Abstract: An environmentally friendly flux for molten steel desulfurization includes CaO and Al2O3 so that [CaO]/[Al2O3] is within a range of 1.6 to 3.0, and includes one or more alkali metal oxides of Na2O, K2O, and Li2O, and SiO2 so that [SiO2]/[R2O] is within a range of 0.1 to 3, [R2O] is within a range of 0.5 mass % to 5 mass %, and [SiO2] is within a range of 0.05 mass % to 15 mass % in a case in which the [CaO], the [Al2O3], the [SiO2], and the [R2O] represent the mass % of CaO, the mass % of Al2O3, the mass % of SiO2, and the total amount of the mass % of Na2O, the mass % of K2O, and the mass % of Li2O respectively.

Abstract: An environmentally friendly flux for molten steel desulfurization includes CaO and Al2O3 so that [CaO]/[Al2O3] is within a range of 1.6 to 3.0, and includes one or more alkali metal oxides of Na2O, K2O, and Li2O, and SiO2 so that [SiO2]/[R2O] is within a range of 0.1 to 3, [R2O] is within a range of 0.5 mass % to 5 mass %, and [SiO2] is within a range of 0.05 mass % to 15 mass % in a case in which the [CaO], the [Al2O3], the [SiO2], and the [R2O] represent the mass % of CaO, the mass % of Al2O3, the mass % of SiO2, and the total amount of the mass % of Na2O, the mass % of K2O, and the mass % of Li2O respectively.

Abstract: In order to quickly and economically evaluate cleanliness of a metal with high representativity when quantities, compositions, etc., of non-metallic inclusion particles existing in a metal and resulting in product defects are evaluated by a sample collected during the production process of the metal, the present invention provides an evaluation method involving the steps of levitation-melting a metal piece for a predetermined time by cold crucible levitation-melting means, discharging non-metallic inclusion particles contained in the metal piece to the surface of a molten metal, and directly analyzing a curved and non-smooth sample surface after solidification by a fluorescent X-ray analysis method using an energy dispersion type spectroscope, or by other chemical or physical measurements, to measure or analyze the quantities of elements constituting the non-metallic inclusion particles and to determine quantity of the non-metallic inclusions.

Abstract: In order to quickly and economically evaluate cleanliness of a metal with high representativity when quantities, compositions, etc., of non-metallic inclusion particles existing in a metal and resulting in product defects are evaluated by a sample collected during the production process of the metal, the present invention provides an evaluation method involving the steps of levitation-melting a metal piece for a predetermined time by cold crucible levitation-melting means, discharging non-metallic inclusion particles contained in the metal piece to the surface of a molten metal, and directly analyzing a curved and non-smooth sample surface after solidification by dissolving the surface and extracting and filtering the inclusions to measure or analyze the quantities of elements constituting the non-metallic inclusion particles and to determine quantity of the non-metallic inclusions.

Abstract: In order to quickly and economically evaluate cleanliness of a metal with high representativity when quantities, compositions, etc., of non-metallic inclusion particles existing in a metal and resulting in product defects are evaluated by a sample collected during the production process of the metal, the present invention provides an evaluation method involving the steps of levitation-melting a metal piece for a predetermined time by cold crucible levitation-melting means, discharging non-metallic inclusion particles contained in the metal piece to the surface of a molten metal, and directly analyzing a curved and non-smooth sample surface after solidification by a fluorescent X-ray analysis method using an energy dispersion type spectroscope, or by other chemical or physical measurements, to measure or analyze the quantities of elements constituting the non-metallic inclusion particles and to determine quantity of the non-metallic inclusions.

Abstract: A cast slab comprising fine particles of oxides and MnS, said oxide comprising an Mn silicate, with Mn oxide occupying 50 to 80% by weight of the sum of Mn oxide and Si oxide, unavoidably included oxides, and an optionally added oxide of at least one member selected from Zr, Ti, Ce, Hf, Y, and Al, said oxide having a size of 0.1 to 10 .mu.m being dispersed in an amount of 30 to 2000 pieces per mm.sup.2 of section of said cast slab. The dispersion of many oxide particles, which are likely to serve as nucli for the precipitation of MnS, in said cast slab can provide a plate steel having good toughness in a HAZ and a steel sheet product having excellent deep drawability.

Abstract: A method of oscillating a continuous caster mold at high frequencies comprises disposing a plurality of oscillators having substantially the same oscillating characteristic at appropriate intervals along or in the vicinity of a line where liquid metal contacts an inner lining of a mold, connecting the tip of each oscillator to the inner lining so that the axis of the oscillator extends at right angles to the surface of the inner lining, and supplying power from an oscillation generator to each oscillator so that the oscillation frequencies of any two adjoining oscillators are differentiated within the limit of 2 KHz. Thus, any two adjoining oscillators oscillate the inner lining at right angles to the surface thereof at mutually differentiated frequencies.