Why is 13C26 better?

Fortunately Kershaw has a lot more customers to satisfy than just us steel nerds. They keep their prices down by keeping their customer base broad and partially they keep their customer base broad by keeping their prices down (I like the symmetry there). The other way they keep a broad customer base is by protecting their reputation with a broad base. Key in doing that is not having their customer's knives "fail". We all know how abusive the average Joe customer is to his knives. If a knife is hard the tip will be broken off and the edge will be chipped (by obvious abuse) which will be blamed on shoddy design and manufacture. Kershaw needs to produce knives that are resistant to these failure modes even at the expense of edge holding or optimum edge performance. They need to guard-band their design and heat-treatment towards a measure of toughness. For those rarer customers who sharpen their own knives softer steel usually are less frustrating. An extremely hard blade may not even get up to scraping sharpness in a novice's hands. Whether it forms a burr or not is less an issue than whether you can even get to burr formation.

In the broad spectrum of knife manufacturers Kershaw leans towards the sleaker, more sophisticated proportions that flirt with vulnerability to customer abuse. I am surprised that they don't go more with the flow and produce saber-ground splitting wedges. I am very pleased that they would even consider switching from 440A to a Sandvik alloy. I am delighted that they would actually do it. Now I have to go out and buy another Leek and see if I can tell the difference. I was awfully surprised by how sharp my 440A Leek got. It is an example of a sophisticated design that I couldn't resist even though it was made out of 440A. It is the only 440A knife I have bought in 10 years. Oh, wait, there was that Chive I bought for an old friend.

So for my entertainment and edification I would love to see a Leek with a 13C27 blade at 63 RC, but I will be more than happy to have one at 59 RC. I might even have the blade heat treated again if I want to play with it at 63 RC.
 
One thing that strikes me in this forum is that Sandvik seems to be selling too cheap. At a higher price tag, would not a lot of your questions go away?

From my perspective, being a Sandvik fan, it performs well against any other steel grade out there. Thats including S30V and 154CM, but they are never talked about as cheaper alternatives, because of their price tag.

Any metallurgic or steel-fanatic out there kows that excessive amounts of Carbon/Molybdenium/Vanadium etc. just ends up as big primary carbides making the blade dull/microserrated. You can get the hardness and the edge retention you are looking for in 13C26, why pay more for 154CM?
 
Jeff Clark said:
So for my entertainment and edification I would love to see a Leek with a 13C27 blade at 63 RC, but I will be more than happy to have one at 59 RC. I might even have the blade heat treated again if I want to play with it at 63 RC.
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Typical as quenched (with cryo) hardness is 63-64, so to get 63 you'd have to have an extremely low temper, probably less than 300F.

On a different subject, as to whether Kershaw underhardens their 13C26, you don't have to underharden to get 55-57 Rc. Partly due to the lack of molybdenum, you can get 55-57 just by raising the tempering temperature while still keeping an austenitizing temperature that is plenty high enough. I believe that Uddeholm, for one (I don't know about Sandvik), recommends a tempering temperature that is pretty high, which would bring the hardness down in to that range, for their AEB-L. I think for a high production factory folder, 59-60 Rc is plenty sufficient as far as hardness goes. You're only asking for trouble if you want to go for maximum hardness in such widely distributed knives. 59-60 Rc could very well be a hardness that brings a peak combination of wear resistance and toughness, I don't think anyone has done any testing for toughness and wear resistance numbers at different hardnesses and/or heat treatments.

Edit: I didn't realize that underhardening could be seen as also meaning simply to heat treat it to a lower hardness than optimum. Underhardening in metallurgy refers to the actual hardening, as in the austentizing temperature.
 
I believe I mentioned this in an earlier thread, but the swap from 440A to 13C26 will be a running change. We do still have inventory and additional 440A to go through, but all 440A knives should be changed over by Feb/March 07.
Sorry, at this time I don't have a list of when specific models will make the switch.
 
JayAndersson said:
One thing that strikes me in this forum is that Sandvik seems to be selling too cheap. At a higher price tag, would not a lot of your questions go away?

From my perspective, being a Sandvik fan, it performs well against any other steel grade out there. Thats including S30V and 154CM, but they are never talked about as cheaper alternatives, because of their price tag.

Any metallurgic or steel-fanatic out there kows that excessive amounts of Carbon/Molybdenium/Vanadium etc. just ends up as big primary carbides making the blade dull/microserrated. You can get the hardness and the edge retention you are looking for in 13C26, why pay more for 154CM?
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That sounds kind of backwards to me. The Sandvik stainless grades, since they are primarily carbon and chromium, which are quite cheap compared to molybdenum and vanadium, allow them to keep the price low, among other things. There's no reason to raise the price. And, honestly, I don't think they would sell more if they raised the price. At least Sandvik wouldn't.
 
To Larrin,
I understand your point, although I'm not sure you understood mine, maybe I was not clear enough in my rambling.

I'm only adressing the performance discussion, not the price/cost of making steel. So I will rephrase my question a little.

Compared to the high-alloyed steels out there, how do you think 13C26 performs?

I've had knives in S30V, 154CM and D2 steel which I payed far more for than my Sandvik 12C27 knife (made from a european brand). Imho I belive that Sandvik stands up good against any of them, my D2 was worst by far. I did however have some personal issues admitting this since my cheapest knife was in fact my favorite. Had it been more expensive I would have expected it to perform better than if it was cheap.

I dont care about moybdenium if all it does is making my knife microserrated and overpriced, do you? I pay for the overall features of the blade, not 2% Mo.

How do you guys rank 13C26 against S30V, 154CM, D2, AUS6-8 etc?

//Jay
 
i was under the impression all these steels (aeb-l and sandviks) are recommended to be tempered at low (well relatively) temperatures? like 150-250°C or so for best corrosion resistance. btw jay welcome to the forum
 
I was not aware that the steel itself was any cheaper than 154CM but only that it was easier to work to make the blades which made it cheaper.

STR
 
STR said:
I was not aware that the steel itself was any cheaper than 154CM but only that it was easier to work to make the blades which made it cheaper.

STR
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i think its similar to 12c27 about 10€/kilo or so
 
JayAndersson said:
To Larrin,
I understand your point, although I'm not sure you understood mine, maybe I was not clear enough in my rambling.

I'm only adressing the performance discussion, not the price/cost of making steel. So I will rephrase my question a little.

Compared to the high-alloyed steels out there, how do you think 13C26 performs?

I've had knives in S30V, 154CM and D2 steel which I payed far more for than my Sandvik 12C27 knife (made from a european brand). Imho I belive that Sandvik stands up good against any of them, my D2 was worst by far. I did however have some personal issues admitting this since my cheapest knife was in fact my favorite. Had it been more expensive I would have expected it to perform better than if it was cheap.

I dont care about moybdenium if all it does is making my knife microserrated and overpriced, do you? I pay for the overall features of the blade, not 2% Mo.

How do you guys rank 13C26 against S30V, 154CM, D2, AUS6-8 etc?

//Jay
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For what I use knives for, 13C26 (well, in my case, AEB-L) is my favorite steel. I don't have any experience with AUS-6/8 so I'll exclude it from my comparison, though it may be similar, but however well made the AUS steels are, I know that Sandvik is of the highest quality with very little impurity. I've seen micrographs of a .65% C 13% Cr steel, and it had some larger primary carbides, whereas I know AEB-L does not, so I don't think all steels with that composition are created equal, the way it is made contributes too.

From my experiences, some guesses, some actual information, etc. here is how I rank AEB-L against S30V, 154CM, and D2. 1) I rank AEB-L as the very easiest to sharpen, it's not even close compared to S30V, 154CM, or D2. 2) It has the very finest carbide size, S30V is next but they are still considerably larger. 3) Edge retention is very good and just plain excellent for the extreme ease of sharpening. With Phil Wilson's rope cutting, it doesn't cut quite as long as 154CM, though the 154CM was one Rc higher, and Phil Wilson says he would group them in the same class. S30V will have much higher wear resistance, and D2 should probably cut about the same as AEB-L for slicing edge retention. 4) For push cutting I don't know much about it, but because of the very small carbide size, I think AEB-L might just beat out S30V for push cutting, depending on the thickness of the grind. 5) For corrosion resistance, I don't know much, but I know it's more than adequate for me, and I know it survives just fine in the dishwasher when heat treated properly, which 154CM tempered at 975F does not, it pits pretty badly. With the lower temper for 154CM, AEB-L might be better than in some applications, I think AEB-L might have more free chromium, but 154CM would excel in situations when molybdenum helps. I don't know about S30V. Of course, the corrosion resistance of D2 wouldn't even compare. 6) As for toughness, I think AEB-L is better than S30V, 154CM, and D2, primarily because of its much lower volume of much smaller carbides, though there are some other factors that contribute. I don't have any testing to back that up.
 
M Wadel said:
i was under the impression all these steels (aeb-l and sandviks) are recommended to be tempered at low (well relatively) temperatures? like 150-250°C or so for best corrosion resistance. btw jay welcome to the forum
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I've never seen a recommended temperature from Sandvik, and neither gives a range that I've seen. I've only seen a single temperature recommendation from Uddeholm on AEB-L.
 
Thanks M Wadel!
I never presented myself since I was absorbed by the discussions here. This is a great forum for a knife-crazed fan as myself.

I'm Jay and I have a big interest in knives, especially the steels. I have a metallurgic background from my university days. Being a swede and living in the "steel belt" of Sweden I have a fair level of steel knowledge and I know the knife steel makers Uddeholm and Sandvik quite well.

Here among custom knife makers 13C26 is THE steel, right know there is no (non-damaskus) steel blades that is of serious interest. Before 13C26 it was AUS6 and before that it was 12C27.

That is why I follow this thread with interest, 13C26 is considered the best out there in Sweden, even compared to high-alloyed steels. I would like to know what you guys think about 13C26, AUS6 and 12C27.

//Jay
 
STR said:
I was not aware that the steel itself was any cheaper than 154CM but only that it was easier to work to make the blades which made it cheaper.

STR
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It is cheaper.
 
Larrin,
Thanks for the elaborate answer, I appreciate it.

It would seem that in the end it's the size of the carbides that do a lot of the difference I think, and it is in line with my own experience.

Small carbides will give the hardness required->edge retention. Also it will allow the blade to be sharpened in a better way than a blade with bigger (primary) carbides.

For rope cutting I guess that a micro-serrated blade would advantageous, so the 154CM would be the best one when you really need the big carbides.

In what situations would Molly help? Is it not just a carbide former like carbon? In theory it would seem that you could achive the same characteristics with balanced C and Cr.

//Jay
 
hardheart said:
Did Phil Wilson use 154CM, or CPM 154 in his rope testing?
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He used both. His results are on this forum, I'm just too lazy to find the link. I think his first post says that AEB-L got 80 cuts but it actually got 90 (or something like that), he corrected himself later but never changed the original post. CPM-154 cut longer than convential 154CM, partly due to being one Rc higher and due to the better microstructure over the conventional 154CM.
 
JayAndersson said:
Larrin,
Thanks for the elaborate answer, I appreciate it.

It would seem that in the end it's the size of the carbides that do a lot of the difference I think, and it is in line with my own experience.

Small carbides will give the hardness required->edge retention. Also it will allow the blade to be sharpened in a better way than a blade with bigger (primary) carbides.

For rope cutting I guess that a micro-serrated blade would advantageous, so the 154CM would be the best one when you really need the big carbides.

In what situations would Molly help? Is it not just a carbide former like carbon? In theory it would seem that you could achive the same characteristics with balanced C and Cr.

//Jay
Click to expand...
Molybdenum actually forms very little carbides in 154CM, something like 3.5% is in solution with the lower temper. It contributes to corrosion resistance, hardenability, temper resistance, and to upper tempering, and I've seen conflicting reports that it contributes to toughness. I think they used so much because it was designed as a bearing steel, which may require higher operating temperatures, which requires an upper temper. As an example of why it might be better than a balance of C and Cr, 19C27 offers a very high potention for hardness, with a sacrifice for corrosion resistance. If you add more chromium, you basically end up with 440C. If you add molybdenum, you end up with 154CM, that has a similar potential for hardness, but higher corrosion resistance, plus the other benefits of molybdenum; however, I think 19C27 has a lower carbide volume, which means it likely has higher toughness. I don't know a whole lot about molybdenum, but you can add up to 1% molydenum for some corrosion resistance and temper resistance without throwing your C and Cr balance too far off, though it still lowers the potential C and Cr in solution. The more you add, the more it changes the balance. 154CM's phase diagram looks way different than just a C and Cr diagram. And a .8% Mo, C/Cr phase diagram is a little different than a plain C/Cr diagram as well, you can see the differences in the free online Verhoeven book.
 
if i recall correctly the molybdenum is added to make the steel resistant to high temperatures so it doesnt go soft, when tempering, like in hss. i also think it forms bigger more complex carbides when there is Cr around. if you add enough of it to the steel, you have a secondary hardening steel (but dont quote me on that i might be way off, need to find my books..)

the carbides might be small in these steels but i think the biggest advantage is the tiny grain structure (the carbides are situated between these grains), thats why they use it for razors and similar. ive read 13c26/aeb-l is very very fine grained
 
M Wadel said:
the carbides might be small in these steels but i think the biggest advantage is the tiny grain structure (the carbides are situated between these grains), thats why they use it for razors and similar. ive read 13c26/aeb-l is very very fine grained
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Carbide size contributes more to a keen edge than grain size, but it also has a very fine grain size. Obviously, if it's a razor steel, it must have the ability to take and keep a very keen edge. For high end custom knives, especially, where we often have very thin grinds, AEB-L/13C26 is great.
 
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