How does ZDP 189 work?

RevDevil said:
The specificity of the questions has been covered, believe me. Search for answers in the Spyderco forum. There are discussions going back 6 years, lots of good information and part of the fun is being able to read what was once written and possibly thought to be true versus what we know now. That is how we learn. My favorite ZDP knife of all time that is readily available and affordable is the Stretch/Endura. Right around $100 gets you some good stuff.
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The ZDP FRN Stretch is an all star for sure. That's another piece of the puzzle, I'll pick the Stretch over knives that have steels that might fit my needs better because the design is so damn good. It's a small part of the reason I consider Sal Glesser to be the best knife designer of our time.
 
Insipid Moniker said:
The ZDP FRN Stretch is an all star for sure. That's another piece of the puzzle, I'll pick the Stretch over knives that have steels that might fit my needs better because the design is so damn good. It's a small part of the reason I consider Sal Glesser to be the best knife designer of our time.
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:thumbup: I carry a blue FRN ZDP Stretch as a backup knife in my pack.
 
Every knife I've seen with ZDP-189 has been a light to medium use knife (Spyderco's FRN series, William Henry, etc).

It annoys me that people expect a "super" steel to be perfect at everything. Edge retention, corrosion resistance, and impact resistance. You have to give up in at least one of those to increase the others.

I love my ZDP Dragonfly 2, and use it as it was meant to be used. Chopping wood is not one of them.
 
Some super steels manage all three of those pretty damn well though. Like 3v.
K.O.D. said:
Every knife I've seen with ZDP-189 has been a light to medium use knife (Spyderco's FRN series, William Henry, etc).

It annoys me that people expect a "super" steel to be perfect at everything. Edge retention, corrosion resistance, and impact resistance. You have to give up in at least one of those to increase the others.

I love my ZDP Dragonfly 2, and use it as it was meant to be used. Chopping wood is not one of them.
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In comparison to what? If your comparing it to a stainless steel or h1 then yea, compare it to normal tool steels and regular carbon steels and you'll see VASTLY better corrosion resistance. Have you used it for any length of time? I have and so have many others and its pretty well known 3v resists rust pretty damn well.

I get what your saying as far as people expecting one steel to do it all, no one steel is as rust resist as h1 and as tough as s7 and has the edge retention of s110v.

That said certain steels stand head and shoulders over others in all three categories.
 
ZDP is pretty awesome IMHO; this is my third Spyderco in this steel. :thumbup::cool:

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It is my workhorse for around the house/yard and gets used for a variety of tasks. I buff the edge regularly on my slotted paper wheel, or strop on a blue jean strop loaded with autosol. The edge actually feels sharper with use sometimes which seems unlikely; it may just be my imagination... :rolleyes:

I've only experienced slight blunting of some of the serrations and have yet to resharpen due to the buffing/stropping regimen. :thumbup::cool:
 
DeadboxHero said:
ZDP 189 notably has 3% carbon and 20% chromium.

It also has the ability to be heat treated to 67hrc without shattering like glass at the edge.

My question is how does all this come together?

Are chromium carbides able to lock into the iron matrix better then vanadium?

What allows for both hardness and toughness?
Is there something intrinsic about zdp189 that allows for 67hrc?

Thanks for the info guys.
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Gotta love Wikipedia

https://en.m.wikipedia.org/wiki/Heat_treating#Hypoeutectoid_alloys

"Eutectoid alloys Edit
A eutectoid alloy is similar in behavior to a eutectic alloy. An eutectic alloy is characterized by having a single melting point. This melting point is lower than that of any of the constituents, and no change in the mixture will lower the melting point any further. When a molten eutectic alloy is cooled, all of the constituents will crystallize into their respective phases at the same temperature.

A eutectoid alloy is similar, but the phase change occurs, not from a liquid, but from a solid solution. Upon cooling a eutectoid alloy from the solution temperature, the constituents will separate into different crystal phases, forming a single microstructure. A eutectoid steel, for example, contains 0.77% carbon. Upon cooling slowly, the solution of iron and carbon, (a single phase called austenite), will separate into platelets of the phases ferrite and cementite. This forms a layered microstructure called pearlite.

Since pearlite is harder than iron, the degree of softness achieveable is typically limited to that produced by the pearlite. Similarly, the hardenability is limited by the continuous martensitic microstructure formed when cooled very fast.[9]

Hypoeutectoid alloys Edit
A hypoeutectic alloy has two separate melting points. Both are above the eutectic melting point for the system, but are below the melting points of any constituent forming the system. Between these two melting points, the alloy will exist as part solid and part liquid. The constituent with the lower melting point will solidify first. When completely solidified, a hypoeutectic alloy will often be in solid solution.

Similarly, a hypoeutectoid alloy has two critical temperatures, called "arrests." Between these two temperatures, the alloy will exist partly as the solution and partly as a separate crystallizing phase, called the "proeutectoid phase." These two temperatures are called the upper (A3) and lower (A1) transformation temperatures. As the solution cools from the upper transformation temperature toward an insoluble state, the excess base metal will often be forced to "crystallize-out," becoming the proeutectoid. This will occur until the remaining concentration of solutes reaches the eutectoid level, which will then crystallize as a separate microstructure.

A hypoeutectoid steel contains less than 0.77% carbon. Upon cooling a hypoeutectoid steel from the austenite transformation temperature, small islands of proeutectoid-ferrite will form. These will continue to grow until the eutectoid concentration in the rest of the steel is reached. This eutectoid mixture will then crystallize as a microstructure of pearlite. Since ferrite is softer than pearlite, the two microstructures combine to increase the ductility of the alloy. Consequently, the hardenability of the alloy is lowered.[10]

Hypereutectoid alloys Edit
A hypereutectic alloy also has different melting points. However, between these points, it is the constituent with the higher melting point that will be solid. Similarly, a hypereutectoid alloy has two critical temperatures. When cooling a hypereutectoid alloy from the upper transformation temperature, it will usually be the excess solutes that crystallize-out first, forming the proeutectoid. This continues until the concentration in the remaining alloy becomes eutectoid, which then crystallizes into a separate microstructure.

A hypereutectoid steel contains more than 0.77% carbon. When slowly cooling a hypereutectoid steel, the cementite will begin to crystallize first. When the remaining steel becomes eutectoid in composition, it will crystallize into pearlite. Since cementite is much harder than pearlite, the alloy has greater hardenability at a cost in the ductility.[8][10]

Effects of time and temperature Edit


Time-temperature transformation (TTT) diagram for steel. The red curves represent different cooling rates (velocity) when cooled from the upper critical (A3) temperature. V1 produces martensite. V2 has pearlite mixed with martensite, V3 produces bainite, along with pearlite and matensite.
Proper heat treating requires precise control over temperature, time held at a certain temperature and cooling rate.[11]

With the exception of stress-relieving, tempering, and aging, most heat treatments begin by heating an alloy beyond the upper transformation (A3) temperature. This temperature is referred to as an "arrest" because, at the A3 temperature nothing happens. Therefore, the alloy must be heated above the temperature for a transformation to occur. The alloy will usually be held at this temperature long enough for the heat to completely penetrate the alloy, thereby bringing it into a complete solid solution.

Because a smaller grain size usually enhances mechanical properties, such as toughness, shear strength and tensile strength, these metals are often heated to a temperature that is just above the upper critical temperature, in order to prevent the grains of solution from growing too large. For instance, when steel is heated above the upper critical temperature, small grains of austenite form. These grow larger as temperature is increased. When cooled very quickly, during a martensite transformation, the austenite grain-size directly affects the martensitic grain-size. Larger grains have large grain-boundaries, which serve as weak spots in the structure. The grain size is usually controlled to reduce the probability of breakage.[12]

The diffusion transformation is very time-dependent. Cooling a metal will usually suppress the precipitation to a much lower temperature. Austenite, for example, usually only exists above the upper critical temperature. However, if the austenite is cooled quickly enough, the transformation may be suppressed for hundreds of degrees below the lower critical temperature. Such austenite is highly unstable and, if given enough time, will precipitate into various microstructures of ferrite and cementite. The cooling rate can be used to control the rate of grain growth or can even be used to produce partially martensitic microstructures.[13] However, the martensite transformation is time-independent. If the alloy is cooled to the martensite transformation (Ms) temperature before other microstructures can fully form, the transformation will usually occur at just under the speed of sound.[14]

When austenite is cooled slow enough that a martensite transformation does not occur, the austenite grain size will have an effect on the rate of nucleation, but it is generally temperature and the rate of cooling that controls the grain size and microstructure. When austenite is cooled extremely slow, it will form large ferrite crystals filled with spherical inclusions of cementite. This microstructure is referred to as "sphereoidite." If cooled a little faster, then coarse pearlite will form. Even faster, and fine pearlite will form. If cooled even faster, bainite will form. Similarly, these microstructures will also form if cooled to a specific temperature and then held there for a certain time.[15]

Most non-ferrous alloys are also heated in order to form a solution. Most often, these are then cooled very quickly to produce a martensite transformation, putting the solution into a supersaturated state. The alloy, being in a much softer state, may then be cold worked. This cold working increases the strength and hardness of the alloy, and the defects caused by plastic deformation tend to speed up precipitation, increasing the hardness beyond what is normal for the alloy. Even if not cold worked, the solutes in these alloys will usually precipitate, although the process may take much longer. Sometimes these metals are then heated to a temperature that is below the lower critical (A1) temperature, preventing recrystallization, in order to speed-up the precipitation."
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Basically carbon mixes with the other elements producing a structure that can be forced into a hardened state. Some elements increase that ability, some keep grain size low, and coupled with the right hardening and tempering temperatures, make some steels capable of reaching a higher hardness. But I'm no metallurgist and got that info from Wikipedia so my post may not mean anything.
 
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I have only one blade in ZDP-189. It's an Endura, and I have a pretty good amount of use with it. It keeps an edge really well - all I've ever done is touch it up regularly on a high-quality ceramic rod, and it's performed great. The steel will stain on you, though, so you have to keep it clean and dry. My 2cents...
 
And


https://en.m.wikipedia.org/wiki/Hardness


"Dislocations provide a mechanism for planes of atoms to slip and thus a method for plastic or permanent deformation.[6] Planes of atoms can flip from one side of the dislocation to the other effectively allowing the dislocation to traverse through the material and the material to deform permanently. The movement allowed by these dislocations causes a decrease in the material's hardness.

The way to inhibit the movement of planes of atoms, and thus make them harder, involves the interaction of dislocations with each other and interstitial atoms. When a dislocation intersects with a second dislocation, it can no longer traverse through the crystal lattice. The intersection of dislocations creates an anchor point and does not allow the planes of atoms to continue to slip over one another[9] A dislocation can also be anchored by the interaction with interstitial atoms. If a dislocation comes in contact with two or more interstitial atoms, the slip of the planes will again be disrupted. The interstitial atoms create anchor points, or pinning points, in the same manner as intersecting dislocations.

By varying the presence of interstitial atoms and the density of dislocations, a particular metal's hardness can be controlled. Although seemingly counter-intuitive, as the density of dislocations increases, there are more intersections created and consequently more anchor points. Similarly, as more interstitial atoms are added, more pinning points that impede the movements of dislocations are formed. As a result, the more anchor points added, the harder the material will become."
 
This Endura ZDP-189 has been one of my main EDC knives since June 2013, when i reground it from a saber flat grind to a saber hollow grind on my Tormek.
I keep the tiny bevel on the plain edge part sharp on a Paper Wheel coated with 1 micron diamond compound.







As an example: last year i took this knife with on a 6 week US trip through 17 or 18 different states, and when i left home the plain edge part was hair whittling sharp.
Used the knife during our vacation for various kinds of EDC things, from opening plastic packages, slicing bread & sandwiches, fruit and other foods, whittle a bit on the odd stick, etc, and when i returned home the edge could still shave arm hair on skin level.
While this can all be considered rather light use, i'm very pleased with this kind of edge holding.
The knife is in my pocket while i write this.
 
shinyedges said:
I've been reading about vandis 4e for awhile now, been itching to try something in it. Supposedly very tough with excellent edge holding, similar to 3v. 4v is another I want to try, is it crucibles version of vandis 4e?
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4V and Vanadis 4E are basically the same steel. Used 4V in my old Ferrum Forge Ferrox and liked it a lot, even though I normally do not like carbon steels in EDC blades for folders at all.
Seems to have a little lower toughness than 3V at similar hardness, but it gains some wear resistance in exchange, so it has better general edge retention.
It's kind of a happy medium between 3V and M4 in my opinion.
 
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