Silicon steel is a silicon iron alloy with a silicon content of about 3%. Silicon steel sheets are widely used in mid to low frequency transformers and motor cores. The characteristic of silicon steel is that it has a higher full magnetic induction intensity (above 2.0T) than commonly used soft magnetic materials, so it can be used as a transformer core at high operating points (such as an operating magnetic induction value of 1.5T). However, silicon steel also has greater iron loss in commonly used soft magnetic materials. In order to avoid the iron core from overheating due to excessive loss, its operating frequency is not high, generally only below 20KHz, and it is mainly used in power frequency transformers.

Silicon steel is usually in the form of thin sheets to reduce eddy current losses in transformer cores. Nowadays, silicon steel sheets are mainly divided into two categories: hot-rolled and cold-rolled. Hot rolled silicon steel refers to the process of heating and rolling silicon steel plates above 850 ℃, followed by annealing. Due to the high rolling temperature, the rolled silicon steel sheets are isotropic, which means that 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 the stator and rotor of motors. Because to make the stator and rotor of the motor, circular parts need to be stamped on large silicon steel sheets. At this time, it is always expected that the silicon steel sheets will have magnetic properties along the circumferential direction, so non oriented silicon steel should be used.

In order to achieve better magnetic properties, people later invented cold-rolled silicon steel sheets, which are rolled at lower temperatures and then annealed. Cold rolled oriented silicon steel sheets are representative among them. Cold rolled oriented silicon steel sheets primarily undergo cold rolling on the slab, causing many structural defects to occur inside the material. During the subsequent annealing process, the material undergoes structural changes (known as recrystallization), which result in excellent magnetic properties of the silicon steel sheet in a certain direction. This means that the magnetic properties are related to the direction, hence it is called oriented silicon steel. After all, when used, allowing the magnetic lines in the iron core to pass in the direction of better magnetic function can maximize the magnetic potential of silicon steel sheets. For example, in a transformer, the magnetic field lines of the iron core material pass in one direction. If the silicon steel sheet is properly cut and then wound into the iron core, so that the circumferential direction of the iron core is exactly the direction where the magnetic function of the silicon steel sheet is better, then the magnetic permeability of the iron core will be very high, simple magnetization, and energy loss will be small, after all, it will increase the power of the transformer.

Article source: Transformer silicon steel sheethttp://www.cheungshun.com/