History of electrical steel

Development stage of hot-rolled silicon steel (1882~1955)

The magnetic permeability of iron is thousands to tens of thousands of times higher than that of air, and the magnetic flux density is high when the iron core is magnetized, which can generate a magnetic field much stronger than the external magnetic field. Ordinary hot-rolled low-carbon steel plate is the earliest iron core soft magnetic material used in industry.

In 1886, the Westinghouse Electric Company of the United States first used hot-rolled low-carbon steel plates with an impurity content of about 100% to make transformer laminated iron cores.

In 1890, thick hot-rolled low-carbon steel sheets were widely used to manufacture motor and transformer cores. However, due to the low resistivity of low-carbon steel, the core loss is large: the content of carbon and nitrogen is high, and the magnetic aging is serious.

In 1882, Hadfield, England began to study silicon steel.

Magnetic results of %Si-Fe alloys were published in 1898.

In 1903, the United States obtained the right to use the Hadfield patent. In the same year, the United States and Germany began to produce hot-rolled silicon steel sheets.

In 1905, the United States had mass-produced it. In a short period of time, it has completely replaced ordinary hot-rolled low-carbon steel plates to manufacture motors and transformers, and its iron loss is more than half lower than that of ordinary low-carbon steel.

During the period from 1906 to 1930, the production plant and the user had a unified understanding of the cost of hot-rolled silicon steel sheets, mechanical properties, and reforms in the design and manufacture of motors and transformers, improving product quality and increasing production.

Development stage of cold-rolled electrical steel (1930~1967)

This stage is mainly the development stage of cold-rolled ordinary grain-oriented silicon steel (GO) sheet.

In 1930, Goss of the United States began to conduct a large number of experiments by using cold rolling and annealing methods to explore the manufacturing process of oriented silicon steel coils in which the easy magnetization direction <001> of the grains is arranged parallel to the rolling direction.

In 1933, Gauss used two cold rolling and annealing methods to produce 3% Si steel with high magnetic properties along the rolling direction. In 1934, he applied for a patent and published it publicly.

In 1935, Armco Steel Company cooperated with Westinghouse Electric Company to produce according to Goss patented technology. Afterwards, Armco Steel Company adopted technologies such as rapid analysis of trace carbon and continuous improvement of manufacturing processes and equipment to gradually improve product quality.

In 1958, after mastering the two pre-process manufacturing processes of MnS inhibitor and slab high-temperature heating, the patented technology for manufacturing oriented silicon steel has been basically perfected, and the magnetic properties of the product have been greatly improved and stabilized.

In 1959, 0.30mm thick products were produced, and in 1963, 0.27mm products were produced.

In the early 1940s, Armco Steel Company began to produce cold-rolled non-oriented silicon steel sheets.

From 1963 to 1967, the United Kingdom, Japan and other countries stopped producing hot-rolled silicon steel sheets. Hot-rolled silicon steel sheets are gradually replaced by cold-rolled non-oriented electrical steel and cold-rolled oriented silicon steel sheets.

Development stage of high magnetic induction grain-oriented silicon steel (1961~1994)

In 1961, based on the introduction of Armco patents, Nippon Steel first trial-produced high magnetic induction grain-oriented silicon steel with AIN+MnS comprehensive inhibitors.

Trial production began in 1964 and was named Hi-B, but the magnetic properties were not stable. After 15 years of continuous improvement, the manufacturing process of Hi-B steel has been perfected day by day, and the Z8H grade was officially produced in 1968.

Since 1979, Nippon Steel and Kawasaki have successively produced new grades of .