To make batter the magnetic properties of the subject steel sheet at a low cost by allowing it to contain a specified compsn. of. C, Mn, P and S, in which the contents of Si and Al satisfy the specified relations, and the balance Fe with inevitable impurities.
This steel sheet contains, by weight, ≤0.010% C, %h1.0% Mn, ≤0.1% p and ≤0.010% S. Then, the contents of Si and Al satisfy the relations of 1.8% ≤Si+Al≤5.0% and 0.7≤Al/Si≤1.4, respectively. The steel sheet can be produced by an ordinary method, and, e.g. molten steel refined to the above compsn. is formed into a slab by a continuous casting method, which is subjected to hot rolling and cold rolling to form into a cold rolled steel sheet, and next, continuous annealing is executed. The draft in the cold rolling is suitably controlled to 50 to 90%. In the continuous annealing, the treating temp. is made suitable so as to control the desirable average crystal grain size to 50 to 200 μm. In the case the content of Si+Al is about 4%, the conditions of 1020 to 1060°C and 5 to 20 sec are suitable.
HONJO NORIYUKI
YASHIKI HIROYOSHI
