20 CV / M390 VS ZDP-189

[Loudenboomer]

20 CV / M390 VS ZDP-189
I've been happy with the performance of my M390 knives. Haven't tried ZDP-189 as of yet but am interested in a stretch with this steel. I'd be interested in info from hands on field performance between the 2 steels. ZDP-189 has gotten a rap for being a little more chippy. I'd imagine because it contains less Vanadium? Edge retention about the same?

[awa54]

As used in Spyderco blades ZDP is harder and seems to retain a polished edge a bit longer, thought they both take excellent polished edges. For ease of sharpening and corrosion resistance I like M390 family steels better.

Strictly my opinion.

[vivi]

Both take a nice edge for me. M390 has an edge in corrosion resistance as awa54 noted, but they're both nice stainless steels.

Based on my unscientific layman knowledge, M390 seems to obtain its wear resistance from Vanadium carbides, while ZDP189 gets it more from massive amounts of carbon and a very high rockwell hardness.

What that means in my experience is M390 is better at holding a toothy edge and slicing abrasive materials, while ZDP189 will do better than M390 with a polished edge.

That isn't to say you couldn't polish up M390 and run ZDP189 toothy, just that in my eyes that is how you'd play to the strengths of each steel.

They both exhibit top of the line edge holding for a small folding knife, neither should disappoint.

I find M390 a bit easier to sharpen, but neither steel challenges me in that respect. You'll definitely want diamonds for either steel if you plan to reprofile them.

Neither steel chipped out on me, even running thin edges on them.

[ferider]

ZDP189 is _a_lot_ harder than M390. I'm guessing HRC 65 vs 61 for Spyderco (looking at Ankerson results, among others).

Meaning you can scratch an M390 blade with a ZDP189 one.

It's supposed to be less rust resistant, but I have yet to see corrosion on my ZDP stretch used in the kitchen.

[Baron Mind]

I value ZDP-189 a lot more than m390 right now. A) it's much more rare. There are only 2 companies producing knives in ZDP. 1 is Spyderco, the other cost about $1000 each. B) ZDP has a much higher Rockwell hardness, meaning it will retain its ultra high levels of sharpness longer, an attribute at the top of my list. M390 is more corrosion resistant, but ZDP-189 isn't a total rust bucket or anything.

[TomAiello]

Both are very good.

ZDP will hold it's edge a lot longer. M390 (et al) is tougher and more stain resistant.

Honestly, I think that the ZDP chipping is overblown. I pretty much only use it on precise cutting tools (so perhaps my sample is skewed) but it's never been an issue for me. Maybe if you are using an Endura that you use for harder chopping tasks?

For balance of properties I like m390 better. For a small precise knife, I like ZDP better. Two of my favorite knives are an m390 kitchen knife (TRC K.O.) and the Dragonfly 2 in ZDP (which is perfect for ZDP--small, light and very precise).


If you haven't tried ZDP, I'd definitely give it a shot. It's pretty different from M390. If you start to go down the rabbit hole of super long edge holding, have a look at K390 and especially Maxamet, too. :)

[Bill1170]

Both take a nice edge for me. M390 has an edge in corrosion resistance as awa54 noted, but they're both nice stainless steels.

Based on my unscientific layman knowledge, M390 seems to obtain its wear resistance from Vanadium carbides, while ZDP189 gets it more from massive amounts of carbon and a very high rockwell hardness.

What that means in my experience is M390 is better at holding a toothy edge and slicing abrasive materials, while ZDP189 will do better than M390 with a polished edge.

That isn't to say you couldn't polish up M390 and run ZDP189 toothy, just that in my eyes that is how you'd play to the strengths of each steel.

They both exhibit top of the line edge holding for a small folding knife, neither should disappoint.

I find M390 a bit easier to sharpen, but neither steel challenges me in that respect. You'll definitely want diamonds for either steel if you plan to reprofile them.

Neither steel chipped out on me, even running thin edges on them.

Came here to comment, but Vivi has already eloquently stated what I came to say.

[Cycletroll]

Vivi pretty much nailed it! I second the Dragonfly although I do have an Endura and Delica too.
I will add that M390, 204p, 20cv are much easier to sharpen. I have experienced a slight oxidation haze on ZDP, bu t nothing bad. M390 is a better balance for EDC knives. ZDP is a monster for edge retention and has enough toughness for reasonable tasks.

[Loudenboomer]

Chromium content is be about the same on both 20CV and ZDP-189. I found it interesting several noted 20CV was a little more corrosion resistant then ZDP-189.

[vivi]

Chromium content is be about the same on both 20CV and ZDP-189. I found it interesting several noted 20CV was a little more corrosion resistant then ZDP-189.

I forget the details, but there is something about ZDP189 that makes it less corrosion resistant than the chromium content suggests. Hopefully someone with more knowledge can chime in.

[Cycletroll]

The high carbon soaks up the Chromium during carbide formation leaving less in solution to provide corrosion resistance. M390 has other carbide formers leaving Chromium free to provide corrosion resistance.