What would you rather have AUS 8 or 440C?

[thombrogan]

ATS-34/154Cm doesn't have near the chrome content of 440 series. Hard to compare them as steels. I would have a hard time imagining Crucible saying they were the same?

In this page from Crucible, 154CM is referred to as 440C modified.

 

[Michael Lovett]

Thanks Sal! and what Thom says is correct. Cliff, according to what you are saying D-2 would be of lesser performance than Aus-8 due to it's larger carbides. I know of no one that uses the heck out of a knife that would say that this is the case. Bob Dozer has made quite a name for him self using it. I too use a great deal of it. and several CPM steels as well. Can you tell me of any maker in the USA That is using the steels you speak of. I know a heck of a lot of the top makers in the world personally. I don't know of a one using it or 420. If it is as good, why not. If they are using it. Tell me who. And I'll be on the phone with them. Anyone? Mike

 

[Cliff Stamp]

...according to what you are saying D-2 would be of lesser performance than Aus-8 due to it's larger carbides.

It would have lower edge stability yes, this isn't a theory it is measured fact.

Can you tell me of any maker in the USA That is using the steels you speak of.

All the ABS guys using high stability steels like 1095 have the same viewpoint. If you want the same steel name (which should make no difference) P.J. Tomes uses Sandvik steels which have essentially no carbide at all, much lower than AUS-8 for example.

I know a heck of a lot of the top makers in the world personally. I don't know of a one using it or 420. If it is as good, why not. If they are using it. Tell me who.

Landes advocates 420HC over 440C, you can read why in detail here :

http://www.cutleryscience.com/articles/edge_stability_review.html

The first thing you have to realize is that speaking of "performance" or "quality" in steel without specification is meaningless. S7 is not a higher or lower quality steel than D2. It is superior in some aspects and inferior in others. Any two steels will compare in that manner.

-Cliff

 

[me2]

I'm becoming more partial to AUS 8 after using both it and 440C. Given a choice of makers, the AUS 8 by Benchmade is what I would ideally want. The extra hardness is noticable, even when sharpening on a belt sander. It doesnt take longer, but the "feel" and sound are different. Of course, this could be due to geometry, but I still like the HRc 60 AUS 8 by BM.

Out of curiosity, if in 440C, the C stands for cutlery, what does the A and B in 440A and 440B stand for? All 3 are listed for cutlery in some of my references.

 

[Frank Hillary]

Hi Cliff,

Great thread!

Any idea of how hard is the steel around the carbides in corectly heat treated 440C? Is it softer than AUS8?

If the carbides fall out of the dege, don't that give us the serated edge that you say is so good? Where is the problem?

Best Reagrds
Frank

 

[Jaundice]

I have a Cold Steel tanto in AUS-8A. What is the consensus on the heat treat/hardness of these knives?

-John

 

[Cliff Stamp]

Any idea of how hard is the steel around the carbides in corectly heat treated 440C?

This, in general, is what is represented by the HRC rating.

If the carbides fall out of the dege, don't that give us the serated edge that you say is so good?

For slicing yes, that is why I noted that they work well for coarse edges. But if you want a high polish for push cutting then the performance is low, especially at acute angles.

-Cliff

 

[Frank Hillary]

Hi Cliff,

This, in general, is what is represented by the HRC rating.

-Cliff

Thanks for that

The HRC takes in the hardnes of the carbide as well. What about the steel around ithe carbides. When I did my aprenticeship I remeber doing a hardnes test on a microscope, but forgot what it was called. I could give you the hardness of tiny areas.

Best Regards
Frank

 

[Cliff Stamp]

Yes, but generally unless the carbide volume is insane, you are measuring the steel matrix. Now if you are asking if there is a variance in the hardness due to the carbide aggregation of alloying elements which leads to a increased chance of tear out - possibly. You can do micro-hardness tests on precision instruments which may be what you are referring to. Here is an example of carbide tear out from Landes steel book :

The steel looks like this :

The big white things are the carbides. The book is "Messerklingen und Stahl".

-Cliff

 

[Frank Hillary]

Hi Cliff,

Thank you for your answers and photos. I understand much better now.

Keep up the good work.

Best Reagrds
Frank

 

[thombrogan]

I have a Cold Steel tanto in AUS-8A. What is the consensus on the heat treat/hardness of these knives?

Hit or miss. Just like their Carbon V counterparts, you could get the best heat-treat offered for that steel ever, the worst, or any other variation. Plus, one man's 'optimal' is another man's 'crap.' The more important question is:

Are you happy with how your tanto cuts, holds an edge, and resharpens?

That's all that really matters.

 

[SaMX]

Cliff, while you are on the subject of carbide size, what are the carbide sizes in some other steels, such as VG-10, SV30, and ATS-34?

 

[Cliff Stamp]

ATS-34 is shown in the above and has carbides up to about 25 microns in size. VG-10 I have not seen the measurements for but will be slightly smaller due to the reduced molybdenum, but since the Chromium is the major carbide former I would expect them to still be around 15-20 microns. S30V is much smaller due to the P/M process, less than 10 microns. Here is a shot of S60V :

S30V will have a lower carbide volume so expect less segregation (clumping/intersectioning). Here is RWL34 (CPM154) :

Note the huge difference between this and ATS-34 (same steel, one is ingot and the other P/M). Note still though that there are many ingot steels with much finer carbides such as AEB-L :

So don't fall for the P/M line blindly. When the steel is of high alloy, especially high chromium, it will still have very chunky carbides, even if P/M as RWL34 clearly shows.

-Cliff