Process for producing aluminum-bearing grain-oriented silicon steel strip

Abstract

A process for producing an aluminum-bearing grain-oriented silicon steel strip from a silicon steel slab containing up to 0.02% carbon, 0.01 to 0.1% aluminum, 2.7 to 4.0% silicon, and 0.002 to 0.02% nitrogen, the balance being iron and unavoidable impurities, said slab optionally containing at least one of 0.01 to 0.5% antimony and 0.01 to 1.0% copper, said process comprising: recrystallization hot rolling said slab, said rolling being commenced when said slab has a temperature up to 1,250.degree. C., and effected at a total reduction rate of at least 80% with a plurality of passes, including at least one pass having a reduction rate of at least 35%, before said steel has a temperature of 900.degree. C.; strain accumulation finish hot rolling said steel at a total reduction rate of at least 40% and at a steel temperature up to 900.degree. C.; annealing said hot rolled steel continuously at a temperature of 700.degree. C. to 950.degree. C.; cold rolling said steel; annealing said cold rolled steel continuously at a temperature of 700.degree. C. to 900.degree. C. for primary recrystallization; and finish annealing said steel, an atmosphere gas containing at least 30% of nitrogen being introduced during the heating step of said finish annealing when a temperature of 800.degree. C. to 1,000.degree. C. prevails.