Crystallization of Steel
Crystallization of steel is an integral part of the steelmaking process. Steel makers produce the steel they require by forming a molten product of iron ore, recycled steel, or iron alloy and adjusting the conditions to obtain the desired properties of the particular steel. The crystallization of the steel is an important part of the cooling process and the properties it affects, such as ductility and tensile strength.
When compared to other forms of steel crystallization, the most broadly accepted type of steel crystallization is the process of solidification. Solidification is the process of molecules forming into their respective atoms and then becoming solid as a complete structure. During this process, large molecules of metallic elements break down into smaller molecules and eventually into atoms of metallic elements. It is these atoms that unite and form the crystalline structure of the steel. As the structure of the steel is formed, the atoms create planes of lattice that are of the same size and shape and have an oxygen atom at the center of each lattice.
The type of crystals created in the steel depends on the heat treatment that is used as well as the rate of cooling. It is possible to create different types of crystals by rapid cooling, or quenching, and annealing the steel. Quenching refers to a cooling process done quickly which keeps the solid structure of the steel in an austentitic form. It essentially freezes the molecules in place, making the steel very strong and brittle.
An annealing process, on the other hand, is a slower cooling procedure and results in a more ductile metal. Steel is annealed by slowly cooling it, causing the atoms to adjust and form larger, more dispersed type crystals. This process increases the metal’s ductility and allows for it to be worked into shapes.
Steel crystallization is an essential part of the steelmaking process, as it affects the properties of the metal. The method of cooling the molten steel must be chosen carefully and the rate of cooling adjusted appropriately in order to achieve the desired properties of the particular steel. Although different types of crystallization can affect the properties of steel, solidification is the most common and widely accepted form of steel crystallization.
