ZDP-189 - Best blade steel

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Ken H>

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Dec 31, 2011
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Hello all, my nephew asked me about ZDP-189 blades. He saw it listed as a blade steel in Japanese kitchen knives. Looking it says it's 3% carbon, 20% Cr, Tungsten 1.5%, 1.3% Mo, and 0.1% V and they are using a Rc of 66-67. Just how good is this steel? I've read it's not available outside of Japan.

3% carbon sure seems like LOTS of carbon - I guess that makes a lot of carbides? With the CPM process it keeps the carbides small.

Thanks to all for comments and perhaps a source for the steel - bet it's expensive?

Ken H>
 
can't find a source. being Hitachi steel, they probably won't sell it in US. all we can do is sit and imagine how it might be, same story as the famous Blue and White.
 
High hardness, relatively high wear resistance, poor toughness. Corrosion resistance is harder to figure out. The Hitachi datasheet shows good corrosion resistance according to their tests, but some reports from users say that it has poor corrosion resistance. Thermodynamic calculations predict relatively low chromium in solution which also makes sense given the high hardness. http://www.discipleofdesign.com/knives/ZDP189_eng.pdf
 
I love ZDP, (ab)used the shit out of a ZDP Delica(deburred mild steel with it every now and then for example) and it holds an wicked edge forever. Imo still one of the best steels around
 
Larrin said:
High hardness, relatively high wear resistance, poor toughness. Corrosion resistance is harder to figure out. The Hitachi datasheet shows good corrosion resistance according to their tests, but some reports from users say that it has poor corrosion resistance. Thermodynamic calculations predict relatively low chromium in solution which also makes sense given the high hardness. http://www.discipleofdesign.com/knives/ZDP189_eng.pdf
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I'm sorry but I can't confirm the low toughness you're stating here. I'd say it's tougher than D2 for example.
 
SV-97 said:
I'm sorry but I can't confirm the low toughness you're stating here. I'd say it's tougher than D2 for example.
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Toughness is inversely related to carbide volume. Not sure how it could be considered “tough.” Maybe tough for what it is, like z-wear, but not tough like aeb-l, or z-finit. D2 has pretty lousy toughness, so that’s a pretty low bar.
 
Willie71 said:
Toughness is inversely related to carbide volume. Not sure how it could be considered “tough.” Maybe tough for what it is, like z-wear, but not tough like aeb-l, or z-finit. D2 has pretty lousy toughness, so that’s a pretty low bar.
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Huh, guess I'm wrong then. I always considered D2 and ZDP rather tough and stuff like S30V not tough - but I'm certainly far from calling myself a metallurgist. Maybe my definition of tough isn't correct to begin with
 
I owned a Rocketsead TEI in ZDP. I didn't do alot of cutting with it but it seemed to be an excellent performer.
I believe the hardness was about 64+
I don't have much experience beyond this.
 
Henckels had their Cermax knives made of this at RC66 and a chef brings his to me every 3- 4 months to resharpen. They take probably 5X as long to sharpen as an equally dull Swiss or German make.

Takes an obscene edge but takes work. Waterproof SiC belts run soaking wet seem to work best on it.

Jim
 
Thanks for all the comments - last night when my nephew asked me about it was the first time I'd heard of ZDP-189, so I knew where to ask. I did some google searches, and found some info, but most of it was several years old.

From what I'm reading, I think I'll stick with AEB-L.... or if I want a "super" steel I might use S35V. I've used that for a petty chef and do like it.
 
I have a 10" slicer I made in ZDP suminagashi (damascus san mai with ZDP core). It is thin, HARD, and slices like crazy. I only use it for special thin cuts, or when preparing meals with people watching. The reason I don't use it all the time is it is too sharp. It will cut a finger with merely a bump. In slicing/dicing veggies, the blade running along the guide finger will shave it down to bleeding.Catch a finger tip in slicing up chives and it will take the skin right of the tip.
I have a S35VN utility sort-o-ku (sort of a santoku) that I use for almost everything . It is .060" stock and the edge lasts very well, considering daily use. At the beginning of a meal, I give it a few strokes on my white stone paddle and it is shaving sharp.

I had a large kitchen blade I made in Cowry X many years ago. HT was tricky, and the blade was really hard to finish post HT. It was a great knife, but you can make a bunch of great knives for the $240 that piece of steel cost. I gave it away as auction donation. To steal a phrase from Mr.T - I pity the fool who has to sharpen that knife!
 
Stacy, what type of HT did you use for the ZDP blade your made? Any idea of final Rc hardness? and Where did you get the steel?

Note: I doubt seriously I'll ever be using any, just inquiring minds wish to know {g}
 
Stacy, where did you get that S35VN thin stock, and any kind of steel in that thickness for fine kitchen blades? I'm from the other side of the pond and I have a really hard time to get thinner stock than 2mm that mostly came 40mm wide. Thanks!
 
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