What is the best blade steel?
This is a tricky question because there is no best steel for every application. Some will be great for one task while being horrible at another. The same goes for blade shape. A Tanto may be great for piercing a door but will be horrible for filleting fish (I've filleted many fluke with a Titanium Tanto Kwaiken that Alfa Knife made me some 5 years ago now).
Some great blade steels that I like are
Tool Steel - CPM, A2, O1, D2
Stainless Steels - 440C, 154CM, CPM154, CPMS-30V, CPMS-35VN, CPMS-90V
High Carbon Steels - 15N20, CPM REX M4, 1095, 5160
A good Blade is a sliding matrix of Hardness, Corrosion Resistance, Edge Retention, Toughness, Ease of Sharpening, and Wear Resistance.
- Very hard steel (e.g. chisels, quality knife blades): HRC 55–66 (Hardened High Speed Carbon and Tool Steels such as M2, W2, O1, CPM-M4, and D2, as well as many of the newer powder metallurgy Stainless Steels such as S30V, CPM-154, ZDP-189, etc.)
- Axes: about HRC 45–55
- Brass: HRB 55 (Low brass, UNS C24000, H01 Temper) to HRB 93 (Cartridge Brass, UNS C26000 (260 Brass), H10 Temper)