Silicon steels are essential magnetic materials used in many industries. This article primarily introduces the two main types of silicon steels: non-oriented silicon steel and oriented silicon steel.
Definition of Silicon Steels
It is a low-carbon iron alloy with a silicon content ranging from 0.5% to 4.5%. Based on its structure and applications, it is classified into non-oriented silicon steel and oriented silicon steel. Silicon steel is produced through hot and cold rolling processes. Generally, sheets thinner than 1mm are silicon steel sheets. The addition of silicon increases the electrical resistivity and maximum magnetic permeability of iron and reduces core losses (iron loss), coercivity, and magnetic aging.
Classification of Silicon Steels Based on Magnetic Properties
It is an important soft magnetic material, which can be divided into two main categories—non-oriented silicon steel and oriented silicon steel—based on its magnetic properties and manufacturing processes.
| Oriented silicon steel has grains primarily aligned in one direction and contains a higher silicon content, mainly used in transformer manufacturing.
| Non-oriented silicon steel has a random grain distribution and a lower silicon content, primarily used in motor manufacturing.
Properties of Silicon Steels
| Oriented Silicon Steel: The magnetic properties exhibit strong directionality, with the lowest iron loss and highest permeability in the rolling direction, and high magnetic flux density under a certain magnetization field. The silicon content in oriented silicon steel is about 3%, and oriented silicon steel requires low levels of oxide inclusions in the steel, along with certain suppressants (such as MnS or AlN).
| Non-oriented Silicon Steel: This type has a silicon content of 0.8%-4.8%, rolled into sheets thinner than 1mm. The addition of silicon enhances the electrical resistivity and maximum magnetic permeability of iron while reducing coercivity, core losses (iron loss), and magnetic aging.
Cold-Rolled Silicon Steel Process
The production process has relatively low requirements, with silicon content ranging from 0.5% to 3.0%. The finished product thickness after cold rolling is generally 0.35mm and 0.5mm, with a higher magnetic flux density compared to oriented silicon steel, uniform thickness, high dimensional accuracy, and a smooth surface, improving the filling factor and material magnetic properties.
For cold-rolled oriented kind, the silicon content is over 3.0%, while the carbon content is in the range of 0.03%-0.05%. The steel must have low levels of oxide inclusions and require suppressants. Compared to cold-rolled non-oriented silicon steel, oriented silicon steel has lower iron loss, strong directional magnetism, and superior high permeability and low loss characteristics in its rolling direction. Cold-rolled oriented silicon steel is also known as cold-rolled transformer silicon steel, primarily used for transformer manufacturing.
Cold-rolled oriented silicon steel can be further categorized into standard-oriented silicon steel (CGO) and high magnetic flux-oriented silicon steel (Hi-B). Oriented silicon steel consist of single-oriented steel strips, mainly used for manufacturing various electromagnetic components such as choke coils and transformers in electronic instruments.
Silicon Steels and Permanent Magnets
| Motors: From the perspective of power density, the combination of the silicon steels and neodymium magnets allows motors to output greater power in a smaller volume. For example, in the drive motors of electric vehicles, using a combination of the two materials can meet the power demands of the vehicle within limited space and help improve the vehicle’s range.
| Transformers: Silicon steels are the primary material for transformer cores, known for its good magnetic conductivity. When paired with permanent magnets in certain specialized transformer designs, such as in some miniaturized and high-efficiency power transformers, permanent magnets can assist in stabilizing the magnetic field and reducing eddy current losses and hysteresis losses in the steel core.
Applications of Silicon Steel
Non-oriented Silicon Steel
| Large Electromechanical: Water, thermal, and nuclear power units over 300,000-500,000 watts, wind power units
| Household Appliances: Used in high-efficiency variable frequency air conditioning compressors and high-efficiency variable frequency refrigerator compressors
| New Energy Vehicles: Drive motors and micro motors in new energy vehicles.
Oriented Silicon Steel
750KV and 1000KV High-end transformers
220-500KV and 110-200KV medium-low-end transformers
Magnet Manufacturer
At Tengye, we’re thrilled to be early participants in your new projects. Our passion for magnets extends from material selection and design optimization to providing magnetic solutions. We hope to bring our knowledge and experience to the forefront by actively engaging in your upcoming projects. Work with our magnet experts to get the right magnet solution.
Image Source: Electrical4u & Hal & Mdpi & Nipponkinzoku & Mrssteel & Paftamuhendislik & Poscomaharashtra
