Abstract: A hot-rolled steel sheet for a generator rim contains a structure containing a ferrite phase with an areal ratio of 95% or more in which precipitates containing Ti and V whose average grain diameter is less than 10 nm are precipitated in crystal grains of the ferrite phase. The ferrite phase has an average crystal grain diameter within the range of 2 ?m or more and less than 10 ?m. The hot-rolled steel sheet for a generator rim has strength with a yield strength YS in a rolling direction of 700 MPa or more and electromagnetic properties with a magnetic flux density B50 of 1.5 T or more and a magnetic flux density B100 of 1.6 T or more.

Abstract: A hot-rolled steel sheet for a generator rim contains a structure containing a ferrite phase with an areal ratio of 95% or more in which precipitates containing Ti and V whose average grain diameter is less than 10 nm are precipitated in crystal grains of the ferrite phase. The ferrite phase has an average crystal grain diameter within the range of 2 ?m or more and less than 10 ?m. The hot-rolled steel sheet for a generator rim has strength with a yield strength YS in a rolling direction of 700 MPa or more and electromagnetic properties with a magnetic flux density B50 of 1.5 T or more and a magnetic flux density B100 of 1.6 T or more.

Abstract: A method for continuous casting of a slab comprises feeding molten steel into a mold through exit ports of an immersion nozzle and controlling a stream of the molten steel by means of an electromagnetic stirrer having a linearly shifting magnetic field. The direction of the linearly shifting magnetic field is toward the immersion nozzle, which is positioned at the center of the mold from a pair of narrow sides of the mold. A first frequency control step controls a frequency of a wave of the shifting magnetic field to be higher than a threshold frequency, wherein the wave has a period equal to the time during which the stream of the molten steel poured from the immersion nozzle passes through an area to which the linearly shifting magnetic field is introduced, said area having an upper limit and a lower limit.

Abstract: An immersion nozzle for continuous casting of molten steel comprises: an immersion nozzle body having a bore for introducing molten steel supplied from a tundish into a continuous casting mold; two exit ports located symmetrically about the vertical center axis of the immersion nozzle body at a lower portion of the immersion nozzle body for introducing the molten steel into the continuous casting mold; gas blow-in inlets in an inwall of the immersion nozzle body, the center axis line of the blow-in inlets crossing, at right angle, a vertical plane passing through a line connecting the respective centers of the exit ports; and gas blow conduits, each being connected respectively to one of the gas blow-in inlets. The gas blow-in inlets have a height almost equal to a vertical length across the exit ports, the top of the gas blow-in inlets being from 0 to 100 mm above the upper end of the exit ports.

Abstract: An immersion nozzle for continuous casting of steel comprises an immersion nozzle body for introducing molten steel supplied form a tundish into a continuous casting mold, the immersion nozzle body having two exit ports located symmetrically about a vertical center axis of the immersion nozzle body at a lower portion thereof and being immersed in the molten steel in the mold. The immersion nozzle body has a bore which includes first and second sectional areas, the first sectional area being at and below the two exit ports and being smaller than the second sectional area, the second sectional area being above the two exit ports, and the molten steel passing through the bore and out through the two exit ports. The bore has an inner diameter at the level of the two exit ports which is substantially equal to a horizontal inner length or diameter of the two exit ports. A ratio represented by (A)/(B) is from 0.5 to 0.