Abstract: In the production of a grain-oriented electrical steel sheet, a slab (1) is current-conduction heated, using the slab (1) as a resistor, under a condition of being on or below an apparent current density (I) of from 40 (A/cm.sup.2) to 0.5 P.sup.2 +100 (A/cm.sup.2), P being a pressure of electrodes in kg/cm.sup.2.

Abstract: The present invention relates to a concentric multi-tube-system nozzle situated beneath the surface of the melt in a refining vessel, especially a refining vessel for converting molten pig iron into steel.The stability and life of the concentric double-tube nozzle is the most crucial factor in carrying out refining in a bottom-blown converter.In accordance with the present invention, there is provided a concentric multi-tube-system nozzle situated beneath the surface of the melt in a refining vessel, comprising:an inner tube;an outer tube positioned concentrically with respect to the inner tube and forming an annular clearance between the inner tube and the outer tube;spacers for circumferentially dividing the annular clearance; anda section defined by two adjacent spacers, the section comprising a contraction portion which is positioned essentially at the upstream side of the section. The contraction portion contributes to a uniform cooling of concentric double-tube nozzle in the circumference thereof.