440C Stainless Steel for Knife Blades
AISI 440C Stainless Steel
440C is a tough and relatively corrosion resistant martensitic stainless steel that maintains a good edge. For many years, 440C was the benchmark cutlery steel, and even today, represents an excellent choice for knifemaking that would fit most people's requirements. Its characteristics in general however do make it inferior to 154CM in most ways including corrosion resistance, wear resistance, hardenability and edge holding.
The microstructure of 440C is not as fine and uniform as 154CM, which results it the steel not taking as fine an edge, and can cause some chipping as well. It is still used by many knifemakers because it is easier to work with than 154CM or any of the other super steels, and as some claim, can perform even better with a Cryo or Dry Ice Quench. 440C can be hardened to about RC60 in use.
Some makers using 440C extensively include Swiss company Klotzli and Canadian custom knifemaker George Tichbourne. 440C belongs to the family of stainless steels that include 440A and 440B, the major differences being the variance in carbon content.