METHOD FOR PRODUCING HIGH SILICON STEEL, AND SILICON STEEL

摘要

A method for the production by rolling of a silicon steel sheet having a silicon content of 3 wt.% or more and a sendust steel sheet, which comprises conducting a cold rolling by utilizing, as a material to be rolled, a sintered sheet or a quenched steel sheet having an average crystal grain diameter of 300 mu m or less or a sintered sheet derived from a powder obtained by blending a pure Fe powder and a Fe-Si powder in a specific ratio so that a Fe-rich phase remains in the sintered sheet. The production by rolling of such a high silicon steel sheet and a sendust steel sheet has been considered to be impossible hitherto. A method which further comprises adding, in advance, a non-magnetic metal element such as Ti is also disclosed, which results in allowing a Fe-rich phase and a Si-rich phase to easily form a solid solution and in promoting the growth of a crystal grain, to provide a silicon steel sheet having excellent magnetic properties. A method for producing a sendust steel sheet having excellent magnetic properties which comprises vapor-depositing aluminum on both the sides of this silicon steel sheet and then subjecting it to heat treatment, to thereby diffuse and penetrate the aluminum into the steel sheet and at the same time increase a crystal grain diameter.