Electrical steel also known as Silicon Steel is used in a variety of applications ranging from transformer cores, generators and motors to magnetic cores and electrical components. Electrical steel is a thin steel sheet which contains a small percentage of silicon, normally between 0.005% and 0.2%. This makes it possible to achieve the desired properties including high magnetic flux density, permeability, electrical resistivity and superior mechanical properties.
Electrical steel is made using either the hot or cold rolling process and it is often referred to as electro-magnetic steel, silicon steel or permalloy because it has a higher magnetic flux density than common carbon steels. Electrical steel can be either in the annealed or grain-oriented state and the exact chemical composition and mechanical properties depend on the application for which it is intended. A common application for electrical steel is in electrical motors, transformer cores, generator cores and cores in other electrical equipment.
When electrical steel is sold in a grain-oriented form, the crystalline grain structure has been aligned so that most of the grains are parallel. This helps to concentrate the magnetic field into one axis and increases the permeability and efficiency of the steel. Grain-oriented electrical steel is made by cold rolling the steel several times in different directions until the grain structure is at an optimal level. This is done using a special tempering process, which is also known as grain-orientation.
The magnetic properties of electrical steel are enhanced by annealing, a heat treating process. During annealing, the steel is heated to a very high temperature and cooled slowly. This reduces the content of residual and strain stresses within the steel, which are responsible for inhomogeneities in the grain structure and distortion of the crystalline lattice.
Electrical steels are produced in a number of grades and thicknesses. The grade usually defines the electrical properties of the steel, such as the saturation magnetic flux density, DC resistivity and core loss. The thickness of the electrical steel is also important in determining the suitability for various applications. The thicker the electrical steel is, the more powerful an electrical component it can be used for.
In many applications, a well-oriented electrical steel is more efficient than steel which is not oriented and has no grain structure. Electron microscopy can be used to determine the degree of orientation and the effectiveness of the magnetic field.
Electrical steel is a key component of devices and machines which use electromagnetism. It can be used in the core of generators, motors, transformers, solenoids and many other devices. It is also used in electric vehicles and hybrid cells as a magnetic core material.
