Charpy results for ZDP-189

Larrin said:
ATS-34 has made it in to America, but all of the knives I know of with VG-10 are made in Japan. There are many other Japanese steels that have not made it in to America. Trust me, the Japanese like to keep their steels. If you get lucky it will make it in to America, but since it looks like a low-production steel, I doubt it. Since ATS-34 was planned as a big-time steel, it is now sold in the U.S., I suspect VG-10 will be available in America too, if it isn't already. Those other companies you mentioned are making the knives in Japan, which is why they can get the steel, because they are in Japan. This means that it won't likely get to be a big time steel, especially since it is so expensive. Technically they could start making the knives in large amounts and selling them in America, but I doubt it.
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ATS-34 is the Hitachi version of 154CM, which was developed in America. Because 154CM quality declined a while back, a lot of makers switched to ATS-34 but now 154CM is the preferred steel again because Crucible cross rolls it to reduce grain orientation. VG-10 is distributed by Takefu Foundry and AFAIK VG-10 knives are all made in Japan (Spydercos, Fallknivens, etc.).

Keep in mind that HRC, Charpy, and CATRA results are only two aspects that contribute to a blade's "edgeholding." Different steels resist plastic deformation in different ways. For example, CPM-1V in thin cross sections exhibits plastic deformation at 59 RC that is more severe than S30V at the same hardness. Charpy tests measure the characteristics of thicker cross sections than knife edges, so they should not be used as the gold standard for toughness.

It's also worth mentioning that the HT schedule for a particular steel can be customized to enhance different properties. For instance, to get the most corrosion resistance out of S30V you have to sacrifice some toughness. ATS-34 has a low and high-temperature temper which is an old debate for heat treaters. Different manufacturers also don't necessarily agree on the optimal HRC of a steel, such as Chris Reeve running his S30V softer than most other makers.

Realize what you're seeing in that chart with grades for corrosion resistance, wear resistance, toughness, and hardness. It's not as simple as it looks.
 
At least someone other than me realizes that they don't let those steels out of Japan. William Henry has to buy the ZDP-189 as a "knife" they can't buy it as steel, so it has to cut out to shape while in Japan or something like that. They also have to send it back to Japan for heat treating. No wonder that steel's so expensive.
 
Larrin said:
At least someone other than me realizes that they don't let those steels out of Japan. William Henry has to buy the ZDP-189 as a "knife" they can't buy it as steel, so it has to cut out to shape while in Japan or something like that. They also have to send it back to Japan for heat treating. No wonder that steel's so expensive.
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AFAIK, they recieve the blades heat treated.
 
Steven Roos said:
AFAIK, they recieve the blades heat treated.
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Actually, no, they have to grind them to shape and everything and then send them back for heat treating, something about how they don't want people to know the heat treating information. This is all information given to me second-hand by my father (Devin Thomas), he was told by Matt Conable, the owner of William Henry Knives when he was inquiring about what he thought about the steel.
 
Larrin said:
Actually, no, they have to grind them to shape and everything and then send them back for heat treating, something about how they don't want people to know the heat treating information. This is all information given to me second-hand by my father (Devin Thomas), he was told by Matt Conable, the owner of William Henry Knives when he was inquiring about what he thought about the steel.
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Well, I'll see if I can find out from Matt tomorrow. :)
 
It seems to me that any test of durability should be done with all steels at the same hardness in order to yield a meaningful result. If the steels tested are of different hardnesses, than the test proves nothing.

I understand, there are many methods of tempering which could give different properties to the same steel while still registering the same hardness; But, at least, the different steels used for the test should be equally hard. Ideally, each alloy should also be optimally treated for its type.

Even corrosion resistance can vary at different hardnesses because of the varying amounts of carbide(s) Vs. free carbon or nitride(s) Vs. free nitrogen and the amount of alloying metals left elemental or compounded. For this reason, it is possible the corrosion test might have to be done separately from the mechanical tests at the optimal hardness recommended by the manufacturer for each steel.
 
Edgy Codger said:
It seems to me that any test of durability should be done with all steels at the same hardness in order to yield a meaningful result. If the steels tested are of different hardnesses, than the test proves nothing.

I understand, there are many methods of tempering which could give different properties to the same steel while still registering the same hardness; But, at least, the different steels used for the test should be equally hard. Ideally, each alloy should also be optimally treated for its type.
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Well, they claim ZDP-189 is best at 67RC, so you should test it as such.

No matter how you slice it, I am impressed with ZDP-189.
 
Thanx Vassili, great info. :)

Spyderco did a short pilot run of Chinooks with VG-10. We wanted to work the steel ourselves to better understand the properties.

Our production VG-10 models are made in Japan.

It is always surprizing to see argument over "what's best". I have found the approach, "all good, just different" to be more satisfying. I get to enjoy them all. ;)

Spyderco is doing a couple of short runs in ZDP-189 FRN models to provide an inexpensive opportunity for knife aficianados to experience the steel.

The Caly jr and the Delica. both will be available this year.

sal
 
Larrin said:
My point is that ZDP has pathetic toughness even compared to other stainless steels. I don't think the few knife companies using it should have it to near the hardness they are bringing it to.
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For some knives you don't need it and the extra hardness could be of benefit. What types of knives is it being used for?

SteelDriver said:
CPM-1V in thin cross sections exhibits plastic deformation at 59 RC that is more severe than S30V at the same hardness.
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A Rockwell test measures plastic deformation in a thin section depth wise. The most accurate way to HRC an edge is to grind it flat enough to allow the ball size (not very wide) and HRC it dead on.

Edgy Codger said:
It seems to me that any test of durability should be done with all steels at the same hardness ...
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Not all steels can get to the same hardness, and various steels show peak properties at different hardness levels.

-Cliff
 
I just found this article while looking @ W.H. knives.
Interesting thing is the testing results section. ZDP is compared to several high end steels, however the article never mentions how were they hardened. Apparently we have to assume D2 was "properly" hardened to 62HRC (because they mention that in the article) and others probably around that, and based on the numbers in article ZDP was 67HRC. From what I know many steels can be taken to 67HRC, inclusding M2, 1095, D2 (Neil B. mentioned few times that one), CPM-10V and so on. I wonder how would those fare compared to ZDP @ 67HRC. I think the difference would be far less dramatic compared to the article data...
Another thing is I don't quite understand how lamnating can be cheaper than using pure steel. Definitely more labor, but I might be wrong.
Although considering other data in this thread I'd think lamnatig is there to help with very low impact resistance...
 
Gator97 said:
From what I know many steels can be taken to 67HRC, inclusding M2, 1095, D2 (Neil B. mentioned few times that one), CPM-10V and so on.
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M2 maxes out at 65 HRC, 1095 at 66, 10V at 65, D2 at 62. Getting over 66 HRC requires a large secondary hardening, which drives the hardness up after the tempering, you can get up to 72 HRC that way.

I think the difference would be far less dramatic compared to the article data...
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It would be informative to know how the knives were sharpened, was the geometry the same and how was the stopping point determined. If it was cut until it feels right it is meaningless anyway.

Same with the data on toughness and chipping, I would like to know exactly what was done. Contact them (Dave/Frank) and see if you can get one for the pass around forum.

-Cliff
 
Cliff Stamp said:
It would be informative to know how the knives were sharpened, was the geometry the same and how was the stopping point determined. If it was cut until it feels right it is meaningless anyway.
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Actually you're absolutely right, somehow, I assumed those were identical blades they were testing, but thinking again, I doubt that was the case. Considering that even the same HRC doesn't mean same HT and properties...

Dunno how will the passaround stuff will work. But worth a try
 
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