# HAP-40 vs. ZDP-189 vs. R2 ????



## Jeff

Thoughts on theae steels for kitchen knife applications?

I am seeing HAP40 being pushed a lot recently. WOW! 66 HRC!!!!

I have 2 ZDP-189 knives and I am impressed at how the edge holds up. They say it is “chippy” and is difficult to sharpen. No chips yet, and I dont have enough experience to state an opinion on how it sharpens.

I have numerous R2 knives. IMO it is an amazing steel. it is the more forgiving of the three, sharpens well on my sharpen systems but takes a while to get there. But when sharp … WOW! 

IMHO these 3 steels are a world apart from the traditional steels. Durability and edge retention comparisons don't seem fair. Having said that, there is something special about the carbon steels. The seem “warmer” and I enjoy the old school process.

Thoughts?


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## Michi

My sharpest and best-cutting knives are carbon. The ones that hold their edge the longest are SG-2 and HAP-40. Take your pick…


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## LostHighway

Personally, I would give ZDP-189 a wide pass. Here is a technical look at ZDP-189 from Larrin Thomas.
With some qualifiers I like SGII/R2. One of my SGII knives (Shibata) feels a little too insubstantial and a touch numb on the board but has not proved fragile. The Myojin, despite only being slightly thicker, feels more robust. Relative to simpler steels it isn't exactly a joy to sharpen but it isn't incredibly difficult either. Maybe finishing on a diamond stone would give me a better edge but I don't own any yet.
I have no experience with HAP40.
My personal take is that if edge endurance is a very high priority for you skip all these steels and buy CPM MagnaCut or Z-Wear.


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## big_adventure

R2/SG2 is a good compromise in a PM stainless, I'd say. Quite hard, decent edge retention, easier to sharpen and more corrosion resistant than ZDP or HAP-40.

I've one ZDP blade (Sukenari K-tip gyuto) and I really like it. I haven't had serious chipping issues - the OOB edge was razor sharp but ever-so-slightly fragile - I got a couple of extremely tiny chips after a month or so of very regular usage (it was my most used blade for that month). I redid the edge in my own image and it's been perfect since.

I don't think there is a "wrong" choice there. ZDP objectively holds an edge longer and is somewhat more difficult to sharpen than R2/SG2. Both will hold an edge significantly longer than any low alloy "carbon" steel. Both will be somewhat more time consuming to sharpen than any low alloy "carbon" steel.

As an aside, can we stop calling them "carbon" steels? All steels are "carbon steels" - iron combined with carbon is what _makes_ steel.


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## big_adventure

LostHighway said:


> Personally, I would give ZDP-189 a wide pass. Here is a technical look at ZDP-189 from Larrin Thomas.
> With some qualifiers I like SGII/R2. One of my SGII knives (Shibata) feels a little too insubstantial and a touch numb on the board but has not proved fragile. The Myojin, despite only being slightly thicker, feels more robust. Relative to simpler steels it isn't exactly a joy to sharpen but it isn't incredibly difficult either. Maybe finishing on a diamond stone would give me a better edge but I don't own any yet.
> I have no experience with HAP40.
> My personal take is that if edge endurance is a very high priority for you skip all these steels and buy CPM MagnaCut or Z-Wear.



I love @Larrin writing and his work (I have _Knife Engineering_ sitting on the table in front of me), but it should be said that, in practical use, ZDP performs better than what Larrin's analysis might indicate. His CATRA results are quite good for the steel, and it's generally easier to sharpen than the steels with higher edge retention on his list, perhaps thanks to the low quantity of V and W carbides. While it isn't exactly "forget about it" levels of stainless, it's still stainless enough that you can leave it on the board after prepping onions and tomatoes, and not have rusting or pitting an hour later (I would never do this, I'm a clean knife obsessive, but you could - my kids have done with mine).

@Kippington made some videos a while back where he was abusing a ZDP gyuto (primarily because he'd dropped and chipped it already, and knew that he'd need to fix the problem anyway, IIRC) and it handled shockingly massive amounts of abuse without failing.


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## Benuser

I've found R2/SG-2 not that simple to deburr. Took me quite some time to find a way that worked for me.


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## big_adventure

Benuser said:


> I've found R2/SG-2 not that simple to deburr. Took me quite some time to find a way that worked for me.



It's definitely much tougher to deburr than low-alloy steels. It's a pretty damn hard PM stainless steel. That said, I have two R2/SG2 knives and I find that they deburr pretty cleanly with 4 (2 per side) alternating-side high-angle edge leading strokes, followed by 10-20 edge-leading on-apex-angle strokes, alternating every few strokes. All of those are low-pressure strokes (I'd say "of course" but perhaps someone reading this isn't aware of those techniques). Mileage may vary, but that's what works for me.


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## ModRQC

Carbon steel still applies as a general denomination; the sense not being carbon content itself, but rather purity or closeness to base alloy - carbon content being the main alloying element.


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## mpier

I know this has probably been asked many times before, and I don’t mean to high jack the thread but what is your guy’s thoughts on SLD or SKD in comparison?


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## jedy617

LostHighway said:


> Personally, I would give ZDP-189 a wide pass. Here is a technical look at ZDP-189 from Larrin Thomas.
> With some qualifiers I like SGII/R2. One of my SGII knives (Shibata) feels a little too insubstantial and a touch numb on the board but has not proved fragile. The Myojin, despite only being slightly thicker, feels more robust. Relative to simpler steels it isn't exactly a joy to sharpen but it isn't incredibly difficult either. Maybe finishing on a diamond stone would give me a better edge but I don't own any yet.
> I have no experience with HAP40.
> My personal take is that if edge endurance is a very high priority for you skip all these steels and buy CPM MagnaCut or Z-Wear.






big_adventure said:


> I love @Larrin writing and his work (I have _Knife Engineering_ sitting on the table in front of me), but it should be said that, in practical use, ZDP performs better than what Larrin's analysis might indicate. His CATRA results are quite good for the steel, and it's generally easier to sharpen than the steels with higher edge retention on his list, perhaps thanks to the low quantity of V and W carbides. While it isn't exactly "forget about it" levels of stainless, it's still stainless enough that you can leave it on the board after prepping onions and tomatoes, and not have rusting or pitting an hour later (I would never do this, I'm a clean knife obsessive, but you could - my kids have done with mine).
> 
> @Kippington made some videos a while back where he was abusing a ZDP gyuto (primarily because he'd dropped and chipped it already, and knew that he'd need to fix the problem anyway, IIRC) and it handled shockingly massive amounts of abuse without failing.


ZDP is awesome, love it in my Sukenari Gyuto. Even in Larrins latest edge retention tests it performs extremely well. I believe his main bone to pick with it is that it is advertised as stainless while not really being so (I have also left it wet for over an hour and haven't had any problems). 30% better on CATRA than SG2 and that's at 65 hrc, I know it's often run 66-67. It's just not in the same league as SG2 (Love SG2 as well, one of my favorite stainless steels and a really solid all rounder).


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## ModRQC

SKD behaves more like Carbon without the high reactivity. Won’t hold an edge nowhere close like a PM but avg better than Carbon. Gets keen.

SLD dunno. Not so interested to try.


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## jedy617

Not interested in SLD at all...just D2


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## applepieforbreakfast

jedy617 said:


> Not interested in SLD at all...just D2



ZDP-189 is just fancy D2.


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## jedy617

applepieforbreakfast said:


> ZDP-189 is just fancy D2.


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## M1k3

applepieforbreakfast said:


> ZDP-189 is just fancy D2.


ZDP-189 is just fancy cast iron.


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## jedy617

Iron is just fancy atoms


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## applepieforbreakfast

jedy617 said:


>



ZDP is just D2's bigger, harder brother.
Oversimplification incoming...

ZDP and D2 are essentially just iron, carbon and chromium
ZDP and D2 are both high carbide volume steels
Both ZDP and D2 have enough chromium to be considered "stainless", but neither really are because most of the chromium is tied up in carbides
Neither is all that tough


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## ModRQC

PM steels are superfluous in home kitchens.

And boring.

Change my mind.


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## jedy617

ModRQC said:


> PM steels are superfluous in home kitchens.
> 
> And boring.
> 
> Change my mind.


Much more exciting than carbon steels imo. People hark about how amazing so and so's white or blue heat treat...in the meantime they get half the edge retention even at their maximum, and at that maximum they aren't tough either. People also talk about how they are so buttery to sharpen...but I sharpen ZDP fine. And I do it way less often


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## jedy617

applepieforbreakfast said:


> ZDP is just D2's bigger, harder brother.
> Oversimplification incoming...
> 
> ZDP and D2 are essentially just iron, carbon and chromium
> ZDP and D2 are both high carbide volume steels
> Both ZDP and D2 have enough chromium to be considered "stainless", but neither really are because most of the chromium is tied up in carbides
> Neither is all that tough
> 
> 
> View attachment 146263


What you are missing is ZDP is powdered metallurgy, doesn't actually rust the second you look the other way like D2, and has way higher edge retention. They couldn't be more dissimilar.


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## ModRQC

jedy617 said:


> Much more exciting than carbon steels imo. People hark about how amazing so and so's white or blue heat treat...in the meantime they get half the edge retention even at their maximum, and at that maximum they aren't tough either. People also talk about how they are so buttery to sharpen...but I sharpen ZDP fine. And I do it way less often



You missed the subtext: you don’t need that much retention in a home kitchen. And when you have it it’s boring because you don’t get to sharpen it in a half a year - and that short a while when you have only 2-3 good knives to use.

If I had had PMs when I was learning to sharpen I’d still be a noob today. Or bored.

And if anyone keeps a PM for long enough if not OOTB, good luck with thinning behind the edge. But bizarelly just about every single PM hits BST before the owner has to do much of anything about it. They’re always about pristine. What a boring prospect.

Mind not changed at all.


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## jedy617

ModRQC said:


> You missed the subtext: you don’t need that much retention in a home kitchen. And when you have it it’s boring because you don’t get to sharpen it in a half a year - and that short a while when you have only 2-3 good knives to use.
> 
> If I had had PMs when I was learning to sharpen I’d still be a noob today. Or bored.
> 
> And if anyone keeps a PM for long enough if not OOTB, good luck with thinning behind the edge. But bizarelly just about every single PM hits BST before the owner has to do much of anything about it. They’re always about pristine. What a boring prospect.
> 
> Mind not changed at all.


What do you mean you don't need that much retention? It's nice to have. You can say that about anything. You don't need that much thinness behind the edge...you don't need that much toughness or sharpenability...you don't need that much stainlessness, etc etc. For me, edge retention is nice to have. I enjoy sharpening but I like cutting with my knives much more and having them stay sharp. Thinning is also a breeze with diamond stones...especially since they are all soft stainless clad usually like a lot of carbon knives.

I think having to sharpen over and over is a boring prospect.


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## Nemo

ModRQC said:


> PM steels are superfluous in home kitchens.
> 
> And boring.
> 
> Change my mind.


Depends if you can sharpen or not.


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## jedy617

Nemo said:


> Depends if you can sharpen or not.


I actually love sharpening ZDP. Found it even better than SG2 actually, chromium carbides easy to deal with on aluminum oxide stones vs vanadium heavy stuff


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## ModRQC

jedy617 said:


> What do you mean you don't need that much retention? It's nice to have. You can say that about anything. You don't need that much thinness behind the edge...you don't need that much toughness or sharpenability...you don't need that much stainlessness, etc etc. For me, edge retention is nice to have. I enjoy sharpening but I like cutting with my knives much more and having them stay sharp. Thinning is also a breeze with diamond stones...especially since they are all soft stainless clad usually like a lot of carbon knives.
> 
> I think having to sharpen over and over is a boring prospect.



It's a weird legend, that of having to sharpen again and again and again carbon steels like White. I've done six preps with Maz W#2 since I sharpened it. Most involving tomatoes since it's (was) the season, among other stuff. Just tonight I thought it could do with a touch up.

Depends if you like to sharpen or not. To me it's the climactic counterpoint to cutting 'n cooking. Both are highly therapeutic, mind soothing stamina hardening activities.

And since the 3/4 of the PMs around are SG2...  been there, been unimpressed. Loses its keenness quite quickly, for all the good it was supposed to bring to me.


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## ModRQC

Nemo said:


> Depends if you can sharpen or not.



Depends if you like it or not.


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## jedy617

Fair enough. In my collection I have both and enjoy both. Still like all my aogami (mainly 1 and super)


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## ModRQC

You're entitled to love PM steels.

I said: change my mind. Yours is fine.


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## Hz_zzzzzz

IMHO, Blue steel > 52100 >> PM = SKD/SLD. Of course they are all good and I can use them all.

In PM I prefer R2 over zdp189 because zdp189 is not really stainless. HAP40 is a reasonable choice but I felt it doesn’t get as sharp as R2 or zdp189.


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## Nemo

It should be noted that HAP40 is definitely not stainless.


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## superworrier

jedy617 said:


> What you are missing is ZDP is powdered metallurgy, doesn't actually rust the second you look the other way like D2, and has way higher edge retention. They couldn't be more dissimilar.


D2 is practically stainless. Maybe you’re thinking of something else.


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## jedy617

superworrier said:


> D2 is practically stainless. Maybe you’re thinking of something else.


It's highly dependent on the finish. In the pocket knife world it's pretty well regarded as one of the lowest grades of steel there is. I personally have had bad experiences with it. It is less stainless than even some straight up tool steels like cru wear.... for your reference: How Much More Chromium Does D2 Need to be Stainless? - Knife Steel Nerds " So the status of D2 as being the high corrosion resistance “semi-stainless” is perhaps overblown. It has about half of the chromium in solution as stainless steels and there are several other tool steel options with better corrosion resistance. "


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## Steampunk

Every steel has its place. The balance is in between strength/stability (Ability to support very thin geometries, and how close to zero the edge can get.), its edge retention (Sometimes this is hardness to resist deformation when chopping, sometimes this is acid resistance, sometimes this is wear resistance.), its failure modus (Chipping vs. folding, and how you are prepared to repair either.), and its grindability (How easy it is to shape/reshape. Part of this relates to manufacture/thinning, and how easily the steel is ground, which can be eased somewhat by san-mai/laminate construction. Part of this is due to deburring, where slower to abrade steels can actually - sometimes - be a little more controllable to deburr, providing they aren't too plastic/tough. Grindability also is a factor of the abrasives you have at hand to grind/sharpen the steel with.).

HAP-40, ZDP-189, and R2/SG2 are all in that class of 'Super Steels'. They are hard to grind (Especially using more 'primitive' abrasives. HAP-40 in particular really requires diamonds or CBN.), lose stability/integrity/toughness in epic fashion when ground to a true zero edge, and are expensive to manufacture, and even more expensive to form by the maker into complex geometries for the best cutting potential. You can get amazing edge life from such knives, but at the cost of some things that are also appreciable in kitchen knives (Thinness BTE, complex geometry, cost, and ability to be maintained with a wider variety of simpler/cheaper abrasives or sharpening tools.).

HAP-40 really needs diamonds, but out of all those listed, takes one of the most wicked edges I've seen on any steel. Providing you don't grind it to the point of edge failure, it's also fairly tough. It can't be ground quite as thin as some steels with lower carbide volumes, but it holds an edge very well, even against a moderate quantity of food acids and abusive cutting techniques/bad boards. It's a steel that - if you cannot touch-up mid stream - will get you through a crazy day, doing shady stuff. It won't be your best cutter since you can't make the geometry as extreme as some steels, but it will have your back like a Marine. You really have to have diamonds or CBN to sharpen this stuff. Maybe SiC, but it doesn't feel as sharp. AlOx is a losing game.

ZDP-189 is an interesting steel... It's got all the limitations of D2/SLD, but it's been injecting steroids. Doesn't take a real toothy edge at a given grit, hard to deburr, can't be ground real thin, isn't fully stainless (It's stainless enough, honestly, unless you truly neglect your knives.), and is a nightmare to grind/sharpen/thin. However, it has stupid crazy edge retention/stability, providing the geometries are somewhat thicker.... I'd take HAP-40 as being potentially the better cutter (You can grind it just a little bit thinner, it's a little easier to deburr, and it takes a lot toothier edge.). However, I'd maybe take ZDP-189 in terms of outright edge retention if all you have are good AlOx stones (Cerax seems to do best for me.). Even naturals can sometimes work on the stuff.

R2/SG2 is in a little lower class compared to the other two, but not in a bad way. It's not as easy to deburr as HAP-40, and isn't as tough, but is much more stainless. It can take a toothier edge than ZDP-189 (Still not as toothy as HAP-40, though.), can be ground a little thinner, and is a touch easier to deburr (It's still pretty challenging.), but doesn't last as long, and is - in a weird way - slightly less responsive to AlOx or natural stones than ZDP. Edge retention isn't in the league of the other two, but it's still higher than just about any other steel used by Japanese knife makers.

If I had to work in a commissary, soup kitchen, etc, I'd probably pick up one of the cheaper HAP-40 offerings to get me through the shift. Alternatively, a simpler/mid-hardness steel, with an F.Dick rod. Both philosophies can get you through some crazy stuff.

There are some great performing R2/SG2 offerings, like Takamura, but they're really better suited to home use IMO. They're on the ragged edge of needing diamond stones, are kind of fussy to deburr, and a little on the delicate side. 

ZDP-189 knives are a bit thin on the ground these days, but I guess if you like how SLD behaves, ZDP-189 is a sort of 'Super SLD', and worth a look. It's probably the absolute most wear-resistant steel you can buy, that you can still sharpen on some natural or AlOx stones.

That said, simpler alloys can typically be ground into thinner/more complex shapes, that can cut food with greater ease, are simpler/cheaper to manufacture/purchase, and can be maintained in less time with more primitive/cheaper/more enjoyable tools. This is often a worthy trade-off, even today, in the era of some truly incredible super steels.


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## superworrier

jedy617 said:


> It's highly dependent on the finish. In the pocket knife world it's pretty well regarded as one of the lowest grades of steel there is. I personally have had bad experiences with it. It is less stainless than even some straight up tool steels like cru wear.... for your reference: How Much More Chromium Does D2 Need to be Stainless? - Knife Steel Nerds " So the status of D2 as being the high corrosion resistance “semi-stainless” is perhaps overblown. It has about half of the chromium in solution as stainless steels and there are several other tool steel options with better corrosion resistance. "


I mean regardless of all that it’s still pretty much stainless. I regularly leave my SLD out for an hour and there’s no patina or rust at all. Granted it’s a mirror finish but I feel like “rusts the second you look away” is pure hyperbole.


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## QCDawg

Get a Kaeru stainless, then let’s chat. Whatever Maxim is calling SLD.. is wicked.


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## big_adventure

I really enjoy my Sukenari ZDP189. Specifically because it's pretty effort-free, so it's on the mag strip that kids or girlfriends can use without me having to hover over them to make sure the blade is properly treated after use. Nobody touches my Kato or my honyakis - I don't trust anyone but myself to take care of them sufficiently. Anyone can grab the AEB-L, ZDP or SG2 knives.


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## btbyrd

I know that ZDP isn't technically stainless, but I'd never know it based on my Sukenari. I've had it for three or four years, and the core steel still looks brand new.


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## Hz_zzzzzz

The Sukenari HAP40 I had was pretty much stainless during my use. I've had 2 ZDP-189 and the one I used more often did get the most of core steel discolored.


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## Luftmensch

big_adventure said:


> I really enjoy my Sukenari ZDP189. Specifically because it's pretty effort-free, so it's on the mag strip that kids or girlfriends can use without me having to hover over them to make sure the blade is properly treated after use.



Exactly this . I have a Gihei ZDP189 knives. They are nice because, for the most part, you can take the knives for granted. They are sharp when you need them and they dont rust if you look at them sideways.

ZDP189 is not god's gift to steel. But I think this whole stainless 'issue' is making a mountain out of a molehill. Im prepping food in a sterile environment and cleaning up afterward... I'm not skinning elk, in rivers of hydrogen peroxide! Maybe ZDP189 is a disappointment if you are into survival gear or scuba-diving - but that is not what KKF is about.

For the little that it is worth... the vendor who sold me my knives stressed that they were _*semi*_ stainless.... and in the several years I have had them, they have been pretty much stainless. Ironically, it was KKF that 'told' me that ZDP189 was 'stainless'.


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## TSF415

I’ve been using a sukenari Hap40 lately and it’s been great. So far pretty close to stainless. Edge holds up great on poly boards. Haven’t sharpened it yet.


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