S110V or ZDP-189

Y

yultuz

Joined
Dec 4, 2008
Messages
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Hi,
I'm interested in Rockwell Hardness rather than shape of knife. As far as I researched, Kershaw Shallot ZDP has 64-67 HRc while S110V has 60-62. However in some sites, S110V versions are more expensive.
In this forum these steels have been compared, but according to their shapes (weight, thickness of blade etc...). Which of them is better for edge retention, HRc, rust resistance. As far as I learned, HRc is reverse proportional to toughness, why? Edge retention is better in high HRc or high toughness?
If you inform me about these subjects, I'll be very glad.
Thank you. Kind Regards,

Tugrul
 
Toughness and hardness both have to do with the way you adjust the microstructure of the steel during heat treat. Any given steel type has a specific hardness where the structure is at it's stiffest, but also most brittle. If you do a good job this is what you have after quenching the steel. After the quench you temper it, what this does is it relaxes the structure, but doesn't degrade it to the point of destroying the structure formed during heat treat. Steel that has been properly heat treated can be both tougher and harder than poorly heat treated, or untreated steel.
Once you assume proper heat treat however, if you have two blades of the same steel type made by the same people, if one is a few Rc points softer, it can usually be assumed it will be tougher, as the microstructure will be more relaxed.
Really there are lots of variables, but that's the basics of hardness vs toughness.

If you're going to compare S110V and ZDP-189, then most of the advantage goes to S110V. It is both more wear resistant, and significantly more rust resistant, as ZDP-189 has been found to be a little less stain resistant than most stainless steel types.
While ZDP-189 doesn't have all the fancy carbides that S110V does, there are some applications where higher hardness is more important, but usually you have to be very picky to tell the difference. ZDP-189 will be better at taking a thin edge, and should be easier to sharpen. S110V will usually hold an edge longer as well as being more rust resistant.

Oh, and welcome to the Forum. This is a great place for inquiring minds.
 
Dear Jashua J.,
Thank you so much for your great information.
Does high HRc not mean high edge retention?
Although ZDP-189 has 20% Chromium, why is it less rust resistant?
S125V is hard to process. Do you have any information that Kershaw will use it? I think S125V can beat even ZDP-189 because S125V has high Vanadium content (12.5%) while ZDP-189 has 0.1%.
Yes, here is very great place:) I visit here many times per day.
Best Regards,
 
And "edge holding" means to keep edge sharp for a long time without getting dull? or means to be sharpened easily?
 
'Generally' higher hardness, in the same steel, will give you greater edge retention.

I say generally because there are a ton of qualifiers. If the edge is too hard compared to the substance being cut it, can get micro fractures at the very edge, lessening its retention. The 'optimal' hardness for edge retention depends, not only on what steel, but on what you are cutting with it. A higher hardness in say, 1095, will have greater edge retention but would not be so good at chopping, or cutting bone, and would be a decided disadvantage if you were using the knife for digging a fire pit.

For slicing paper, opening envelopes, cutting up boxes etc. the higher hardness will be of advantage. If you are doing wood carving or using it for camping chores you 'might' discover that a certain steel is too hard (lol, this also would depend on knots and the kind of wood). Another factor is the corrosion resistance. If you are cutting wet carpet a higher the corrosion resistance may be more of a deciding factor then hardness. Same thing would apply to cutting citrus fruits or anything chemically basic or acidic. It depends on the steel and on the substance being cut. At least this is my understanding.

As for the ZDP-189 Shallot, it is very thin which would, along with its extreme hardness, make it 'more likely' to have edge retention issues in the 'wrong' substances. With anything but the 'wrong substance' it will be a wicked slicer.

Sorry for the obtuseness of this answer but, as far as I know, there is no really direct answer that can really be given.

Ladies and Gents, please correct any statements I have wrong.
 
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As for 'toughness' it might be helpful to think of a knife blade being made of clay or glue. If the glue or clay is soft it can be hit will hammers etc. and not break. As the clay dries it become harder to remold, it has lost some toughness. When it completely dries it will not be able to be remolded and will shatter if you try.

The same steel at a softer hardness will generally be tougher. Making the blade thicker usually also makes it tougher. Some blades, such as the the composite Shallot, have what can be called differential heat treatment. The spine of the blade is softer so the overall blade is tougher and can absorb more impact etc. but the edge is higher hardness for greater edge retention.
 
Thank you so much iamtoast. What I'm looking for is both edge retention (not to be dull in short time) and rust resistance. So if you compare ZDP-189 to S110V, which do you prefer?
 
I have both but have not yet used either (forming a collection of Shallots). From what others have said the s110v looks to be the better for rust/corrosion resistance and should be at least comparable to zdp-189 for edge retention. Joshua's post above suggests the s110v would win out in edge retention also.
 
I don't understand why ZDP-189 is still less rust-resistant although it has 20% Chromium.
 
The composition of S110V:
Carbon 2.8%, Chromium 14%, Vanadium 9%, Molybdenum 3.5%, Cobalt 2%, Niobium 3.5%.
The composition of S125V:
Carbon 3.3%, Chromium 14.5%, Vanadium 12.5%, Molybdenum 2.5%.
The composition of ZDP-189 according to a source:
Carbon 3%, Chromium 20%, Vanadium 0.1%, Molybdenum 1.3%.

ZDP-189 has less Vanadium, however, this only affects its edge holding capability. Because its Carbon and HRC are high, its edge holding capability should already be high. S110V hes less Chromium than ZDP-189. So why the rust/stain/wear/corrosion resistance of S110V is higher than that of ZDP-189?
 
You get "stainless" steel when you put "too much" Chromium in your steel (13%+). The reason for this is that the iron particles in steel have a certain capacity for absorbing other elements. You can have carbon steel with quite a bit of Chromium in it, but all the Chromium is trapped in the Iron particles, and doesn't stop Oxygen from stealing the Carbon out of your Iron. When you over-saturate the Iron with Chromium then you have free Chromium between Iron particles, and that's what stops Oxygen from coming and stealing Carbon.

While I don't entirely understand the reasoning behind ZDP-189 being less rust resistant than other steel types, I'm pretty sure it has to do with the 3% Carbon content, and that it's a powder metal (you can't get 3% Carbon without powder metallurgy anyway). I think it has something to do with the excessive amount of Carbon trapping the Chromium, and stopping it from being "free" to prevent rust.
Whatever the reason, I can attest to the result. My ZDP-189 Endura has developed quite a patina over the past few years.

S110V should have better rust resistance because it was partially developed with that in mind. S110V is pretty much S90V with a few modifications. One of those changes is the addition of Niobium (about 3.5%). With the addition of this element, it helps "fill" the Iron before it has the chance to absorb too much of the Chromium. So even with less Chromium overall, it has more "free" Chromium to resist rust. There are other reasons for the Niobium but that's one of them.
 
Knives are getting so good these days! I remember when makers bragged that their knives were 440C.
 
yultuz said:
Hi,
I'm interested in Rockwell Hardness rather than shape of knife. As far as I researched, Kershaw Shallot ZDP has 64-67 HRc while S110V has 60-62. However in some sites, S110V versions are more expensive.
In this forum these steels have been compared, but according to their shapes (weight, thickness of blade etc...). Which of them is better for edge retention, HRc, rust resistance. As far as I learned, HRc is reverse proportional to toughness, why? Edge retention is better in high HRc or high toughness?
If you inform me about these subjects, I'll be very glad.
Thank you. Kind Regards,

Tugrul
Click to expand...

ZDP189 is current Japanese super steel from Hitachi
CPM S110V is current American super steel from Crucible Metals

ZDP 189 is better so far for hair whittling edges (if you are able to sharpen it this way). However we have only one only first CPM S110V knife and it may not be yet established as good as ZDP189V - it is first time ever in production - HT may be refined in time. For medium sharpness it may be way better due to exotic elements presented in enormous amount in composition - Niobium (no other knife steel has it) and Cobalt, which make it super wear resistant (and hard to sharpen to hair whittling state).

I recommend you to get both for different use.

I hope Kershaw will make JYDII or Cyclone with this steel (or even ZT302).

Thanks, Vassili.
 
And since there are only 2 variations of the Shallot with S110V, you'd better snap one up.
About 600 Plain Edge and 350 Part Serr. made, they won't last long.
I bought quite a few off the bat (picture taken) then I found room to get
6 more of them from my Bro (2bkc). :D

First batch.
1840110VFAMILY.jpg


mike
 
2brothers said:
And since there are only 2 variations of the Shallot with S110V, you'd better snap one up.
About 600 Plain Edge and 350 Part Serr. made, they won't last long.
I bought quite a few off the bat (picture taken) then I found room to get
6 more of them from my Bro (2bkc). :D

First batch.
1840110VFAMILY.jpg


mike
Click to expand...


Showoff!


:D
 
I bought three Shallot ZDP-189. I'll buy five more. But I couldn't decide which steel to buy. S110V has 58-61 HRC. BG-42, S30V, VG-10 have also similar HRC. Therefore S110V has no exceptional meaning for me. With 64-67 HRC, ZDP-189 attracts my attention. I wish it had have better rust resistance... Does S110V have better edge retention than VG-10 or BG-42?
 
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