Silicon steel is a ferrosilicon alloy with about 3% silicon content. Silicon steel sheets are widely used in medium and low frequency transformers and motor cores. Silicon steel is characterized by the highest saturated magnetic induction (above 2.0T) in common soft magnetic materials, so it can be used as transformer core at high operating points (such as 1.5T). However, the iron loss of silicon steel is also the largest among the commonly used soft magnetic materials. In order to avoid the iron core heating due to excessive loss, its application frequency is not high. It can only operate below 20 KHz, and is mainly used in power frequency transformers.

Silicon steel is usually thin, which is to reduce the eddy current loss of transformer core. At present, silicon steel sheets are mainly divided into hot rolling and cold rolling. Hot-rolled silicon steel is the process of rolling the slab of silicon steel after heating at above 850 C, and then annealing. Because of the high rolling temperature, the rolled silicon steel sheets are isotropic, that is to say, the magnetic properties of the silicon steel sheets are the same in all directions. This isotropic silicon steel is also called non-oriented silicon steel. Non-oriented silicon steel is widely used in stators or rotors of motors. Because to make the stator and rotor of the motor, it is necessary to punch out the round parts on the large silicon steel sheet. At this time, it is always expected that the silicon steel sheets will have the same magnetic properties along the circumference, so non-oriented silicon steel should be used.