Stainless steel knives: what should we look for when purchasing?

There are numerous items that are essential in different applications, but one of the most important tools that we cannot do without is a knife. They are necessary to perform daily activities, from the preparation of meals to opening packaging, home repairs, tourist trips, and gardening. To facilitate individual work, we can adjust the size and shape of the handle or blade, but one of their essential features is the knife steel. The material used must meet specified requirements in terms of its characteristics and allow obtaining the parameters required in a specific application. It applies to the typical knives used in the kitchen or workshop, carried by us and the special tools required for industry. We can take a closer look at the necessary features and check what to look for when choosing a knife.

What are the requirements for the steel used to manufacture knives?

Regardless of its intended use, every knife has a cutting edge at the interface of the forming surfaces. Depending on the tool’s application, it may run at different angles, but it is important to maintain the geometry for as long as possible. To achieve this goal, we are required to use a steel grade that is going to be sufficiently resistant to abrasion. Equally important is the hardness of the steel grade; it should be as high as possible since cutting does not cause material deformations, which affects both the durability of the knife and its cutting precision. Maintaining low brittleness, which could lead to premature breaking of the blade, is also highly significant. In many applications, metal elasticity is essential, as it allows the temporary deformation of the material, the reduction of the risk of irreversible deformation, and the restoration of the original shape after an interaction has ceased (which is usually a pressure on the blade’s side surface). One of the requirements in terms of resistance to external factors relates to the steel’s stainless properties. They are critical if the knife is frequently in contact with water or is exposed to high moisture. As far as the knife’s comfort of use is concerned, the ease of restoring the proper shape to the cutting edge, its sharpening, is vital.

What types of steel are selected for knives?

When selecting a proper steel for knives, we can chose one of the many popular grades with various properties that depend on the type of tool, the loads exerted on it, and primarily the type of material to be cut and the operating conditions. High-grade stainless steels are the ones that are used most frequently; they contain additives that improve the alloy’s mechanical properties and its resistance to chemical attack. Stainless steels are particularly popular. They contain an admixture of chromium that significantly reduces the susceptibility to corrosion and increases the hardenability. For this purpose, steel is additionally enriched with nickel, which, apart from rust prevention and hardenability, improves impact resistance. A frequent solution is to use steel containing molybdenum, as well as an additive of vanadium or tungsten, as these elements have a positive impact on the reduction of the susceptibility to abrasion. To produce knives, many manufacturers use classic tool steels and high-speed steels, including those produced using powder metallurgy. These are usually steels intended for cold work; in industrial applications, however, tool steels designed for hot work, mainly high-speed steels, may turn out to be essential. Another important parameter is the susceptibility to heat treatment and chemical treatment, e.g., carburising.