Common for ZDP-189 to Rust?

T

TheReaper

Joined
Jul 16, 2006
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I have a knife with a ZDP-189 blade that’s starting to show signs of rust. Is this common for this type of steel? The knife is only a few months old, and has never seen anything close to water.

Thanks
 
My understanding is that ZDP-189 is not particularly prone to rust, and I haven't noticed any issues with my Delica, although I regularly keep all my knives clean and wiped down with Rem-Oil or CLP.
 
This is after cleaning, so I’m pretty sure it’s rust. It's hard to see,but here's a quick pic…

rust.jpg
 
Yep, it is true ZDP-189 started to rust on my delica,
while it was only laying on the night drawer. A bedroom must be a pretty harsh environment for a super steel :D :D .
 
It's my understanding that ZDP-189 is commonly laminated in the middle of other steels...such as 420 or 440. This means the actual cutting edge would be the only visible place where the ZDP-189 is present.

Maybe someone more knowledgeable than me on this can chime in here...but I'm wondering if the areas you indicated on the spine are not ZDP-189.
 
Well depends which knife. I don't know what Kershaw has been using for the Leek but the Delica is made from solid ZDP, not laminated. And, yes, ZDP is not an overly corrosion resistant steel. I believe it ranks even below ATS-34.
 
Most Stainless steel will rust. If you were carrying it in your pocket, the sweat that can get on your knife will cause rust fairly easily.
 
You know, I keep reading of you guys having trouble with rust and I live in the Washington, DC, area, an area noted for its humidity, yet I have no trouble with rust on most of my knives. I did get rust spots on a carbon steel knife but that was from the sheath, I think. What do you all do to get rust on S30V, ZDP-189, CPM440V, and others?
 
You know, I keep reading of you guys having trouble with rust and I live in the Washington, DC, area, an area noted for its humidity, yet I have no trouble with rust on most of my knives. I did get rust spots on a carbon steel knife but that was from the sheath, I think. What do you all do to get rust on S30V, ZDP-189, CPM440V, and others?
Click to expand...

I was wondering that myself. I have several ZDP delicas, Horns ( laminated) , S30V, D2, M2, 1095, 52100, 5260....etc., etc. NC is like a tropical rainforest too.

None of my knives have rust. The ZDP's seem to be more resistant than most of the other folders with high end steel too. Are you positive it's not some left over oil or something similar? Recall the reports of rust on H1 that turned out to be some other chemical reaction, or even left over steel from sharpeners that discolored and made it look rusty.

Reaper, what do you keep it lubed with and what did you use it before you cleaned it, and how was it cleaned? I'm curious. Joe
 
My WHKs Monarch w/ZDP 189 do not rust.
My WHK 154CM (DLC Coated), ATS34 do not rust, my CRK S30V do not rust.

I have been carrying the WHK's ZDP189s in the WHK leather sleeve in my front cargo shorts pocket all summer. I have it in the same pocket as my sweat-drenched hankerchief during this past summer in Los Angeles w/some severe heat waves.

BUT I do wipe them down with a Tuf cloth at the end of each day before I tuck them in at night. My daily routine. Also, use cleaning swabs to have a thorough cleaning each week.

Maybe it's the other steel in the laminate e.g. VG10, 440, that is rusting and not the ZDP itself ? Not a steel guru just a thought as a newbie.
 
Sorry I can't share any experiences with the ZDP but I had an AFCK with ATS-34 that I would tuck in the waistband of my shorts and go mountain biking (in the summer time, in NC) in and never did see any signs of rust. I would wipe it down when I returned, though.
 
I've had carbon steel Opinels, SAKs, VG10 and ATS55 Spydercos and some 420hc blades all drenched in sweat, water and acidic food residue before. Only thing I've ever done is rinsed them with water and dry them off. I've never used any type of oil for the blades. Ohio is a fairly humid place too, and I've never had any rust issues except for a fixed blade I put in the sheath when it was wet and it got minor rust on the spine. I still don't remember it being wet when I put it there, nor know how it got that way. *shrug*
 
ZDP-189 also has a massive amount of carbon which ties up a lot of the chromium in carbides. I would be very interested in q-fog data.

-Cliff
 
As I said already, Hitachi's own datasheet lists ATS-34 with an A for corrosion resistance and ZDP-189 with an A-. That should give you a vague idea. And pretty much indicates that there is relatively little free Cr left (for a stainless steel that is).
 
Rat Finkenstein said:
Most Stainless steel will rust. If you were carrying it in your pocket, the sweat that can get on your knife will cause rust fairly easily.
Click to expand...
I do work in a very hot and humid test lab. This is probably one of the reasons for the rust. The other being that I haven’t kept up with cleaning and oiling. I've used CLP to remove most of the rust, all but some spots on the spine and curve.

Thanks for all the replies! -Steve
 
It's not just the humidity that cause rust, its other things also. Rust is oxidation of the steel, this can be caused by many different kinds of chemicals such as acid gases in the air or compounds in your sweat (different people have different body chemistry). These are just some of the oxidative agents that can cause rust. Besides the oxidative chemicals your blade comes in contact with and its steel composition (e.g. how much chromium) the amount of rust you get also depends upon the way the steel was handled (e.g. hardening, tempering and polishing). Relative humidity does not indicate relative rusting ability.

If you wipe your knife every day with tough cloth or oil, your experience with rusting is not due to the steel type but more due to your protecting the blade with oil or the unknown secret ingredient in tough cloth.

If Hitachi says ZDP is rated less than ATS34 in corrosion resistance, than the types of rust you've seen are to be expected. ATS34 will rust in a similar manner.
 
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