Which Steel Has the Best Edge Retention?

Larrin

Larrin

Knifemaker / Craftsman / Service Provider
Joined
Jan 17, 2004
Messages
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I have two giant articles all about what controls edge retention in knives. I analyzed a huge database of CATRA experiments performed by a major knife manufacturer. I calculated an equation for estimating slicing edge retention based on steel, hardness, and edge geometry. It is easy to use with the provided carbide fraction numbers for every steel I could find published information for. The tables with carbide numbers are included in Part 1 with the steels present in the CATRA database and more in Part 2 which were not. Then I analyzed the sharpness loss curves themselves to see what conclusions we come to. Do high wear resistance steels lose their initial sharpness more quickly?
Part 1: https://knifesteelnerds.com/2018/11/19/steel-edge-retention/
Part 2: https://knifesteelnerds.com/2018/11/26/steel-edge-retention2/
 
I've never believed the adage that carbide-rich super steels lose their initial edge faster than plain carbon or low-alloy steels. Nice to see someone investigating it properly.

To contribute some less than scientific experience, S90V kitchen knives hold a razor sharp edge for a loooong time, even though few here would recommend that steel for such a task.
 
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Larrin said:
I’m not sure it adds anything to the discussion. I analyzed it here: https://knifesteelnerds.com/2018/09/03/ranking-the-steel-ranking-articles/
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Since your "gold" membership out ranks my common non paying membership, i removed my post that in your opinion your not sure it adds anything to the discussion.

And i thank you for bringing it to my attention Mr. Larin, i am sure your "Knife Steel Nerds" article will help everyone in a much better technical fashion then the one i posted and have removed.
 
snapshot2017 said:
Since your "gold" membership out ranks my common non paying membership, i removed my post that in your opinion your not sure it adds anything to the discussion.

And i thank you for bringing it to my attention Mr. Larin, i am sure your "Knife Steel Nerds" article will help everyone in a much better technical fashion then the one i posted and have removed.
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You are allowed to disagree with my opinion.
 
miso2 said:
That regression analysis is very satisfying and convincing.
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Only if results suit you.

Addendum: I read the whole article. I'm sure other forumers saw it but the only actual data that's convincing is that number of clean cuts increases with reduced edge angle. There is also a strong correlation with hardness and carbide content. However, these are no where near to telling you which is the better steel. The regression was used to predict efficiency in cutting (TCC) of a steel given edge geometry, hardness, carbide content, etc.

So the article predicts that CPM Rex 121 would be the best cutter (naturlich!) Among the steels used in regular production, it is predictably s90v and similar steels.
 
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hank_rearden said:
Only if results suit you.

Addendum: I read the whole article. I'm sure other forumers saw it but the only actual data that's convincing is that number of clean cuts increases with reduced edge angle. There is also a strong correlation with hardness and carbide content. However, these are no where near to telling you which is the better steel. The regression was used to predict efficiency in cutting (TCC) of a steel given edge geometry, hardness, carbide content, etc.

So the article predicts that CPM Rex 121 would be the best cutter (naturlich!) Among the steels used in regular production, it is predictably s90v and similar steels.
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I’m happy to hear the articles delivered what they promised.
 
snapshot2017 said:
Since your "gold" membership out ranks my common non paying membership, i removed my post that in your opinion your not sure it adds anything to the discussion.

And i thank you for bringing it to my attention Mr. Larin, i am sure your "Knife Steel Nerds" article will help everyone in a much better technical fashion then the one i posted and have removed.
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The whole point of the CATRA test is to see what we can learn about the single steel property of slicing edge retention by removing variables. The only variables tested and predicted for were edge angle and heat treatment (hardness, carbides etc.)
In the "steel ranking" reviews, the results can vary wildly from tester to tester and different companies treatment of the steels, edge geometry, materials cut etc.
Nothing wrong with real world testing, but it really doesn't tell us any of the "why's" about the steel being tested.
 
Let's see some values plugged in to the formula guys

CPM 10v at 67hrc and 25° inclusive.

−157+15.8×67−17.8×25+26.2×17.5

= 915 Predicted Total Cards Cut

CPM 15v at 63hrc and 30° inclusive.

−157+15.8×63−17.8×30+26.2×23

=907 TCC
 
Yes 100%.

What's great too is that folks can see how the carbide volume, hardness and most importantly edge angle can influence the edge retention

Larrin said:
Most of the steel ranking articles included very little real world testing. Mostly real world word-of-mouth.
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