Choosing the right knife steel
When choosing the steel and its hardness for a knife, it is important to bear in mind the application for which the knife will be used. The demands on the steel for a hunting knife, for instance, are very different from those made on the steel for a marine fishing knife.
Sandvik can help you in the process of choosing the steel and the heat treatment to suit the application for which the knife is intended. The recommendations for selection of steel grade and hardening program are based on the combined requirements for edge performance, toughness and corrosion resistance.
Edge performance consists of three elements: sharpness, edge stability and wear resistance.
The ability of the steel to support a keen edge with razor sharpness. It also means that the knife will be easy to resharpen. This is important for all knives.
The ability for the knife edge to withstand edge rolling and edge micro-chipping. Rolled edges and micro-chipped edges are the most common reasons for resharpening. This is important for all knives.
The ability for the edge to resist abrasive wear. This is usually secondary to edge stability issues, such as micro-chipping or edge rolling.
Toughness is the resistance of the knife to cracking. Cracks always start at a weak point in the steel, such as an inclusion or a large primary carbide. So toughness is enhanced by a homogeneous structure that is free from impurities and large carbides. A fine-carbide steel grade will always have higher toughness than a coarse-carbide grade with a given hardness. Toughness is vital for professional and military knives.
Corrosion resistance should be selected to suit the application. Since high corrosion resistance involves sacrifices in edge performance, the best approach is to have corrosion resistance that is 'good enough' for the selected type of knife. An everyday carry knife and a fishing knife will make very different demands on corrosion resistance.