METHOD FOR PRODUCTION OF HIGH-STRENGTH ELECTROTECHNICAL ISOTROPIC STEEL IN THE FORM OF A COLD-ROLLED STRIP Russian patent published in 2022 - IPC C21D8/12 C22C38/60 

FIELD: ferrous metallurgy.

SUBSTANCE: invention relates to ferrous metallurgy, namely to the production of electrical isotropic steel (EIS) of HF (high frequency) class in the form of a cold-rolled strip used for the manufacture of magnetic cores of high-frequency electric machines, in particular electric vehicle engines operating at high frequencies (400 Hz or more). Steel is smelted containing components at the following content, wt. %: carbon no more than 0.005, silicon 2.70-3.40, aluminum 0.70-1.30, manganese 0.10-0.30, antimony 0.007-0.04, phosphorus no more than 0.015, sulfur no more than 0.005, titanium no more than 0.005, nitrogen no more than 0.004, iron and the inevitable impurities the rest. Casting of steel into slabs, hot rolling of slabs to obtain a hot-rolled strip, heat treatment of a hot-rolled strip, etching, cold rolling to obtain a cold-rolled strip and its final annealing are carried out. Cold rolling is carried out in two stages with intermediate annealing between them, while the second stage of cold rolling is carried out with a degree of deformation of 40-65%. Intermediate and final annealing is carried out at a temperature of 900-930°C.

EFFECT: magnetic and mechanical properties of electrotechnical isotropic steel are improved.

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