In this article you will find the basic division of steels for the production of knives in terms of steel composition.
We will also explain what they mean and how their individual components affect steel. Finally, you will become familiar with the basic concepts that you may encounter within the framework of steels.
We basically divide knife steel into three parts
Basically, all steel contains carbon. However, carbon steels contain more carbon, which is also reflected in their properties. They generally have better cutting properties, are easier to process and also grind. A big advantage is that these steels can be forged, so you get a strong and durable edge and the rest of the blade is flexible. However, the disadvantage is that they are more susceptible to corrosion, so they require more maintenance.
Even stainless steels are not completely corrosion-resistant and, as with carbon steel, the name is rather helpful. Stainless steels include those with a chromium content of 12% or more, which makes them resistant to corrosion. In general, stainless steels are easier to dull and harder to grind than carbon steels, and are also more expensive. However, they require less maintenance in terms of susceptibility to corrosion.
Damascus steels are a special kind of steels that are made up of several types of steels. These are usually connected together using a blacksmith's weld. Damascus steel is very well known not only for its properties, but also for its design. The basic drawing is determined by the passage of the weld that divides the boundaries between the steel. However, it is possible to make the drawing the same as the steel itself and modify it by combining blacksmith welding together with other blacksmithing techniques.
For each of the steels we offer, you will find a so-called steel data sheet . That's basically the description of steel. It contains quenching and tempering temperatures and other information about the given material. The chemical composition of the steel is also listed here. The property of individual steels can be read from it.
Let's now explain what they mean and how the individual chemical elements contained in steel affect steel.
- steel is an alloy of iron with carbon, which must be at least 0.3% in volume in order for the steel to be hardenable.
- additional (alloying) elements also contribute to the hardenability of steel.
- high-carbon steels contain more than 0.5% carbon, and as the carbon content (C) increases, the hardness of the steel increases to approx. 60 to 62 HRC.
Individual chemical components of steels
- Cr - chromium - determines the alloy's corrosion resistance, wear resistance and hardenability; but higher Cr contents increase brittleness with increasing hardness. From 12%Cr in the steel, it starts to be corrosion-resistant. The more Cr, the higher the corrosion resistance, but the absolute stainless property is not!
- Mn - manganese - softens the degree of grain fineness, contributes to hardenability, strength and wear resistance, has a deoxidizing effect during heat treatment and rolling; is the content of many knife steels.
- Mo - molybdenum - forms carbides, prevents brittleness and enables high strength at elevated temperatures, is added to many air-hardenable steels, generally increases strength, hardness, hardenability and toughness; positively influences machinability and corrosion resistance.
- Ni - nickel - is involved in strength, corrosion resistance and, above all, toughness.
- Si - silicon - increases strength and wear resistance and, like Mn, makes machining more difficult.
- W - tungsten - increases wear resistance and, together with Cr or Mo, participates in the development of high-speed steels, the so-called Hi speed steels.
- V - vanadium - determines the shape and mainly the fineness of the carbides, which creates abrasive resistance, toughness and hardenability; it is contained in a large number of steels.
- Co - cobalt - increases strength, hardness, allows cooling from higher temperatures, participates in the properties of the material in cooperation with other alloying elements.
Other terms that we may come across in the case of steels are hardening, tempering and hardness.
- Hardening - is a method of heat treatment of steel. During it, the steel is heated to the so-called quenching temperature, and then it cools sharply. This gives it better mechanical and physical properties. In the case of steel, a supersaturated solid solution of carbon in iron (so-called martensite) is formed. It is characterized by a fine structure. We harden in order to achieve a higher or maximum hardness of the product or its working surface, for example an edge. The hardened component has a higher hardness, but loses its toughness and therefore becomes more brittle.
- Tempering - is a heat treatment of steel, during which its properties are affected by appropriate heating, in particular, internal stress after previous hardening is removed. Steel almost always softens after hardening. It is performed by slowly heating the material to the so-called tempering temperature, which is lower than the temperature of the critical point, i.e. without phase and structural transformations. It is usually carried out in so-called tempering furnaces.
- Hardness - is a mechanical property of the material, expressing the resistance against penetration of the test body into the surface. It is measured by devices called durometers. Most often, hardness is expressed by a number. HRC is a Rockwell hardness test that belongs to the static material hardness tests. The method of its implementation is described and standardized by the ČSN EN ISO 6508-1 standard. Principle: the test body - the indenter - due to the precisely defined load penetrates the material being examined, while its hardness is determined from the degree of deformation of the surface of this material (the depth of the indentation of the test body is measured). The indenter is a diamond cone with an apex angle of 120°, in this case the test is carried out under a load of 1471 N.
All the steels we supply are in their raw, non-turbid state, and are not temperature-treated in any way! Unclouded steel can be machined, whereas clouded steel is already hard and brittle, and machining is difficult.
We believe that our basic division of steels has helped you, and that thanks to it you will decide on the right steel that will suit you best for your project.