Introduction
Silicon steel sheet, known as electrical steel or silicon electrical steel, is a common material used in the manufacture of electrical equipment and electronic components. The different property and function of silicon steel sheet decide that different levels of silicon steel sheet be used in different equipment or devices. So it is necessary and important to establish a recognizable and uniform grading system for silicon steel sheet to ensure the reliability of various equipment or components made of silicon steel sheet.
In China and Japan, different countries use different grading systems for silicon steel sheet. This article will explain the properties and characteristics of silicon steel sheet from both China and Japan, and illustrate how manufacturers in these two countries designate grades for their steel sheets.
Characteristics of silicon steel sheet
Silicon steel sheet is an iron alloy with small amount of Si and other elements like Cr, Mn and Cu added. And it is based on the low-carbon steel by adding the silicon. With related process technical, silicon steel can receive high permeability and low-coercivity. Low-coercive force silicon steel is divided into ordinary silicon steel and high magnetic induction silicon steel according to its magnetic induction intensity, which meets the requirements of various electrical equipment and electronic components.
The features of silicon steel are largely determined by its silicon content. The higher the Si content, the higher the magnetic resistivity, permeability, maximum induction, and lower coercive force. On the other hand, the higher the Si content, the lower the mechanical properties of silicon steel, like tensile strength, yield strength and elongation.
In general, silicon steel sheet is grey and has a smooth, polished surface. It generally has a thickness of 0.1-8mm, and a width of 410-1300mm. Its density is 7.68-7.82 g/cm, and its bend strength is 0.252 N/mm.
China Grading System of Silicon Steel Sheet
In China, silicon steel sheet is divided into M27(0.27%), M36(0.35%), M45(0.45%), M30(0.30%) and M800 grades according to its magnetic properties. Among them, M36 grade silicon steel is the most commonly used silicon steel in China.
M27 is the lowest grade of magnetic properties in the characteristics of Chinese silicon steel sheet. The magnetic induction degree is 2800-30 W/kg, the maximum induction degree is 1.2T and the residual magnetic induction degree is 1.1T after 1000Oe magnetic field. This grade of silicon steel sheet is mainly used for making large power transformers, silicone steel electrical motors and silicon steel transformer cores.
M36 grade has higher magnetic properties than M27 grade. The magnetic induction degree is 3100W/kg, the maximum induction degree is 1.4T and the residual magnetic induction degree is 1.17T after 1000Oe magnetic field. Generally, M36 grade is used for making small and medium-sized transformers, motors, generators and other electrical equipment.
M45 grade has better magnetic properties than M36 grade. The magnetic induction degree is 3300-3500W/kg, the maximum induction degree is 1.5T and the residual magnetic induction degree is 1.2T after 1000Oe magnetic field. Generally, M45 grade silicon steel sheet is used for making high quality electrical motors and large transformers.
M30 grade has the highest magnetic properties among the five grades. Its magnetic induction degree is 3400-3700W/kg, the maximum induction degree is 1.7T and the residual magnetic induction degree is 1.42T after 1000Oe magnetic field. M30 grade silicon steel sheet is mostly used for making high quality electrical motors, medium and high voltage transformers and other motor cores.
M800 grade is a special grade silicon steel sheet. It is specially used for making silicon controlled rectifiers, semi-conductor appliances, power modules and other electrical equipment.
Japan Grading system of Silicon Steel Sheet
In Japan, 43, 50, and 55 grades are three grades of silicon steel sheet commonly used in the the market. These three types of silicon steel sheet can be divided at different properties.
43 grade is the lowest grade among the three Japanese silicon steel sheets. The highest induction magnetic field can reach 1.8T, the induced magnetic field is approximately 1.2T in normal working, and the magnetic flux density must not exceed 1.2T. The permeability of this grade of silicon steel sheet is 100-200.
50 grade has better magnetic properties than 43 grade. The magnetic induction degree can reach 2.6T and the permeability is 200-400. Generally, this grade silicon steel sheet is used to make small and medium power transformers and other electrical equipment.
The magnetic properties of 55 grade are the best among the three grades. The magnetic induction degree can reach 3T and the permeability is 300-500. This grade of silicon steel sheet is used to produce AC first armature winding, DC field winding and shunt weighing coil.
Conclusion
The grades structure of silicon steel sheet in China and Japan are different, as they used different grading systems. In China, five grades of silicon steel sheet are used, which are M27, M36, M45, M30 and M800. In Japan, three grades of silicon steel sheet are used, which are 43, 50, and 55 grades.
In conclusion, it is important for manufacturers to understand the properties of different grades of silicon steel sheet to make sure that the right grade of silicon steel sheet is used for the specific application.
