PROCESS FOR PRODUCTING ULTRAHIGH SILICON ELECTRICAL THIN STEEL SHEET BY COLD ROLLING

摘要

The present invention provides a thin sheet product having a combination of excellent magnetic properties inherent in the steel having a silicon content of 6.5% or near 6.5% with a further lowered iron loss property, particularly in a high frequency region, through the production of a magnetic thin steel sheet having a thickness of 0.23 mm or less by cold-rolling a steel sheet comprising by weight not more than that 0.006% of carbon, 5.0 to 7.1% of silicon, 0.07 to 0.30% of manganese, not more than 0.007% of sulfur, 0.006 to 0.038% of acid soluble aluminum and 8 to 30 ppm of total nitrogen with the balance consisting of iron and unavoidable impurities at a sheet temperature in the range of from 120 to 350 DEG C optionally after annealing the sheet at a temperature in the range of from 750 to 1020 DEG C, and annealing the cold-rolled sheet at a temperature in the range of from 800 to 1020 DEG C for recrystallization and grain growth, to thereby prepare a magnetic steel sheet having a small thickness of 0.23 mm or less. IMAGE