Nickel Damascus steels. Cowry-X is a newly developed powdered metal alloy of 2.0% chrome and 3.0% carbon that can be hardened to HRC 65-68."

and another:

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Glenn Waters (www.glennwaters.com) also uses Cowry-X, which he describes as "Very similar to the above ZDP-189 in that its hardness is RC67 and takes a great mirror polish but a foggy mirror polish, A great blade steel but expensive. Produced through gas atomizing, Hot Isostatic Pressing (HIP) which is very abrasive resistant."

For comparison, Glenn's description of ZDP-189 is "ZDP-189 Hi tech stainless made by Hitachi maintains balance between its high hardness of RC 67 and its ductility. It was developed solely for the purpose of knives. It is a powdered metal, and has 3% carbon, which gives it a very high hardness and yet still remains ductile. A great knife steel but expensive. Its high hardness and strength make it great steel for working knives because It can cut through dried bamboo without marking or scratching the blade. Is recommended for heavy work like chopping and for art knives because it takes one of the best mirror polishes you can get, providing you finish it to #2,000 grit before professional air free heat treating. Has been used in Japan since around 1995. Some time in 2000 Hitachi will release a sanmai (sandwich) with ZDP-189 in the middle with ATS-55 on the outside."

On Spyderco's steel table they list ZDP-189 as having 3% carbon and 20% chromium, which makes me think the 2% listed above for "chrome" was inaccurate.

The one example I could find of Glenn using Cowry-X was this folder with the blade harened to RC 67:

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If ZDP-189 and Cowry-X are basically the same steel, here's a translation from Japanese of some relevant heat treating information:

ZDP-189 Information

Koji Hara makes a ton of Cowry-Y knives, for example:

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I'm going to assume, though, that Cowry-Y has nothing to do with Cowry-X other than being branded similarly by the company that makes it.

I am curious if people have any experience with this steel, and if ZDP-189 and Cowry-X are one and the same?
 
I can't seem to find any other steel with a carbon content this high. Is this only possible with powdered steels?
 
Here's an excerpt from another thread on BladeForum by Jin:

"[t]he Japanese has already developed a new generation of ATS-34 {NO! I am not talking about ATS-55...}, known as ZDP189... supposingly this steel can easily reach the hardness of 70Rc!! Why don't we see any knife made from it, nor even have we heard about it? The truth is, it costs a bomb!! The material itself is more expensive than most production knife we can find in the market!! As I understand, there is only one Japanese knife company produces a ATS / ZDP "San Mai" knife from it, and I don't find the price tag attractive at all...)"


What steel is the mystery knife?
 
Anecdotally Murray Carter used ZDP in kitchen knives, although I can't find any examples of that anywhere online.
 
And here's an excerpt from WrongFriend editted slightly for readability and to update the hyperlinks:

"Cowry X and Cowry Y are made by Daido Tokushu Ko . Cowry X is high carbon steel, and Cowry Y is semi-stainless steel. Both are manufactured by powder metallurgical process. Cowry X hardens up to HRC67, Cowry Y to HRC63. X has more tendency to rust than Y.

ZDP-189 came from Hitachi. The name was their project codename. ZDP contains 3% carbon with 20% Chrome combined by their own powder manufacturing process. If adequately heat treated, it is around HRC65. Hatta heat treating gave an idea of laminating it by ATS-34 for toughness. In this case it can be hardened up to HRC68. The laminated steel was made into a knife shown at the 1999 Atlanta blade show. They claim the knife made from the steel doesn't chip, bend after any hard use... albeit some of my friends report their knives chipping.

Cowry X and Y have fairly good grind-ability, compared to ZDP189 that is almost impossible to grind.

I have no more specific data about these three. If you're interested in Cowry X and Y, try Daido English Language Site.

If you're interested in ZDP189, try Hitachi Metals English Site."

The original thread this is excerpted from is New Japanese Steels
 
Dang-it You guys! Stop, my head hurts! I havent gotten the old Japanese steels and methods figured out yet.
 
Bruce, you seem to have a lot of interesting damascus patterns in the knives on your site, e.g.

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and

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I saw the pictures with the billet of powdered steel mosaic Damascus. As well as your bio:

"The majority of the blades I make now are high carbon steel damascus in several of my own patterns and styles. Two or more carbon steels are heated to 2300 degrees and forge welded together by a hydraulic press of my own design. The press allows very good control on the hot steel for stretching and patterning for consistant flawless damascus blades. The forge is a factory made 3 burner forced air and propane model fitted with a thermocouple and a digital pyrometer. I am able to adjust the fire to achieve a stable high temperature for welding or a lower temp for forging a blade to shape."

Would you be interested in trying a Cowry-X Damascus project?
 
Gaben, Hey I thought those patterns looked familiar, those are my knives. Thanks for posting them. What kind of project do you have in mind? The new Japanese steels that you are talking about sound interesting but I know nothing about them. Are you a forger? Do these steels weld like most others? How can they get the high hardness and still be tough not brittle. A metal file is only 63-65 rockwell but will snap like a pretzel.
 
Gabe...

As you've found out ZDP-189 and Cowry X are two different steels. Murray Carter uses a variant called ZDP-247, which he says is designed for forging.
 
They will not export zdp 189 correct? and it seems Cowry X gets harder, from what i read above. Would that not be preferred?
 
Not a bad thread, and not so long it hurts to read.

But grindemup, you can search and learn, and ask questions, without resurrecting a thread with information that may be out of date. A simple link to the older thread in your new original post would do the job.
 
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