D2 and primary carbides

[DocNightfall]

I notice that D2 seems to be a popular steel for outdoor-use knives.

I thought that large primary carbides are correlated with lower toughness, obtainable sharpness and edge stability. Is there a specific advantage in steels having large carbides?

 

[mete]

Wear resistance ! IIRC Crucible was working on a CPM version of D2.You could do an experiment with CPM154 vs 154CM and see for yourself.

 

[hardheart]

sprint run of CPMD2 Militaries & Kershaw Tyrade with CPMD2 cutting edge are coming.

Phil Wilson also did a cutting test with a blade he made from it.

 

[DocNightfall]

Wear resistance ! IIRC Crucible was working on a CPM version of D2.You could do an experiment with CPM154 vs 154CM and see for yourself.

I'd like to, but I don't exactly have the resources to conduct an experiment like that for myself, which is why I like to poke around this forum for more informed opinions.

So you mean to say that: a) large carbides are good for wear resistance and b) you find 154CM to be more wear resistant than CPM154?

 

[TALON158]

D2 steel is an excellent steel for "outdoor usage."
Have seen numerous posts by Cliff and others talking about it not being tough, large carbides, etc..
Im not a metallurgist, so are my friends who have been collecting far long than me..
D2 has been used for an extremely long time by veteran makers. Jimmy Lile is one that has been credited for using it first, although some might dispute that. Ted Dowell has been using it since the late 60s, Mike Leach, although not as well known as the rest, has been using it for forty years.
There are others but these 3 veterans have been using D2 primarily for their hunters, skinners, bowies and camp knives far longer than others have.
Best example is one of my buddies, who has taken more than 100 game in Africa. He only brings his D2 integral hilt and cap hunter made by Ted Dowell in the early 70s. D2 is a long proven steel.

 

[TinyDee]

Carbides, oh just go on with whatever you can dream up. D2 is, and will remain, a fine steel for knives. I worked with Jimmy Lile for some time and we always used D2 as our primary steel and it never failed. It is as good as any knife steel out there, period.

 

[hardheart]

The outdoor usage thing is way too broad, chopping wood and skinning animals are very different tasks. D2 will slice for quite a while and is fairly stain resistant. There's lots of outdoor use it could apply to that doesn't involve beating on it with a baton, so it is appropriate for different tasks, indoors or out.

 

[Cliff Stamp]

I thought that large primary carbides are correlated with lower toughness, obtainable sharpness and edge stability.

Yes.

Is there a specific advantage in steels having large carbides?

Large no, high carbide fraction gives high wear resistance which is important for some knives like skinners and such.

I'd like to, but I don't exactly have the resources to conduct an experiment like that for myself, which is why I like to poke around this forum for more informed opinions.

Contact me if you are interested in comparing CPM-D2 vs D2.

Carbides, oh just go on with whatever you can dream up.

Carbides are a dream? Ride a yellow submarine lately?

-Cliff

 

[Cliff Stamp]

FACTS about D2 :

http://www.cutleryscience.com/reviews/blade_materials.html#T_D2

Carbides and edge stability :

http://www.bladeforums.com/forums/showthread.php?t=344902

and finally :

"In general, the higher the volume fraction of primary carbides, the higher the wear resistance of the tool steel, and the lower its toughness and hot workability."

This is from steel patents for high carbide steels, you can find it directly in Crucible's patents for their steels. They argue that the use of Vanadium is important because you can achieve the wear resistance of steels like D2 with LESS carbides if you use vanadium vs chromium as the carbide former because vanadium is a harder carbide. As there are less carbides the toughness is higher. These are the FACTS, it has NOTHING to do with belief/dreams.

Ref:

http://appft1.uspto.gov/netahtml/PTO/search-bool.html

Yes people use D2, has anyone actually COMPARED these D2 knives to knives out of 52100 and other much tougher and higher edge stability steels to see which one performs as SUPERIOR tool when the edge angles are highly refined?

-Cliff

 

[searcher]

D2 is the standard steel used for metal shear blades (and often for metal cutting dies). D2 is the steel used to cut (mild) steel. I don't know if this makes it a good knife steel or not. Just an interesting fact; draw your own conclusions.

 

[Broos]

which one performs as SUPERIOR tool when the edge angles are highly refined?

I think of a highly refined edge as a polished edge. So you say 52100 will win over D2 in a push cutting or chopping test with a polished edge. At least in my opinion, I would not call a 80 grit edge a highly refined edge. I have not heard often of D2 being recommended as a large chopping knife, but by the same token there are some out there that folks have got good use out of large D2 knives (Kershaw I think has one available). I would not be afraid of using a large D2 knife, but I wouldn't be hitting the spine with a hammer, either.

But which steel will win in the typical use of a D2 knife - as a hunter sized slicer or a utility knife? Is a push cutting or chopping test the best test to determine which steel is "best" for these uses?

 

[mito0]

...has anyone actually COMPARED these D2 knives to knives out of 52100 and other much tougher and higher edge stability steels to see which one performs as SUPERIOR tool when the edge angles are highly refined?

-Cliff

as a matter of fact, someone did.
from the "facts about D2" site you linked:

In edge retention the D2 blade consistently outlasted the 52100 knife on the mat cutting which out cut the other two steels. (L6 and 1084)

 

[DocNightfall]

I wasn't intending to imply that D2 was a bad steel. Maybe I should rephrase my initial question.

What I meant to ask was:
Are steels with large primary carbides (D2, 154CM, etc.) more suited to cutting certain media (softer, harder, fibrous, etc.) , or are they more suited to certain types of cutting (chopping, push cut, slice, etc.) than steels with equivalent carbide volume but with smaller carbides?

Another way to phrase the question could be:
Are there any scenarios wherein 154CM/D2 would outperform CPM154/CPMD2?

 

[Cliff Stamp]

In edge retention the D2 blade consistently outlasted the 52100 knife on the mat cutting which out cut the other two steels. (L6 and 1084)

Yes the wear resistance is higher, now read the other pats which talk about the drawbacks.

Another way to phrase the question could be:
Are there any scenarios wherein 154CM/D2 would outperform CPM154/CPMD2?

They are much cheaper. But other wise no, I have not seen any arguement of evidence that the P/M is inferior in any way aside from cost. There have been some loose statements about voids but no direct and clear experimental support.

-Cliff

 

[mito0]

Yes the wear resistance is higher, now read the other pats which talk about the drawbacks.
-Cliff

i did, and it looks like there are instances where a D2 knife would be a clearly superior tool.

maybe i'm just reading you incorrectly - your posts seemed a bit dismissive of D2 supporters, but it seems to be an excellent steel for certain applications. i don't see any evidence that another good steel like 52100 is clearly superior to D2 overall, as your earlier post seemed to suggest. they both easily outperform each other on different tasks.
like i said, maybe i just misunderstood your intent.

 

[Cliff Stamp]

i did, and it looks like there are instances where a D2 knife would be a clearly superior tool.

Yes, I said that in the above :

Large no, high carbide fraction gives high wear resistance which is important for some knives like skinners and such.

To clarify, having large carbides is not an inherent advantage, but having a lot of them can be if the knife will benefit from high wear resistance and some types do, depending on the user's wants/needs.

-Cliff

 

[DocNightfall]

They are much cheaper. But other wise no, I have not seen any arguement of evidence that the P/M is inferior in any way aside from cost. There have been some loose statements about voids but no direct and clear experimental support.

That's all I wanted to know. Thanks!

 

[mito0]

Yes, I said that in the above :



To clarify, having large carbides is not an inherent advantage, but having a lot of them can be if the knife will benefit from high wear resistance and some types do, depending on the user's wants/needs.

-Cliff

ah, i just misunderstood what you were saying.

 

[me2]

There have been some loose statements about voids but no direct and clear experimental support.

-Cliff

Was this loosely alleged due to less than 100% density, or some other cause of voids?

 

[Phil Wilson]

Doc, On the question of whether the CPM version of 154 and D2 would have better performance I can offer what I have seen with some testing so far. With 154 the CPM version has a higher obtainable hardness and due to the CPM structure can be used with sucess at that higher hardness. 154 Cm works best at 60 or so. The CPM version seems best at 62. That couple point hardness makes a difference especially when cutting rope or in the field. If the two are compared at the same hardness, say 60 then the CPM does not seem to have a large enough
advantage to be easy to detect. I have only made a couple knives with CPM D2 and have not done any direct comparisons but my sense is that this one would act the same. PHIL