420HC stainless steel is a hard, high-carbon (HC) steel alloy that has high corrosion resistance. Depending on the intended use, 420HC steel is either annealed or tempered in the final step of manufacturing.
The hardness of steel is usually measured on the Rockwell C scale. Annealing 420HC stainless steel tends to result in a harder, more flexible metal compared to tempering. Tempering results in a tougher, more ductile steel. In general, because of its great edge-holding capabilities, ease of cleaning and relative hardness, 420HC stainless steel is used extensively for knife blades, surgical equipment, metal valves and large sheer cutting-edges.