More Edge Retention Testing - Rex 45, Maxamet, SPY27, XHP, CPM-T15, 420, Rex 76

[Larrin]

A new set of edge retention tests on a range of high speed and stainless steels including Rex 45, Rex 76, CPM-T15, SPY27, XHP, and 420. We also did toughness tests on several of those steels that we had not yet been tested. And we redid our Rex 121 knife with a new heat treatment that was much easier to sharpen so it got a significantly higher score. https://knifesteelnerds.com/2021/05...eels-xhp-spy27-maxamet-rex-45-420-t15-rex-76/

 

[A.McPherson]

Interesting stuff, thanks Larrin!

 

[Rooster81]

Thanks for all your work Dr. Thomas!

Maybe I'm reading the reports incorrectly, but based on the Rex 45 scores it looks as though Rex 45 would perform similar to S30V, both have similar toughness and edge retention. However user reports and YouTube tests would seem to indicate Rex 45 is a "better" steel.

Does the added hardness on the Rex 45 make for better "edge stability"? Or is Rex 45 more prove to chipping?

Thanks for any replies.

 

[Larrin]

I can’t speak for every YouTube video. Most of them use some kind of edge retention test like cardboard or rope cutting and don’t test other properties as often. If the test they are doing involves edge deformation then that would favor the steel with higher hardness if they have equivalent wear resistance. I talked about this in relation to some rope cutting tests in my recent MagnaCut video:

 

[Mecha]

Nice article, Larrin!

"I was probably most impressed with Z-Max and Maxamet in terms of their combination of toughness, hardness, and edge retention they have, though of course still at the lower end of the toughness spectrum. Maybe there is something to putting “max” in the name for steel performance."

Got a good chortle out of that one. If I ever make a batch of special ti, clearly it should be named, "MaxxxTi Extreme" in order to secure best performance.