I believe SPY27 is proprietary to Spyderco.
Here is Larrin’s write up on it if you are interested.
https://knifesteelnerds.com/2020/01/15/spyderco-exclusive-cpm-spy27-steel-analysis/
JonesE
I like the idea of the exotic steels with special properties, but it all goes way over my head!
I tried to understand a bit about how it all works when the company that makes Magnacut was in financial trouble, but I still don’t really know if the Arc will still be Magnacut, if it’ll be the same steel with a different brand name, or if it’ll change to another steel altogether.
From a personal perspective, I’m happy all this research and development is happening, but I’m not going to pretend I really know what mixture of hardness, corrosion resistance, durability, and edge retention is best for me