Why is AUS-10 not more popular/used by mfrs?

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So Cliff,
In your cutting tests, are you able to differentiate between 440C, VG10, and N690?

I don't doubt your chart. I was just wondering if you could really tell them apart with empirical data.
 
knarfeng said:
... differentiate between 440C, VG10, and N690?
Click to expand...

Buck has compared 440C and 154CM and they are quite different at acute edges on CATRA cutting because the very large carbide of 440C makes the edge unstable and thus has low edge retention for push cutting. My point was more however in regards to steels of different classes. For example 440A and 13C26 have similar carbon contents but are very differnet steels because 440A has a much higher chromium content.

-Cliff
 
Howdy again Cliff,
I agree with that 440A vs 13C26 comparison. Makes perfect sense.

I guess I am trying to reach for a little understanding of the 440C,VG10, N690 group and how different they are from each other.

When I'm at work and specify an AMS spec alloy, say AMS 5599 (alloy 625), purchasing can buy alloy from 4 or 5 sources. Each company has its own version of alloy 625 that meets all of the AMS composition and performance requirements, but each is a different composition and may contain minor amounts of other metals in the alloy. To us, all these alloys are interchaneable and perform exactly the same.
How similar in performance are 440C, VG10, AUS10, and N690? You've done more empiracle testing of cutting performance than anyone else I know of. Do you have an opinion of any performance differences among these alloys?
Data is best, SWAG is better than WAG.
(SWAG= scientific wild ass guess. It means you don't have enough data to absolutely guarrantee that your answer is right, but you have some data upon which to base an opinion.)

And BTW, if I have slighted somebody and you got data, feel free to share.

Thanks,
Knarfeng
 
knarfeng said:
I guess I am trying to reach for a little understanding of the 440C,VG10, N690 group and how different they are from each other.
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These are fairly similar in that they are all about 60 HRC, high volume chromium carbide stainless steels with large carbide sizes, 25+ microns. One of the interesting things about N690 is that it is getting promoted now as a "superior" version of 440C due to cobalt, however several years back some of the same people critized the use of cobalt in knife steels (INFI, VG-10) because they were in competition with those steels. One of the many examples of selective logic in steel promotion.

Each company has its own version of alloy 625 that meets all of the AMS composition and performance requirements, but each is a different composition and may contain minor amounts of other metals in the alloy.
Click to expand...

Yeah, if you look at common alloys, 440C for example and 440B, these actually overlap in the extreme, but yet people will say that one is "superior" and the other is acceptable at best. However based on the composition you would expect that a fair amount of random samples of those two steels would in fact be identical.

Do you have an opinion of any performance differences among these alloys?
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440C has an extreme carbide size, 50 microns, due to the very high carbon and chromium, this limits the ability of the steel to take and hold a fine edge. The first I heard of this was by Clark who noted it years ago on the forums, he found that when Buck switched to 420HC the knives were much easier to sharpen to a high polish. Buck later published CATRA data which supported Clark's assertion. However if you are using either (or both) coarse finishes or obtuse angles (15+ degrees) then edge stability is effectively a non-issue and all of these steels will basically behave as high wear stainless. Unless the geometries were extremely similar I would expect those to dominate any relative performance.

This would contrast for example to something like 52100 vs D2 or 12C27M vs ATS-34 which are so different that they would be immediately separated by even novice level users because there are many to one changes in grindability, wear resistance, toughness, etc. .

-Cliff
 
Cliff Stamp said:
440C has an extreme carbide size, 50 microns, due to the very high carbon and chromium, this limits the ability of the steel to take and hold a fine edge. The first I heard of this was by Clark who noted it years ago on the forums, he found that when Buck switched to 420HC the knives were much easier to sharpen to a high polish. Buck later published CATRA data which supported Clark's assertion. However if you are using either (or both) coarse finishes or obtuse angles (15+ degrees) then edge stability is effectively a non-issue and all of these steels will basically behave as high wear stainless. Unless the geometries were extremely similar I would expect those to dominate any relative performance.

-Cliff
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more info. Using magna-flux testing on very thin edges (.1mm), the larger carbides tended to cause the edge to "break out". We learned this doing research on the Chalif model for Rabbi Yurman on his kosher butcher knives.

Steels like 440C & MRS-30 exhibited these charactaristics.

One of the arguments for powdered metals.

sal
 
Hi Sal, It's great to get your input on this. What did you finally use for the Chalif, MBS-26?
 
Thanx Jeff.

We used MRS-30. That's what caused the research. In this case, MBS-26 would have been better. We opted for the edge retention (also important in this case) but were quite ignorant (at the time) to edges that thin and how the molecular level of the chemistry could cause problems.

If we ever do a project like that again, We would seek the material with the very thin edge in mind. A small even grain structure

sal
 
Sal Glesser said:
more info. Using magna-flux testing on very thin edges (.1mm), the larger carbides tended to cause the edge to "break out". We learned this doing research on the Chalif model for Rabbi Yurman on his kosher butcher knives.

Steels like 440C & MRS-30 exhibited these charactaristics.

One of the arguments for powdered metals.

sal
Click to expand...
Thanks Sal,
So does the magnaflux testing show a difference between 440C, VG10, and AUS10?
(Sorry, I got a bad case of tunnel vision.)
 
Magnafluxing is used primarily to determine if there are microscopic cracks or flaws in the material.

sal
 
Sal Glesser said:
more info. Using magna-flux testing on very thin edges (.1mm), the larger carbides tended to cause the edge to "break out". We learned this doing research on the Chalif model for Rabbi Yurman on his kosher butcher knives.

Steels like 440C & MRS-30 exhibited these charactaristics.

One of the arguments for powdered metals.

sal
Click to expand...
Is the carbide size for VG-10 small enough that it doesn't exhibit any of those characteristics?
 
Sal Glesser said:
Thanx Jeff.

We used MRS-30. That's what caused the research. In this case, MBS-26 would have been better. We opted for the edge retention (also important in this case) but were quite ignorant (at the time) to edges that thin and how the molecular level of the chemistry could cause problems.

If we ever do a project like that again, We would seek the material with the very thin edge in mind. A small even grain structure

sal
Click to expand...

Hi Sal,

I realise that this is a VERY old thread, but I have been searching for information on this topic and found very little. How thin does one sharpen a Calif? Is it as low as 12 degrees inclusive?

What do you believe is the optimal steel and heat treatment?

Would you be willing to make another set/run?

I can't imagine that there is a high demand, but I would like to learn Schita.

Mark
 
AussieMark, rather than needlessly bringing a thread back from the dead (which will probably never be seen by Sal), how about just going to the Spyderco forum and either start a new thread or perhaps send an email. Much more likely to get a prompt and timely response.
 
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