ZDP-189 steel
ZDP-189 is a powder metallurgy stainless steel from Hitachi Metals. It rates 9/10 for edge retention, 2/10 for toughness and 5/10 for corrosion resistance, and is usually hardened to 64–67 HRC.
At a glance
- Type
- Powder metallurgy stainless steels
- Hardness
- 64–67 HRC
- Maker
- Hitachi Metals (Proterial) (Japan)
- Process
- PM
- Price tier
- Ultra-premium
- Used by
- Spyderco (Endura/Delica ZDP sprints, Caly 3), Rockstead, William Henry, Kershaw (Shallot ZDP)
- Also called
- ZDP189
Composition
| Element | Weight % |
|---|---|
| Carbon (C) | 3 |
| Chromium (Cr) | 20 |
| Vanadium (V) | 0.1 |
| Molybdenum (Mo) | 1.4 |
| Tungsten (W) | 0.6 |
| Manganese (Mn) | 0.5 |
| Silicon (Si) | 0.35 |
Source: manufacturer datasheet. Nominal values; where a range is published, the midpoint is shown. Phosphorus and sulfur, where listed, are maximums.
What makes ZDP-189 behave the way it does
ZDP-189 contains 3% carbon, a high level that supports high hardness and a large volume of hard carbides; 20% chromium for corrosion resistance.
A small vanadium addition (0.1%) mainly refines grain size; molybdenum (1.4%) improves hardenability and pitting resistance.
It is made by powder metallurgy: the alloy is atomised into fine powder and consolidated, which keeps the carbides small and evenly spread. That is what lets a highly alloyed steel stay tough enough for a knife blade.
Most Cr tied up in carbides, so only moderately stainless despite 20% Cr. Usually laminated.
Equivalent and similar steels
- ZDP-189 class (similar class; compositions differ): ZDP-189, Cowry-X
Knives in ZDP-189
| Knife | Brand | Blade | Weight | Lock | List price | Buy |
|---|---|---|---|---|---|---|
| Rockstead Higo II TI-ZDP | Rockstead | 3.5" | 4.9 oz | Titanium frame lock | — | Blade HQ |
| Rockstead Sai-ZDP | Rockstead | 3.15" | 5.1 oz | Liner lock | — | Blade HQ |
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How to sharpen ZDP-189
ZDP-189 is slow to sharpen (2/10). Its large volume of hard carbides makes conventional stones slow going; diamond plates cut it much faster. Once sharp, it needs touch-ups less often.
Compare ZDP-189 with
FAQ
Is ZDP-189 a good knife steel?
ZDP-189 is strongest in edge retention (9/10) and weakest in ease of sharpening (2/10). Its average across the four ratings is 4.5/10, and it sits in the ultra-premium price tier.
Does ZDP-189 rust?
It can. ZDP-189 rates 5/10: stain-resistant rather than rust-proof, so it can spot if left wet or salty.
Is ZDP-189 hard to sharpen?
ZDP-189 is slow to sharpen (2/10). Its large volume of hard carbides makes conventional stones slow going; diamond plates cut it much faster. Once sharp, it needs touch-ups less often.
What hardness is ZDP-189?
Knives in ZDP-189 are usually hardened to 64–67 HRC. Makers can run it outside that range; harder means better edge retention but lower toughness.