Best bang for your buck steel for edge retention. D-2 is a semi non-stainless tool steel capable of holding a long time edge. Can be difficult to sharpen.
An outstanding knife steel, a high-carbon, high chrome tool steel which is often used for the steel cutting dies in every tool and die shop in the U.S.; with 1.40-1.60% Carbon, 0.70-1.20% Molybdenum, 11-13% Chromium and 1.10% Vanadium, D-2 can be hardened far beyond the favored 60-61 Rc. The first heavy user was Jimmy Lile; the strongest convert has been Bob Dozier. This air hardening steel takes a really good edge, and holds it. This steel has been recently made popular by the great results in the performance of D-2 heat-treated by Dozier - who gets verifiably better results than other makers/manufacturers. It is technically a non-stainless steel, despite a higher Chromium content than other non-stainless steels.