I Tested the Edge Retention of 48 Steels

Larrin

Larrin

Knifemaker / Craftsman / Service Provider
Joined
Jan 17, 2004
Messages
4,844
Recently I was able to acquire a used CATRA machine, so I heat treated just about every knife steel I had, made 57 knives with the help of knifemaker Shawn Houston, and tested them all to see which cut the longest. For a few of the steels I did multiple heat treatments to look at a couple variables and to see the effect of hardness. I also compared edge retention and toughness to see which steels have the best balance of properties. https://knifesteelnerds.com/2020/05/01/testing-the-edge-retention-of-48-knife-steels/
 
That was a fascinating read. As you mention at one point in the article, it would be very interesting to test a subset of these steels on something like card stock with no silica impregnation. I'm curious to see how results differ in this less aggressive test media as you've previously shown that even after just a single stroke through the silica test media the edge is significantly damaged. I for one am not particularly interested in how well my knife can cut after the edge has been significantly damaged, I'm more interested in how well it can hold a keen edge in lighter workloads. If the results in plain card stock mirror that of the silica imbedded material then it allows for the CATRA results to be taken with a much smaller grain of salt. (I'm especially interested in the lower alloy and low carbide content stainless steels, i.e. 52100, AEB-L, O1, A2, 1095, versus a fairly common and well respected higher carbide content steel like S30V.)
 
CallumRD1 said:
That was a fascinating read. As you mention at one point in the article, it would be very interesting to test a subset of these steels on something like card stock with no silica impregnation. I'm curious to see how results differ in this less aggressive test media as you've previously shown that even after just a single stroke through the silica test media the edge is significantly damaged. I for one am not particularly interested in how well my knife can cut after the edge has been significantly damaged, I'm more interested in how well it can hold a keen edge in lighter workloads. If the results in plain card stock mirror that of the silica imbedded material then it allows for the CATRA results to be taken with a much smaller grain of salt. (I'm especially interested in the lower alloy and low carbide content stainless steels, i.e. 52100, AEB-L, O1, A2, 1095, versus a fairly common and well respected higher carbide content steel like S30V.)
Click to expand...
The comparison I did between rope cutting tests and CATRA results gave me a lot more confidence in the CATRA providing relevant results. However, we can still expect some small differences with different test media or types of cutting. I have some rope of appropriate size that fits into the machine and hope to test it in the coming months.
 
This is the most impressive knife related investigation anywhere out there. The toughness/wear resistance balance puts this all in perspective. Thank you so much for the time and money investment to make this happen.
 
Thank you again Larrin for such reliable in depth study. Like other folks I'm more interested in AEB-L type steels for kitchen knives, and did find it interesting that 14C28N seemed to outperform AEB-L a bit, but darn it's hard to get 14C28N compared to AEB-L. AEB-L is one of my favorites due to the lower cost compared to many other alloys.

At the very end of the article you mention: "I found little change in edge retention by using high temperature tempering (1000 vs 400°F) or by using cryo treatments, at least when either heat treatment results in similar hardness. "

Do I understand that to say if I've got 3 AEB-L blades that were HT'd the same except one was took from quench plates direct to tempering oven, 2nd was took from quench plates to freezer for a -5°F freeze treatment, then to tempering oven, and 3rd was took from quench plates to dry ice bath then to tempering oven. The tempering temperature for each blade would be chosen so all 3 blades ended up at same hardness (say 60Rc). Would the performance be expected to be about the same when used for kitchen knives? Assuming the geometry of all 3 blades are the same?

Larrin, please allow me to say THANK YOU for your efforts again.
 
Ken H> said:
Do I understand that to say if I've got 3 AEB-L blades that were HT'd the same except one was took from quench plates direct to tempering oven, 2nd was took from quench plates to freezer for a -5°F freeze treatment, then to tempering oven, and 3rd was took from quench plates to dry ice bath then to tempering oven. The tempering temperature for each blade would be chosen so all 3 blades ended up at same hardness (say 60Rc). Would the performance be expected to be about the same when used for kitchen knives? Assuming the geometry of all 3 blades are the same?
Click to expand...
In this test they would be the same. Yield strength (different than hardness) and toughness may have some differences.
 
So good! Suchggood data, and I love a couple observations you make...

"It is a mistake to look only at edge retention for steel choice. For one thing, steel is not even the greatest controlling factor for edge retention. After all, sharpening in terms of grit finish and edge angle have a greater effect on performance than steel choice"

"... with higher toughness, the knives are better able to handle thin, low angle edges without chipping. And they can be heat treated to higher hardness to help prevent edge rolling and deformation, while still maintaining good toughness. This means that, indirectly, higher toughness can lead to better cutting performance because of the possibility of thinner edges."
 
razor-edge-knives said:
So good! Suchggood data, and I love a couple observations you make...

"It is a mistake to look only at edge retention for steel choice. For one thing, steel is not even the greatest controlling factor for edge retention. After all, sharpening in terms of grit finish and edge angle have a greater effect on performance than steel choice"

"... with higher toughness, the knives are better able to handle thin, low angle edges without chipping. And they can be heat treated to higher hardness to help prevent edge rolling and deformation, while still maintaining good toughness. This means that, indirectly, higher toughness can lead to better cutting performance because of the possibility of thinner edges."
Click to expand...

I asked about this on Patreon, and Larrin reminded me he has formulas posted to calculate edge retention based on carbide volume, geometry, and hardness. This is probably why AEB-l seems to hold an edge much better than the carbide volume suggests, better than the CARTA data suggests. Same with z-wear and V4e. They can be ground like a kitchen knife and used for edc. M4 isn’t used much by me, but I know others grind it very thin too. 3v loses too much toughness at the hardnesses needed for those super fine edges. (In my experience, anyway.) I think this is why W2, 52100, and Hitachi steels hold an edge so well in the kitchen.
 
CallumRD1 said:
That was a fascinating read. As you mention at one point in the article, it would be very interesting to test a subset of these steels on something like card stock with no silica impregnation. I'm curious to see how results differ in this less aggressive test media as you've previously shown that even after just a single stroke through the silica test media the edge is significantly damaged. I for one am not particularly interested in how well my knife can cut after the edge has been significantly damaged, I'm more interested in how well it can hold a keen edge in lighter workloads. If the results in plain card stock mirror that of the silica imbedded material then it allows for the CATRA results to be taken with a much smaller grain of salt. (I'm especially interested in the lower alloy and low carbide content stainless steels, i.e. 52100, AEB-L, O1, A2, 1095, versus a fairly common and well respected higher carbide content steel like S30V.)
Click to expand...

I too am curious about this.
 
Larrin, I have noticed that I can hand sand s35vn with moderate effort, but find z-wear nearly impossible to hand sand. Is this due to my abrasives being more able to cut the chromium carbides than vanadium carbides? I notice the same thing with Vanax. Quite difficult to hand sand.
 
Willie71 said:
Larrin, I have noticed that I can hand sand s35vn with moderate effort, but find z-wear nearly impossible to hand sand. Is this due to my abrasives being more able to cut the chromium carbides than vanadium carbides? I notice the same thing with Vanax. Quite difficult to hand sand.
Click to expand...
Difficulty in hand sanding seems to be directly tied to the amount of vanadium carbide and the hardness of the matrix.
 
This is so awesome Larrin. This is a huge benefit to our community. I hope to be back to work soon and be able to contribute.

I would love to see steels in the Z-Wear to M4 spectrum tested in hardness ranges of 64-66Rc. From my very limited use the seem to be able to handle that just fine. I realize that everyone wants to have their pet steels tested with their own special recipe though. Hopefully we can keep you funded well enough to continue this research. Thanks again for this huge amount of research and having it openly gifted to all of us.
 
Storm W said:
This is so awesome Larrin. This is a huge benefit to our community. I hope to be back to work soon and be able to contribute.

I would love to see steels in the Z-Wear to M4 spectrum tested in hardness ranges of 64-66Rc. From my very limited use the seem to be able to handle that just fine. I realize that everyone wants to have their pet steels tested with their own special recipe though. Hopefully we can keep you funded well enough to continue this research. Thanks again for this huge amount of research and having it openly gifted to all of us.
Click to expand...
You can estimate the effects of hardness using the 15.8 mm/Rc trendlines. The real values will be somewhat different but it will get you in the ballpark.
 
A8 mod looks a lot more impressive now. I will be using more of that too.

edit: I didn’t think much of it before, as it was not advertised as having much, if any edge retention. It has 3v levels of toughness, and wear resistance better than most of the simple steels. I could see hunters up here really liking it.
 
Last edited:
You must log in or register to reply here.
Back
Top