How brittle is D2?

A large blade is going to be subjected to more stress and impacts by use alone. Most people who buy large blades are going to chop and baton with them. This puts more stress on the a blade then cutting rope.

I think some of you want it both ways. You say it is not brittle but you would not subject it to impacts. I'm sure it is fine for cutting but this thread is about
how brittle it is.

Anyways maybe it is brittle maybe it is not.. Never used it before. The only way to find out for me is to put one in a destruction test any compare it to the other steels that I tested.
 
Tom great post I happen to think the same as you about D2. I've been very happy with it in every knife I've had made from it, probably one of my fav knife steels. I do like other steels as well but when I see a knife made of D2 I take a second or third look at it. Tom can you give your views on M4 as I know litttle about it and have never used it.
 
noss4 said:
A large blade is going to be subjected to more stress and impacts by use alone. Most people who buy large blades are going to chop and baton with them. This puts more stress on the a blade then cutting rope.

I think some of you want it both ways. You say it is not brittle but you would not subject it to impacts. I'm sure it is fine for cutting but this thread is about
how brittle it is.

Anyways maybe it is brittle maybe it is not.. Never used it before. The only way to find out for me is to put one in a destruction test any compare it to the other steels that I tested.
Click to expand...

Kershaw makes a rather large camp knife called Outcast that would be interesting to see perform as it's D2. Just a thought ;)
 
noss4 said:
A large blade is going to be subjected to more stress and impacts by use alone. Most people who buy large blades are going to chop and baton with them. This puts more stress on the a blade then cutting rope.

I think some of you want it both ways. You say it is not brittle but you would not subject it to impacts. I'm sure it is fine for cutting but this thread is about
how brittle it is.

Anyways maybe it is brittle maybe it is not.. Never used it before. The only way to find out for me is to put one in a destruction test any compare it to the other steels that I tested.
Click to expand...

Not sure if you mean me, but I don't think I want it both ways.... Just because I don't want to use D-2 in a large chopper, doesn't mean I couldn't just that there are better choices.

Maybe we need to qualify what we mean when we say "Brittle".... The word makes me think of a blade shattering...


Tom
 
Kershaw makes or made the Outcast I think it was called. No one seemed to complain about it and its a bigger knife.

Isn't the cleaver in the Knives of Alasksa D2?

It seems some of you don't want to realize that even us fans of D2 recognize for some tasks there are better choices of steel. This takes nothing away from what we feel about it as an aggressive slicer.

STR
 
noss4 said:
Anyways maybe it is brittle maybe it is not.
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This is where Bladeforums shows how far it has degraded since Turber left. Debating if D2 is brittle is like debating if L6 has low corrosion resistance or if carbides weaken the tensile strength of steel, anywhere else these are just measured facts.

Tom Krein said:
If you drop the RC hardness, make them with thicker edge geometry you can easily make a D-2 knife that will work well as a big chopper.
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Have you used it extensively for several months for such role, I ask because I know if you do that for work on real woods out doors there is no way you would have this opinion. Large blades do not blunt by wear, they blunt by deformation and fracture. It simply takes far too long to wear even medium carbon steel chopping woods.

Having a lot of carbides weakens the edge means it will roll quicker and makes it more brittle so it will take fracture under less impact. Thus it takes more damage, lower edge retention, and the low grindability means it takes more work to sharpen. It really is one of the worst choices for such knives.

I think D-2 is BEST at a Rockwell hardness of 61 and ground nice and thin ...
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Have you tried it harder? You can reach 63 or so with oil+ cryo. It you are not impacting the blade into anything I don't see any need to make it weaker by drawing the temper. Dozier says it chips out too easy when it is harder, but Wilson says the same thing about 61 and draws it back even further to 59 or so. I would suggest if that is happening then change to a tougher steel, it isn't like there is a restriction of choices.

-Cliff
 
HELP !?!?


This thread is in danger of losing its value....its potential - to better educate buyers/users about the pros and cons of D2.


The most difficult part for people following this thread...is being able to compare apples to apples amongst the various comments.


We are missing some even basic definitions...words just being tossed around casually.

Things like "fracture", "brittle", "large carbides", "toughness", "strength", "wear resistance", "impact strength" and so on.

It is clear that many of the posts in this thread demonstrate misunderstandings of the meanings of these words/phrases and they are being used rather carelessly.



We've got "urban legend" mixed with "scientific fact"...and really no way to distinguish the two. We are potentially turning away people who might otherwise be truly interested in learning more about D2.


Even Cliff is showing a little carelessness in his use of the word "fracture". Let's clean up how we talk about these things...so that the misunderstandings can be settled.




Can we first agree on a few facts?

(and then debate the opinions)



Perhaps set some ground rules and standards? parameters?



Cliff, you wouldn't dare set out on proving a hypothesis without the above in the scientific world. Do us a favor and bring those standards here with you.
 
These type of threads settle nothing. I made a mistake for posting in it. When I have some proof on a test blade one way or the other and not an opinion. I'll return with my findings.

These threads are a roller coaster. Full of loops and twists but they always return to where they started.


When in doubt. TEST

PatriotDan: I have been looking at the Kershaw D2 for a test. I have seen this D2 debate for a while in many places." And I have seen many ask the question why D2 is not routinely offered in large blades ?
 
I am currently in the middle of some extensive (for me) rope cutting tests with a couple of knives, D2, and CPM D2. I hope to be done in a week or so, and will post the results here. This thread will be a nice segue into that, I hope that folks are interested in the results, I'll try to throw more steels into the tests when time permits.
 
Daniel Koster said:
Things like "fracture", "brittle", "large carbides", "toughness", "strength", "wear resistance", "impact strength" and so on.
Click to expand...

Fracture is a large area, specific to the discussion here is brittle fracture where the steel fails with little energy absorbed as it cracks rather than deforms, this is straightforward to understand. This is the nature of D2, debating it is just completely absurd and shows how pointless it is to discuss anything on bladeforums which opposes current popular knife culture. You might as well debate if M2 has hot hardness. Here is a direct quote :

"High carb, high chromium steels such as No. 610 steel achieve their wear resistance because of a chemical balance which renders them notch sensitive and low in ductility. Meaningful tensile data are unavailable ..."

No. 610 steel is D2, note the steel is that brittle that a tensile test can not even be performed. Here are some again actual published facts, D2 is so brittle that at 56 HRC it is as plastic (can deform) as L6 is at 61 HRC. If both are compared at 60 HRC then L6 is about 10 times as plastic. Read that last sentance a few times. Ten times as plastic. Again these are actual facts.

As for carbides, primary carbides in cutlery steels range from 1 to 50 microns and the volume fractions common are 1-25%. AEB-L has carbides of about 1 micron with a volume fraction of a few percent, depends on how it is austenized, D2 hits at the extreme upper range of 50 microns in size at about 15% by volume, Landes has direct micrographs of both of these steels. The volume fraction can be verified in Verhoevens work (where he severely critizes D2 type steels for cutlery) and the patent information on 3V by Crucible.

Landes also directly measured the ability of these steels to resist deformation at the edge and found that D2 is very low in this regard as the carbides break out, it is the lowest of the cutlery steels. There is a huge volume of research on this in germany which started about a hundred years ago and how such measurements translate to direct performance in hand as opposed to machine cutting. It is why they stopped doing CATRA style testing over 50 years ago as it did not correlate to blade wear in hand use.

Cliff, you wouldn't dare set out on proving a hypothesis without the above in the scientific world. Do us a favor and bring those standards here with you.
Click to expand...

I can actually quote references for everything I noted, plus actual compariative cutting to support the performance statements. I would like to see the same done for the rest of the above. You want to start talking about standards for discussion I think there are a few other areas you might want to examine first.

-Cliff
 
Cliff when I gave you crap for breaking that Dozier D2 blade in a plank of wood and prying with it to make a bowl I simply was pointing out how you should have known in advance exactly what would happen to the tip. But instead you went into one of your diatribes about how and why D2 was not that brittle when I used that same term "Brittle" in my post! Now its all different huh?

You suggest now that you know and are informed and yet you acted and even wrote so that one thing stood out about the way you broke that tip. It surprised you! Rather than just say to me, you are right, I should have known better, or I did suspect it migh break you went on to argue with me about it and justify it as a type knife that should handle it because of all the concreate stabbing you did with it and then give me crap for calling it brittle as I recall pointing out on more than one post how it is not that brittle.

Then toward the end you went on to claim that because of me people would read such things about the ease of tip breaking with it or other such class of steels when all I said was that if D2 had a weak spot it was in the tips on those thinner Dozier knives but you blamed me instead for causing people to lose track and not stay focused with the cutting results.

You are a piece of work my man~! A real piece sometimes. Maybe you should review and re-read some of your own diatribes before posting.

STR
 
witchhunter said:
if D2 is a poor choice for a large chopper wouldn't it also be a poor choice for a large fighter?
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Yes, even more so, bones are harder than wood.

STR said:
Cliff when I gave you crap for breaking that Dozier D2 blade in a plank of wood for not knowing in advance exactly what would happen to the tip you went into one of your diatribes about how and why D2 was not brittle when I used that same term!
Click to expand...

Complete misrepresentation of what I said. The reality was that in the same thread I posted the following before you entered :

"D2 is one of the more brittle tool steels, it has little flexibility and will tend to splinterize when it cracks, producing many fragments if you bend it to failure or impact it. It makes a nice light utility cutting steel, scraper etc., high wear resistance and decent hardness."

What I contended was your statement that D2 was so brittle it would be expected to snap by just stabbing it into the wood as you noted was a common failure of people using Dozier blades. My responce to that was :

"Unless there is a significant distal taper which leads the main body of the blade to bend and thus break that looks like a problem with the steel. Yes D2 has a low impact toughness, but it should not be that brittle."

Ref:

http://www.bladeforums.com/forums/showthread.php?t=342059

-Cliff
 
Yes but later on like the very next page you said, "It is not that brittle". The bottom line is all you really want to do is argue here Cliff.. Rather than agree with me that we were basically as informed about the steel and on the same page you would rather argue the point at all cost and defend your blade break.

I don't recall the order or when I came into the thread but if you posted that first and yet were surprised at how easy the tip broke what does that say about how well informed you really are? Not much. For that matter if you know all this and it is plainly evident you do then what is the sense in taking a hammer to a D2 blade to try to make it go through a car door hinge? These things speak loudly of contradiction to me.

All Dan does is mention some accurate observations and you want to define fracture for him rather than just say you know you are right, I'll rephrase. Or something of that nature. This is what causes the problem as I see it. You argue and defend, argue and defend. And comes across as a guy with a god complex, never wrong always the teacher and never the student.

Oh, and if Blade forums is so bad for you and you can't feel it is a good place to post please, let me show you the door. Please please.


STR
 
Cliff Stamp said:
Yes, even more so, bones are harder than wood.
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Can be, but live human bone is flexible and somewhat soft-ish....think green bamboo.

When an organism dies, the bone hardens very, very quickly.

Best Regards,

STeven Garsson
 
While I do not have extensive experience with D2, the two knives made of D2 that I have owned where probably the best stainless or pseudo stainless steel knives I have ever owned. They were razor sharp and had long lasting edges that did not ever chip out like my S30V and my 440C blades have.

Also, you can ask Less Robertson how he feels about D2, I remember him touting it's use in very tough blades, like Brends model 2. In fact I remember him touting it over Randalls forged O1 blades.

Busse himself (under SwampRat and prior to SwampRat) used D2 extensively and it sure was tough in those thin little swamprat blades.

I think people get cought up in steel types instead of blade design and Heat treat which are much more important factors imo.

You can make any steel crap. CPM3V, can be great, but give it to me and let me HT it and I will make it perform worse than a chinese $2 knife.:eek:

I would be more than happy to own a well made knife out of D2. :thumbup:
 
It's my opinion anyone who posts or implies D2 is any less than a great cutlery steel knows nothing about cutlery or steel.
I don't need any references to prove that,. Just use one.
 
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