Demystifying ZDP-189

DeadboxHero

DeadboxHero

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Mar 22, 2014
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Zdp-189


This is highest wear resistant steel available from Hitachi Metals Japan.

It also has some of the highest hardness and carbon content of any knife steel.

However it doesn't have the raw wear resistant power of CPM vanadium steels.

But there are some merits and drawbacks waiting to be discovered from this mysterious steel from the land of the rising sun



Spyderco is one of the few companies bringing this exotic steel to the US folding knife market and with an affordable price. :)




This steel is not new, but since it's not widely available I thought it would help to give more detailed accounts for my fellow Knife steel aficionados

What's fascinating is this is the highest carbon content available in a knife steel

With 3 times the amount of 1095 at 3.00%

This puts this in the category of a cast iron more then a usable blade steel but the Powdered Metallurgy is what makes this happen.



Here's a reference chart from bohler Metals to the PM process.

It's the powder metal process that allows more alloying then physically possible with normal ingot steels.

Each droplet becomes a "micro ingot" that allows for the even distribution of alloys and carbides.

This means we get 3% carbon, 20% chromium and 1.4 molybdenum
There is also trace amounts of a few other elements but these are the heart of this steel.



this is a chart from Gator's Zknives app (love this app)

This marriage of high levels carbon and chromium allows for high hardness not found in other steels as well as a high volume of chromium carbides that are dispersed evenly throughout the matrix thanks to the PM process.

Molybdenum, also a carbide former, helps as a boost the cutting ability

All this means is that when the edge breaks done from cutting, the harder packets of chromium carbides are exposed allowing for a really long working edge; not razor sharp but sharp enough to lacerate materials.

There is a down side, nothing is ever gain without pain

The steel has a reputation as being chippy.

It's still a usable steel for blades, it just requires more discerning use.

Light cutting, kitchen use, game processing

I've had a microchip occur when carving feathers on pine wood with the factory edge.

So Bushcraft may be out of the question untill further testing to confirm. it could just be the factory edge( btw this was the sharpest factory edge I've ever received on a knife 15dps with a 20 DPS micro, I was cleanly push cutting supported paper towels, Ooo makes me giddy:))

Also, it's not very stainless and can be quite reactive.

This can be confusing considering the %20.00 chromium

However,
Most of that chromium is locked in carbides.

Also since it's not laminated with stainless,this require extra care to maintain especially since the pivot area can rust away destroying the knife.

I'll share my rope cut testing later.




Standby as we go in depth into the characteristics of this steel and flesh out as much as we can about this curious material

Shawn.
 
You forgot to mention what a headache this stuff is to sharpen. That's the biggest con for me and the main reason I don't use it.
 
Actually I finally bought a spyderco sharpmaker.

I was very curious to see if I could recreate the trouble people have with the brown stones and this steel.

standby friend.
 
I reprofiled my Stretch ZDP189 with DMT stones and it took quite a bit longer than I expected. I would not attempt it with the brown spyderco ceramic. Touch ups, sure, but not real metal removal.
 
[YouTube]slOgleNh45A[/YouTube]


I keep forgetting to post this video here.

I do some rope cutting on 3/8 Manila to show some wear resistance.

I also share my opinions about it as well.
 
I have some William Henry B-15's with San Mai blades. The blade center is ZDP-189. The cladding is 410 Stainless which is known for its corrosion resistance. In hard use, I notice more corrosion on the bread than on the bologna. So I would rate the stainlessness of the ZDP much higher than average. I haven't had any chipping issues either in 10+ years of EDC use.

Silicon Carbide stones were developed to sharpen Tungsten Carbide tooling at 72 HRC. ZDP-189 is usually hardened to 67 HRC. Al2O3 and SiC have no problem sharpening ZDP.
 
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tiguy7 said:
I have some William Henry B-15's with San Mai blades. The blade center is ZDP-189. The cladding is 410 Stainless which is known for its corrosion resistance. In hard use, I notice more corrosion on the bread than on the bologna. So I would rate the stainlessness of the ZDP much higher than average. I haven't had any chipping issues either in 10+ years of EDC use.

Silicon Carbide stones were developed to sharpen Tungsten Carbide tooling at 72 HRC. ZDP-189 is usually hardened to 67 HRC. Al2O3 and SiC have no problem sharpening ZDP.
Click to expand...

As far as I know Tungsten carbide is extremely hard, ranking about 9 on Mohs scale which is far.......far more then 72 HRC ??
I have no idea what kind of grind stone is this one in link , but I have and use 800 and 1200 . And it sharpen HSS steel blade on 64-67 HRC in minute ...................

https://www.borideabrasives.com/PublicStore/product/AS-9,18,244.aspx
 
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The brown Spyderco sticks are hard enough to sharpen ZDP. They just aren't coarse enough to remove material fast. It's like trying to grind on a polishing belt.
The MOHS scales are not very useful for comparing similar materials. The old scale only goes from 1-10. The new scale goes from 1-15. It's like a Fahrenheit scale that goes from 0-20. Try heat treating with a short thermometer.
Tungsten Carbide at 8+ to 9 MOHS= 1400-1800 Knoop. Al203 at 9+MOHS= 2100 Knoop. Silicon Carbide at 9+MOHS= 2480 Knoop. Diamond at 10 MOHS= 7000 Knoop.
Most of the SiC wheels I have seen for sharpening Tungsten Carbide tools are green. Most of the SiC stones that I have seen for sharpening knives are gray. I don't know if the color difference is due to the abrasive, the binder, or the fusion process.
 
Per your comments"

"There is a down side, nothing is ever gain without pain

The steel has a reputation as being chippy.

It's still a usable steel for blades, it just requires more discerning use.

Light cutting, kitchen use, game processing

I've had a microchip occur when carving feathers on pine wood with the factory edge.

So Bushcraft may be out of the question untill further testing to confirm. it could just be the factory edge( btw this was the sharpest factory edge I've ever received on a knife 15dps with a 20 DPS micro, I was cleanly push cutting supported paper towels, Ooo makes me giddy)

Also, it's not very stainless and can be quite reactive.

This can be confusing considering the %20.00 chromium

However,
Most of that chromium is locked in carbides.

Also since it's not laminated with stainless,this require extra care to maintain especially since the pivot area can rust away destroying the knife."

I've got W&H ZDP blade clad with stainless in a Tom Brown Tracker folder. I use it for anything and everything. I've cut the backs out of chickens, used it with acidic foods, opened boxes, etc. It has never chipped and never had a problem with corrosion of any kind. When I use it with acidic food, I just rinse it off when convenient. When it gets really gross (e.g. chicken processing) I wash it in hot soapy water and dry with a paper towel. I've had no stains, pits or corrosion. I have yet to need to oil it, but have once.

The neatest thing is that it really hasn't needed to be sharpened, but I've run it across the Sharpmaker at 30 degrees a few times just for fun.

No microchips at all...No rust either.
 
brownshoe said:
Per your comments"

"There is a down side, nothing is ever gain without pain

The steel has a reputation as being chippy.

It's still a usable steel for blades, it just requires more discerning use.

Light cutting, kitchen use, game processing

I've had a microchip occur when carving feathers on pine wood with the factory edge.

So Bushcraft may be out of the question untill further testing to confirm. it could just be the factory edge( btw this was the sharpest factory edge I've ever received on a knife 15dps with a 20 DPS micro, I was cleanly push cutting supported paper towels, Ooo makes me giddy)

Also, it's not very stainless and can be quite reactive.

This can be confusing considering the %20.00 chromium

However,
Most of that chromium is locked in carbides.

Also since it's not laminated with stainless,this require extra care to maintain especially since the pivot area can rust away destroying the knife."

I've got W&H ZDP blade clad with stainless in a Tom Brown Tracker folder. I use it for anything and everything. I've cut the backs out of chickens, used it with acidic foods, opened boxes, etc. It has never chipped and never had a problem with corrosion of any kind. When I use it with acidic food, I just rinse it off when convenient. When it gets really gross (e.g. chicken processing) I wash it in hot soapy water and dry with a paper towel. I've had no stains, pits or corrosion. I have yet to need to oil it, but have once.

The neatest thing is that it really hasn't needed to be sharpened, but I've run it across the Sharpmaker at 30 degrees a few times just for fun.

No microchips at all...No rust either.
Click to expand...

Schweet. Any pictures?
 
I am not picture enabled :). It's a plain jane, Ti-handle, button lock, thin blade in their pointy style. It has sold me on W&H ZDP. They don't divulge much info about it, such as hardness. I believe W&H makes the only ZDP american made knives outside of Kai/Kershaw made knives, such as AGRussell's Aries.
 
My experience with this steel pretty much mirrors brownshoe, with one exception. My ZDP knives do tend to stain (which I like), but it's a light staining. I'll try to see if I have some pics, but I do remember some light polishing on the blade which returned it to a kind of glossy finish with no stain, greatly annoying me. I really like for my knives to show their usage...
 
Sodak and browshoe got me thinking



Now I'm insanely curious and willing to share with you all.


Time for further review

I've been EDC ing this blade for a few weeks.

Mostly utility cutting. Food and packages some cordage.
Hahaha I even dropped it on the tip on asphalt! Yikes

It didn't shatter into a million pieces either just a dentin the tip that will come out naturally in a few months of using and sharpening


I've also used it to clear some bramble Bushes and left the green plant gunk on the blade. Slight discolored the blade but wiped off with no patina or rust. Unlike my Gayle Bradley in M4 that would patina instantly if not wiped in seconds.

Sharpened the edge freehand on a DC4 while I was at work then I hit it on a 3k and 8k a few days before testing.




No chips or dings, sharpened at the 15dps but the microbevel is still present just microconvexed it. The micro is under 20 fully apexed and polished from edge trailing passes.
If I wanted HHT 4 I'd have to do a 15dps zero with no micro.

But that's for another update and will be explained later if confusing.


Here's our first subject a finger thick piece of pinewood with Bark.




I didn't cut it gingerly. I went ape on that wood.
Shredded it.




Time to check the edge.











Nothing, no damage, just debris


Huh? last time I had damage from doing something less forceful on pine. Must have been some burning on the factory edge.





No mercy. It's time for carving this old weathered hickory axe handle.

Brutal stuff. Very hard. Not easy to carve.



Again, full strength cuts I'm not holding back



Still sharp enough for some hickory feathers



Shredded the handle, used full strength and speed.



Hahaha OMG the blade feels hot from the cutting!


Was cutting big chunks like this every cut.



Made some cuts on paper a few snags. Most have damage but not visible to the eye and still cuts good.



Still shaving sharp doesn't need to scrape catch's hair on skin and pops em

Again no damage.




Huh?


Alright time to punish ZDP189 to the breaking point.

I have to know what the limits are.


Time to deburrs and shave a piece of steel!:eek:



Spheroidized annealed 80crv2 to be exact.

Cut off all the Burrs, then I tried to "feather" steel.



Not quite feathersticking. I'm not well practiced at making metal ones :D

I then tried to lightly baton the steel with some light taps from the axe handle.



Left a mark.

Time to check the edge.

Wow, actually not that bad.

Visable damage with a larger more noticeable chip but very small considering my expections and the abusive cutting.


From the batoning, deforming near the heel.




Here's a better close up of the damage




Here's how well is cuts.



Made a raggedy cut in paper but still did it.







Hahaha time for sharpening blasphemy.




I'm going to use this cheapo soft Arkansas stone to restore the edge.

Whaaa?!
:eek:


Here is the bevel after 20-30 alternating passes on the stone.



Most of the damage seems to have been burnished back in place.

Of course the single chip remains. Very small though, can you see it?

Here's the cutting.



Gross.

Let's do it again, but this time, I increased pressure with edge leading strokes each side 20-30 times. I reduce pressure with each stroke Frome 3lbs to the weight of the knife.




Cut cleaner but still some raw damage tearing the paper.


Back to the stone!

This time a rapid Japanese style scrubbing stroke

I didn't make a burr, I just did it until the damage was realigned I then finished with stroping passes on the stone.



The edge looks good feels sharp.

Time to test.




Acceptable

This edge looks good too



Haha cool shaves again too



Conclusion on testing.





Aftermath


Close up on edge




Well, I guess it's not that chippy with the factory edge sharpened and used on proper cutting mediums

Now I know. Cool

Also, you can keep it sharp with crap abrasives. It's all in the hands that craft the edge.

I'll share more later

Hopefully ZDP189 is becoming less mysterious for you bros out there that want to know what it's like in use.

Take care

Shawn

 
Nice work! Appreciate all the effort you took.... the Endura in flat ground ZDP-189 is a real 'sleeper'.
 
Buffalohump said:
Nice work! Appreciate all the effort you took.... the Endura in flat ground ZDP-189 is a real 'sleeper'.
Click to expand...
Thanks brother. Its amazing how affordable these spydercos are with zdp189. especially compared to kitchen knives in zdp
Chris "Anagarika";16152016 said:
Shawn,

Nice test and thanks for sharing!
Click to expand...

Thanks Chris :)
 
DeadboxHero said:
[YouTube]slOgleNh45A[/YouTube]


I keep forgetting to post this video here.

I do some rope cutting on 3/8 Manila to show some wear resistance.

I also share my opinions about it as well.
Click to expand...

I don't get it , few cut in wood and little manila and end of the story of ZDP189 , no cut paper ? And definitely you need to purchase protective gloves, you cut yourself again :thumbup:

See what can 52100 ................little long video but worth a look

[video=youtube;vjhbSyFAI_U]https://www.youtube.com/watch?v=vjhbSyFAI_U[/video]
 
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