process for producing a steel sheet, a secondary récristallisation grains of cubic texture

摘要

A method of producing a cube-oriented silicon steel sheet having a good orientation and low iron core loss comprises providing an intermediate gauge silicon steel sheet containing 2.0-4.0% silicon, 0.010-0.045% acid soluble aluminium and the rest iron and consisting of recrystallization grains in the (100) [001] orientation, said acid-soluble aluminium consisting of more than 5% aluminium nitride, cold rolling said intermediate gauge silicon steel sheet in a direction substantially parallel to the [001] direction to reduce the thickness by 50-80%, and thereafter subjecting the thus cold rolled steel sheet to an anneal at a temperature in the range of 1000-1300 DEG C. in a neutral or reducing atmosphere. The intermediate gauge silicon steel sheet is prepared from a hot rolled silicon steel stock containing 2-4% silicon and 0.010-0.050% aluminium by cold rolling the stock in one direction with a reduction of 30 to 60% in thickness, cold rolling in the other crossing direction thereto within a deviation of sB20 DEG with a reduction of 20 to 50% in thickness and thereafter subjecting the rolled sheet to a decarburizing anneal within a temperature range of 850-1200 DEG C. for a period of 10 minutes followed by an intermediate anneal in an atmosphere of H2 containing 50% N2 at the maximum holding temperature of 1150 DEG C. The intermediate gauge sheet is cold rolled in the [001] direction with a reduction of 72% to the final gauge and finally subjected to a box anneal at the highest holding temperature of 1200 DEG C. for a period of 20 hours in a neutral or reducing atmosphere. Specific examples of the method are given in the Specification. Specification 930,497 is referred to.