| 摘要 |
1. A method of manufacturing isotropic electrical sheets, particularly designed for constructing magnetic housings of large spinning electric machines which consists in melting steel including 0.025-0.045 percent of carbon, 0.20-0.50 percent of manganese, 2.6-3.1 percent of silicon, 0.2-0.5 percent of aluminum and small quantities of other components occurring as impurities, and ingots made of the said steel are rolled into slabs, and further into hot-rolled sheet about 2.2 mm thick, which is further, after etching, cold-rolled in one or two stages until thickness between 0.35-0.50 mm is obtained, and annealed, characterized in that rolling of slabs into sheet is conducted in a temperature not exceeding 1,300 degrees C, and after the cold rolling is finished, decarburisation annealing is first conducted in continuous furnaces in humidified nitrogen-hydrogen atmosphere at a temperature between 800 and 900 degrees C. Further the sheet is coiled and the coils are annealed in a dry hydrogen or dry hydrogen-nitrogen atmosphere at a temperature between 950 and 1,150 degrees C, and then the sheet is subject to continuous flattening annealing at a temperature between 800 and 870 degrees C.
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