Question about steels

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L2bravo

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Jun 14, 2013
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I got a Stretch in ZDP-189. I was sharpening it, and there is a real difference in this. It wasn't a problem with my DMT's, but you could tell it is some tough stuff.

Correct me if I am wrong, but ZDP is a very very fine grain steel, is it not? I understand that they RC it around 67, but what does that mean in the bigger scheme of things? How would it compare to say, Cruwear? I realize CW is a high wear steel, but is ZDP? I would love to have some clarification on this. Thanks for the help.
 
High wear? Yes. High toughness? No. I have limited experience with ZDP but I like it. It gets super sharp and holds that edge for what seems like forever.
 
LOL, I was just joking friend. I like the ZDP, and yes, it is really hard! What I fail to understand, is when you take something like ZDP and compare it to K390, or Cruwear. I realize that those are "high wear" steels, but what does that mean in practice? Does this make any sense?
 
I'm no expert in steel, but as I understand, I has to do with overall carbide content. Higher carbide steels will have higher wear resistance than lower carbide steels.
 
ZDP has a very high Chromium content which contributes to the formation of Chromium carbides, this combined with high hardness gives it a high level of wear resistance. I have not used CW so I cannot comment on that. Compared to a steel with a high volume of vanadium carbides such as S90V its not far off, the difference will come in how the edge degraded in use. Steels with vanadium carbides retain a duller "working edge" and steels with Chromium carbides retain sharpness but once dull they are dull.
 
I believe Spyderco started running their ZDP-189 around 63 RC after people had chipping problems. I don't have any personal experience with the steel. so I can't add anything else...:)
 
9blades said:
I believe Spyderco started running their ZDP-189 around 63 RC after people had chipping problems. I don't have any personal experience with the steel. so I can't add anything else...:)
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This is my understanding as well, when they first started producing ZDP blades they targeted 65HRC (and were usually at or above target) but when they started to hear complaints of chipping from the average user (that wasnt crazy like we are) they dialed it back to the 62-63 range on current production blades.

AFAIK 67-68 is the max achievable HRC ZDP-189 can be treated to and I only know of one maker that goes to full hardness.

What angle are you sharpening at? I sharpen my ZDP Dfly at 12DPS because I don't really use it for much so it's more for fun, hanging hair, no problem, if your feeling really brave you can slash hairs off your arm in a quick [controlled] swiping motion without ever making contact with skin but I wouldn't use it to cut anything more than paper/hair/string/thin plastics for fear of chipping.
 
I just sharpened a FFG ZDP endura yesterday and was rather disappointed. My dad has a older saber ground endura and the difference in hardness was very obvious. still sharpened nicely but lacked some sharpness due to hardness.
 
I am not good with sharpening yet, so I'm also not keen on working a ZDP edge back to life.

Two days ago I finally took my CF Stretch in to Plaza Cutlery for a sharpening. When I scored it off the bay place, the seller claimed only carried once or twice but I found rust inside the liners as well as gimping and thumb hole-- not to mention the the edge was clearly not up to par. Used once or twice yeah right.

Anyhow, after hitting the edge with a straightener a few times and testing it on paper, Russ was not pleased and took it to the back. A bunch of "noise" and while later, he came back out and said, "I misheard you when you said ZDP," as he handed it back. Hahaha.

This thing is screaming sharp now!
 
Hi L2Bravo,

Many foundries will produce a "jump higher-run faster" exotic blade steel as a car company might offer an exotic racing model model. Hitachi makes ZDP-189. Really special stuff for edge retention. I personally carry ZDp quite a bit.

sal
 
Sal, thanks for your input. That's exactly why I am mid stroke of completely divesting myself of brand X right now. And going all Spydies.

Could you please tell me a little more? Particularly how ZDP differs/compares to some of the other high end steels? I don't own a CW, (but am trying), but I compared it to something like that. Thanks again for your input.
 
ZDP compared to steels like S90V, CTS 204P, M390? It will have slight performance differences from all of these, Ankerson would be a good person to ask: http://www.bladeforums.com/forums/s...based-on-Edge-Retention-cutting-5-8-quot-rope Through my own research and limited personal use, I've decided that its a very cool steel that just seems to cut indefinitely. If you like your EDC to have a very very sharp edge and retain that extremely sharp feel, instead of loosing initial sharpness and getting a "working edge" after use, this is your steel. I think that the fine grain structure coupled with very high hardness are why, and you can take it to very shallow edges without fear of rolling or chipping especially when you compare it to other high-carbide stainless steels. It's exclusive and very impressive.
 
L2bravo said:
Sal, thanks for your input. That's exactly why I am mid stroke of completely divesting myself of brand X right now. And going all Spydies.

Could you please tell me a little more? Particularly how ZDP differs/compares to some of the other high end steels? I don't own a CW, (but am trying), but I compared it to something like that. Thanks again for your input.
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That's really going to depend on what you are looking for, and what you are going to use the knife for and how.

ZDP is a cutlery steel by design and developed to work at high hardness ranges from 62-68 HRC.

As others pointed out it's mostly chromium carbide so it will be somewhat different in how it performs compared to the other high end steels.

The other High End, high carbide steels are tool steels for the most part and except for a few like S110V, K294 (10V) they are ment to to work in the 58-61 HRC range.

What that means is they have a lower compression strength due to the lower hardness range so the edges will deform somewhat easier than the steels that operate in the higher HRC ranges. But that's a double edge sword as the steels that work in the higher HRC ranges can chip out easier. It's a fine line really and a balance has to be made between performance and toughness to bring it all together in a blade that can be used.

Now a lot of that can and is adjusted with blade grinds, thickness behind the edge and edge geometry to help make the edge more stable or make it slice better depending on the intended use of the design.

A knife isn't much use if the edge falls apart or rolls with the slightest use.
 
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