Method of manufacturing thin high magnetic flux density unidirectional electrical steel sheet with excellent product magnetic properties by single-stage cold rolling method

摘要

PURPOSE:To stably produce the grain-oriented silicon sheet by a single-stage cold rolling method by specifying the contents of N and acid-soluble Al in a silicon steel slab, thickness of a hot rolled plate, the content of N in the form of AlN in the hot rolled plate, and the hydration water content of MgO in a separation agent at annealing, respectively. CONSTITUTION:At the time of producing a thin grain-oriented silicon sheet from a slab of a silicon steel having a composition consisting of, by weight, 0.060-0.120% C, 2.9-4.5% Si, 0.050-0.090% Mn, 0.020-0.060% S and/or Se, 0.02-0.25% Sn, 0.0050-0.0100% N, {(27/14)XN%+0.0035} to {(27/14)XN%+0.0100}% acid soluble Al, and the balance Fe with inevitable impurities, hot rolling is carried out by regulating the thickness of hot rolled plate so that draft in cold rolling becomes 85-92% and also controlling the content of N in the form of AlN in the hot rolled plate to 0.0005-0.002%. Further, the hydration water content of MgO in a separation agent at annealing is controlled to 0.5-3.0%. By this method, the thin grain-oriented silicon sheet with high magnetic flux density excellent in magnetic properties of product can be stably produced by a single-stage cold rolling method.