Elmax is a steel made by Böhler Uddeholm and consists of:
Spyderco also refers to Elmax as Elmax PM 170 in their Edge-U-Cation page.
Some information from the Böhler Uddeholm website:
Uddeholm Elmax is a high chromium-vanadium-molybdenum-alloyed steel with the following characteristics:
• High wear resistance
• High compressive strength
• Corrosion resistant
• Very good dimensional stability
High wear resistance is normally connected to low corrosion resistance and vice versa. In Uddeholm Elmax it has however been able to achieve this unique combination of properties by a powder-metallurgy-based production.
A PDF is also available from Böhler Uddeholm with additional data.
Some information from the Spyderco website:
Böhler first sold steel in North America in 1925 by providing European-made steels to toolmakers, manufacturing industries and construction jobs in the U.S. Their Elmax is an alloy composed using powdered metallurgic technology that was designed specifically for high-tech applications, primarily for use in the electronics industry. It contains elevated levels of chromium, vanadium-molybdenum that deem it a well-tailored fit for making knife blades. These elements translate into resistance to wear and corrosion and it has a homogenous grain structure making it malleable when grinding and forming.