I Tested the Edge Retention of 48 Steels

Larrin said:
Nitro-V did not show an edge retention improvement over AEB-L and the toughness was somewhat lower. I prefer 14C28N for the corrosion resistance improvement.
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That makes sense. I was looking at the toughness vs hardness scale and interpreted that as edge retention. Seems Nitro-V is more marketing than anything considering it loses toughness to AEB-L without gaining edge retention.
 
In all my years of knives ive learned one thing. In a blind test id be unlikely to be able to tell much difference. I haven't used a lot of steels, but maybe 10. I can tell m390 is harder than sak steel. But in my practical use, that involves a heavy dose of inappropriate tasks, they all dull rather quick.
 
I realize I came in here rather late in the thread so here goes anyway.

The laymen who knows little if anything about steels does want to know from a practical standpoint which factory produced knife steels would be best for him to purchase in either stainless or carbon and what if any practical difference there is in actual use. Arguing how many angles can stand on the head of pin may be an interesting subject to some but entirely a waste of time to the average consumer who just wants some clear cut answers without having to take a course in metallurgy.

It would have been more informative if some black and white clear cut answers would have been stated as to what factory made knives being currently made in stainless or carbon (that are commonly available to the consumer) would be the best tool for the job. . Price of course is always a factor but the question is not one of price at all but which factory produced affordable stainless factory knives have the best edge retention (if properly heat treated) and factory produced knives made of carbon steel knives have the best edge retention by brand name along with heat treatment or lack there of . The laymen is not concerned with complicated explanations or hypothesis or speculation or exceptions to the rules of steel making but concerned with what is available and affordable to him across the counter at an affordable price and from the major knife makers. Whether to purchase D2 , 440a, b and c, aug 8 and 10 just to name a few of the steels the consumer often has to chose from is a question that is often asked over and over and that is "is it worth the extra money to pay more for a knife" with say aug 8 as compared to say run of the mill 440a etc. etc. In other words would the average Joe even know or see the difference or even care if all he had to do was sharpen it more often and pay way less for the product? Is one steel over another really that much better to the practical man who in most cases may use his knife once a year to gut a deer? It might make a difference to the professional chef in a restaurant or if affordable to the average house wife for use in the kitchen. Otherwise we are back to arguing over how many angles can stand on the head of pin.
 
bhp9 said:
I realize I came in here rather late in the thread so here goes anyway.

The laymen who knows little if anything about steels does want to know from a practical standpoint which factory produced knife steels would be best for him to purchase in either stainless or carbon and what if any practical difference there is in actual use. Arguing how many angles can stand on the head of pin may be an interesting subject to some but entirely a waste of time to the average consumer who just wants some clear cut answers without having to take a course in metallurgy.

It would have been more informative if some black and white clear cut answers would have been stated as to what factory made knives being currently made in stainless or carbon (that are commonly available to the consumer) would be the best tool for the job. . Price of course is always a factor but the question is not one of price at all but which factory produced affordable stainless factory knives have the best edge retention (if properly heat treated) and factory produced knives made of carbon steel knives have the best edge retention by brand name along with heat treatment or lack there of . The laymen is not concerned with complicated explanations or hypothesis or speculation or exceptions to the rules of steel making but concerned with what is available and affordable to him across the counter at an affordable price and from the major knife makers. Whether to purchase D2 , 440a, b and c, aug 8 and 10 just to name a few of the steels the consumer often has to chose from is a question that is often asked over and over and that is "is it worth the extra money to pay more for a knife" with say aug 8 as compared to say run of the mill 440a etc. etc. In other words would the average Joe even know or see the difference or even care if all he had to do was sharpen it more often and pay way less for the product? Is one steel over another really that much better to the practical man who in most cases may use his knife once a year to gut a deer? It might make a difference to the professional chef in a restaurant or if affordable to the average house wife for use in the kitchen. Otherwise we are back to arguing over how many angles can stand on the head of pin.
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Larrin's epic study is meant for sophisticated users, and as such can be a difficult read for beginners or casual knife users.

If you stick to high-quality brands, pretty much all the steels they use will be fine.
 
bhp9 said:
It would have been more informative if some black and white clear cut answers would have been stated as to what factory made knives being currently made in stainless or carbon (that are commonly available to the consumer) would be the best tool for the job.
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Most knife articles online are of this sort already. Where do they get good factual info to base their recommendations on if not from sources like Larrin? Having published research is important because otherwise 'layman' articles are anecdotal.
 
bhp9 said:
I realize I came in here rather late in the thread so here goes anyway.

The laymen who knows little if anything about steels does want to know from a practical standpoint which factory produced knife steels would be best for him to purchase in either stainless or carbon and what if any practical difference there is in actual use. Arguing how many angles can stand on the head of pin may be an interesting subject to some but entirely a waste of time to the average consumer who just wants some clear cut answers without having to take a course in metallurgy.

It would have been more informative if some black and white clear cut answers would have been stated as to what factory made knives being currently made in stainless or carbon (that are commonly available to the consumer) would be the best tool for the job. . Price of course is always a factor but the question is not one of price at all but which factory produced affordable stainless factory knives have the best edge retention (if properly heat treated) and factory produced knives made of carbon steel knives have the best edge retention by brand name along with heat treatment or lack there of . The laymen is not concerned with complicated explanations or hypothesis or speculation or exceptions to the rules of steel making but concerned with what is available and affordable to him across the counter at an affordable price and from the major knife makers. Whether to purchase D2 , 440a, b and c, aug 8 and 10 just to name a few of the steels the consumer often has to chose from is a question that is often asked over and over and that is "is it worth the extra money to pay more for a knife" with say aug 8 as compared to say run of the mill 440a etc. etc. In other words would the average Joe even know or see the difference or even care if all he had to do was sharpen it more often and pay way less for the product? Is one steel over another really that much better to the practical man who in most cases may use his knife once a year to gut a deer? It might make a difference to the professional chef in a restaurant or if affordable to the average house wife for use in the kitchen. Otherwise we are back to arguing over how many angles can stand on the head of pin.
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“Best” is SO subjective though. The steel that is the best for your usage scenarios on a day to day basis may be completely different from what is the best for my uses. Maybe person “A” only cuts paper and values edge retention above all else (hello 15v or 10v). Maybe person “B” really likes to sharpen and keep their knives razor sharp at all times and doesn’t care about edge retention (hello super blue or similar). Maybe person “C” wants a really good balance of toughness, edge retention, and ease of sharpening (CruWear). Maybe person “D” works in a salt water environment and values corrosion resistance above all else (hello lc200n or similar). Maybe person “E” is all about toughness (3v or similar). And maybe person “F” wants a nice balanced steel for a really reasonable price (14c28n). For the undiscerning/indiscriminate customer, I imagine any of the commonly used steels from a reputable knife manufacturer would provide more than sufficient edge retention and toughness for day to day use.

Something that I would like to see is some sort of test that helps pinpoint how much toughness and edge stability is actually needed for the average knife user on a day to day basis for EDC tasks. With a proper heat treat, I think the average user (or at least enthusiast) could easily get by with a high edge-retention, low toughness steel like 10v with little to no issues.
 
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The first thing the layman needs to do is decide the job. Then learn to sharpen or decide to pay for sharpening. Before those issues are addressed, steel choice is irrelevant.
 
Wow awesome, best ever testing with a catra machine. I haven't read it yet but I am looking forward to it! Thanks again for sharing Larrin!
 
Larrin said:
The "loses initial sharpness" thing is one that comes up frequently over the years in reference to all sorts of steels. Ironically in this case I've also seen many people say it about ZDP-189. Until there is some clear pattern or a standardized test I can't take it any more seriously than anecdote. Perhaps if people only said it about coarse carbide steels and not fine carbide steels, or only when comparing steels of different hardness. But the only trends I have seen are bias and placebo.
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I think that when most people talk about "loosing initial sharpness" they are probably referring to microchipping at the apex, causing the apex to become wider and rougher, without any visually apparent change (edge rolling or macroscopic chipping).

I would assume that a Brubacher Edge Sharpness Scale (BESS) and a microscope could be used do a study on this? A methodology similar to this study seems like it would work. The applied stress to the edge would need to be low enough that macroscopic plastic deformation and chipping would not occur. I think that one would want to use a non-abrasive material to minimize loss of sharpness due to abrasion.

Alternatively, it seems like taking the derivative of the CATRA cut distance vs. cut # curve (for only the first two or three cuts) seems like a way that you could analyze this without doing any additional testing.
 
Larrin said:
With CATRA testing higher wear resistance steels do better in early cuts as well as later cuts: https://knifesteelnerds.com/2018/11/26/steel-edge-retention2/

As to whether there is any micro-chipping or rolling in “real” cutting that would depend on how they are using the knife.
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If I remember correctly, the idea that high-wear steels quickly lose their initial sharpness started with the early batches of S30V, where micro-chipping was a real issue because of slow quenching during the heat treat. S30V makers have overcome that problem, but the conventional wisdom remains.

Nonetheless, most high-alloy, high-hardness steels are not very tough; so in real world use, micro-chipping can be an issue, depending on the knowledge and skill of the user.
 
Great job all around. Sorry about those costs, but at least you have your own catra now.

Really great how you further confirmed your model's ability to predict cutting performance with real world repeatable and verifiable tests open for anyone to actually try themselves. Catra testers are out there in use, just ask. Lots of people have already done it. Just not *this* well.

Maybe one day it will be enough to satisfy the questions and criticisms. Or not. Knives are all about the magic and mystery.
 
Larrin Larrin - can you point me to some more complete information on K390? I see very little mention of it in this paper (good night, what an undertaking! Thank you!). It seems one of a few you did not get test for toughness (quoting: . I have tested the toughness for all but 7 of the steels: Z-Max, BD1N, K390, S125V, S90V, S60V, and Vanadis 8.) I'd like to see how it stacks up compared to some other high end carbon steels. Purely anecdotally from my PM2 in K390, it seems pretty tough and holds a great edge.
 
I would expect K390 to have similar toughness to 10V. But Bohler claims improved toughness over 10V so there is a chance it is somewhat better.
 
Larrin said:
I would expect K390 to have similar toughness to 10V. But Bohler claims improved toughness over 10V so there is a chance it is somewhat better.
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I read in your article about the history of M390 where you wondered why Bohler used more expensive tungsten instead of upping molybdenum to the same effect. Why do they keep using tungsten vs. upping the molybdenum even in K390?

K390
jJl9Hfr.png
 
Mrs_Esterhouse said:
I read in your article about the history of M390 where you wondered why Bohler used more expensive tungsten instead of upping molybdenum to the same effect. Why do they keep using tungsten vs. upping the molybdenum even in K390?

K390
jJl9Hfr.png
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My guess is they attempted to differentiate from 10V to make the grade more “patentable.” The 10V patent had expired but some unique nature must be demonstrated, or at least claimed, to patent the steel. You can read the original patent to see if you think their reasoning makes more sense than mine: https://patents.google.com/patent/EP1382704A1/en
 
We need to find a way to incorporate "upsidaisium" into these steels.
 
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