Abstract: Disclosed is a refractory product for casting of steel, which is capable of forming a dense surface layer which is high in terms of a slag infiltration suppressing ability and strong, in a surface region thereof efficiently or sufficiently or in an optimum state. The refractory product contains 1 mass % or more of free carbon, and 2 mass % to 15 mass % of an aluminum component as metal, with the remainder comprising a refractory material as a main composition, wherein the refractory product has a permeability of 1×10?16m2 to 15×10?16m2.

Abstract: A simplified and downsized coupling position switching mechanism capable of transmitting reliably and smoothly the driving force of the drive unit to the slide metal frame to switchably change a coupling position between the slide metal frame and the drive unit in the sliding nozzle apparatus. A coupling portion in the slide metal frame protrudes on the side of the drive unit and allows a rod head of the drive unit to be coupled thereto, and the coupling portion has a coupling space allows the rod head to be disposed movably in a sliding direction of the slide metal frame. A separator is inserted into the coupling space to divide the coupling space into first and second coupling chambers in the sliding direction of the slide metal frame. The coupling portion has a fitting section for allowing the separator to be fitted thereinto when it is inserted into the coupling space.

Abstract: In a sliding nozzle comprising three plates consisting of an upper plate, an intermediate plate capable of a sliding movement, and a lower plate, it is intended to suppress adhesion and deposition of metal oxides and others on wall surfaces of inner bores of the three plates. The intermediate plate has: a first inclined portion whose surface defines a slidingly closing directional leading-side wall surface of an inner bore thereof and extends obliquely downwardly in a diametrically contracting direction; a second inclined portion whose surface defines an upper part of a slidingly closing directional trailing-side wall surface of the inner bore thereof and extends obliquely downwardly in a diametrically contracting direction, and a third inclined portion whose surface defines a lower part of the slidingly closing directional trailing-side wall surface of the inner bore thereof and extends obliquely downwardly in a diametrically expanding direction.

Abstract: A coupling position switching mechanism capable of improving efficiency of a coupling position switching operation, while realizing structural simplification, and reductions in size and cost. A first coupling portion consisting of one of a slide metal frame-side coupling portion and a drive unit-side coupling portion is formed with a groove-shaped recess and a through-hole in this order from the side of a distal end of the first coupling portion, and a second coupling portion consisting of the remaining one of the slide metal frame-side coupling portion and the drive unit-side coupling portion is formed with the through-hole.

Abstract: Provided are a magnesia carbon brick which does not include graphite yet has excellent spalling and corrosion resistances, and a method for producing thereof. The brick is obtained by adding an organic binder to a refractory raw material mixture followed by kneading, molding, and heat-treating, wherein the mixture includes total 0.1 to 2.0 mass % of pitch and/or carbon black, total 0.1 to 1.0 mass % of aluminum and/or aluminum alloy, 3.0 to 10.0 mass % of magnesia having particle diameter of less than 0.075 mm, and 87.0 to 96.0 mass % of magnesia having particle diameter of 0.075 to 5 mm; and a mass ratio of magnesia having particle diameter of 1 to 5 mm to that of 0.075 to 1 mm is 1.66 to 2.34; graphite is not included therein; and an apparent porosity thereof after heat-treatment under reductive atmosphere at 1400° C. for 3 hours is 8.0% or less.

Abstract: In the method for replacing an immersion nozzle while pushing out a used immersion nozzle by a new immersion nozzle, in order to minimize leakage of molten steel during the replacement, to enable the use of a shaped joint sealer in a joint interface, and to ensure high sealability, a concave portion is formed on the new immersion nozzle's upper plane so as to include a nozzle hole, and the shaped joint sealer is mounted in this concave portion. The immersion nozzle's upper plane is caused to slide while being pressed to the upper nozzle's lower plane.

Abstract: An immersion nozzle for use with an immersion nozzle replacement apparatus, capable of preventing crack formation due to the presence of a neck region. The immersion nozzle includes a nozzle body, a flange, and a metal casing. The nozzle body is formed such that a region of an outer peripheral surface thereof located above a point of power of an upward supporting force from a supporting device extends vertically up to an upper edge of the nozzle body without any dimensional change with respect to an central axis of an inner bore of the nozzle body. The outer peripheral surface region is not joined to the metal casing.

Abstract: A precast refractory block for a coke oven having high hot strength and stable under-load expansion/shrinkage behavior at high temperatures. Specifically, a silica-based precast refractory block contains a P2O5 component in an amount of 0.3 to 2.0 mass %.

Abstract: A nozzle structure for discharging molten steel with improved sealing performance. The nozzle structure comprises: a molten steel discharge path having an inner bore; and one or more joints through which the molten steel discharge path is divided at one or more positions in a orthogonal direction with respect to an upward-downward direction of discharge of molten steel, and which join the molten steel discharge path. An inner bore sleeve is formed of a refractory material, and provided on an inner bore surface of the nozzle structure to extend in the upward-downward direction across at least one of the joints.

Abstract: A coupling position switching mechanism capable of improving efficiency of a coupling position switching operation, while realizing structural simplification, and reductions in size and cost. A first coupling portion consisting of one of a slide metal frame-side coupling portion and a drive unit-side coupling portion is formed with a groove-shaped recess and a through-hole in this order from the side of a distal end of the first coupling portion, and a second coupling portion consisting of the remaining one of the slide metal frame-side coupling portion and the drive unit-side coupling portion is formed with the through-hole.

Abstract: A cordierite-based sintered body comprises cordierite as a primary crystal phase and LaMgAl11O19 as a secondary crystal phase, wherein a ratio ILMA (114)/IMAS (004) is in the range of 0.01 to 0.8, where the ILMA (114) denotes a peak intensity of a (114) plane of LaMgAl11O19 as measured by powder X-ray diffractometry, and the IMAS (004) denotes a peak intensity of a (004) plane of cordierite as measured by powder X-ray diffractometry. The disclosure is intended to enhance mechanical property and improve complex and fine processability for a cordierite-based sintered body without compromising low thermal expansibility, high dimensional long-term stability, high stiffness (high elastic modulus) and precision polishing characteristic.

Abstract: In order to address the technical problem of allowing an unshaped refractory material using a spinel-containing alumina cement to provide further improved corrosion resistance and slag infiltration resistance while reducing the occurrence of crack/peeling, an unshaped refractory material is provided which comprises a refractory raw material mixture having a particle size of 8 mm or less, with the refractory raw material mixture having an alumina cement at least a part of which is a spinel-containing alumina cement, and, with respect to 100 mass % of the refractory raw material mixture, the alumina cement contains CaO in an amount of 0.5 to 2.5 mass %, and the spinel-containing alumina cement contains spinel in an amount of 3.5 to 10.5 mass %.

Abstract: The present invention is intended to enhance mechanical property and improve complex and fine processability for a cordierite-based sintered body without compromising low thermal expansibility, high dimensional long-term stability, high stiffness (high elastic modulus) and precision polishing characteristic. The cordierite-based sintered body of the present invention comprises cordierite as a primary crystal phase and LaMgAl11O19 as a secondary crystal phase, wherein a ratio ILMA (114)/IMAS (004) is in the range of 0.01 to 0.8, where the ILMA (114) denotes a peak intensity of a (114) plane of LaMgAl11O19 as measured by powder X-ray diffractometry, and the IMAS (004) denotes a peak intensity of a (004) plane of cordierite as measured by powder X-ray diffractometry.

Abstract: A simplified and downsized coupling position switching mechanism capable of transmitting reliably and smoothly the driving force of the drive unit to the slide metal frame to switchably change a coupling position between the slide metal frame and the drive unit in the sliding nozzle apparatus. A coupling portion in the slide metal frame protrudes on the side of the drive unit and allows a rod head of the drive unit to be coupled thereto, and the coupling portion has a coupling space allows the rod head to be disposed movably in a sliding direction of the slide metal frame. A separator is inserted into the coupling space to divide the coupling space into first and second coupling chambers in the sliding direction of the slide metal frame. The coupling portion has a fitting section for allowing the separator to be fitted thereinto when it is inserted into the coupling space.

Abstract: A refractory material contains: 40 mass % or more of MgO; 4 to 30 mass % of a free carbon component; and one or more of B2O3, P2O5, SiO2 and TiO2, in a total amount of 0.3 to 3 mass %, with the remainder being at least one other type of additional refractory component. A void layer exists in an interface between a carbon-containing matrix microstructure residing at least on opposite sides of a maximum-size one of a plurality of MgO-containing particles in the refractory material, and the maximum-size MgO-containing particle. A sum of respective thicknesses of the void layer at two positions on the opposite sides is 0.2 to 3.0% of a ratio with respect to particle size of the maximum-size MgO-containing particle. An inorganic compound of MgO and the one or more of B2O3, P2O5, SiO2 and TiO2 exists entirety or partially in a surface of each of the MgO-containing particles.

Abstract: A refractory to be used repeatedly or for a long period of time, such as a refractory for casting, especially a nozzle for casting and an SN plate, has improved tolerance. The refractory for casting contains Al4O4C in the range of 15 to 60% by mass, both inclusive, an Al component as a metal in the range of 1.2 to 10.0% by mass, both inclusive, and a balance including Al2O3, a free C, and other refractory component; a sum of Al4O4C, Al2O3, and the Al component as a metal is 85% or more by mass; and a content of Al4O4C (Al4O4C), a content of the Al component as a metal (Al), and a content of the free carbon (C). The contact of the free carbon satisfies the following Equation 1 and Equation 2: 1.0?C/(Al4O4C×0.038+Al×0.33) (Equation 1) and 1.0?C/(Al4O4C×0.13+Al×0.67) (Equation 2).

Abstract: A sliding nozzle device that can reduce any damage such as surface roughness and chipping in a nozzle hole surroundings of a used plate.

Abstract: With a view to adding, to an upper nozzle formed with a bore having a shape capable of creating a less energy loss or smooth (constant) molten steel flow to suppress the occurrence of adhesion of inclusions and metals in molten steel, a gas injection function to thereby further suppress the occurrence of the adhesion, the present invention provides a method of using an upper nozzle configured to have a cross-sectional shape of a wall surface defining the bore, taken along an axis of the bore, comprising a curve represented by the following formula: log(r (z))=(1/n)×log((H+L)/(H+z))+log(r (L)) (n=1.5 to 6), where: L is a length of the upper nozzle; H is a calculational hydrostatic head height; and r (z) is an inner radius of the bore at a position downwardly away from an upper edge of the bore by a distance z. The method comprises using the upper nozzle in such a manner as to satisfy the following relationship: RG?4.

Abstract: Disclosed is a technique for suppressing a firing property and a dust generating property while improving bondability, in a thermal spray material for use in a thermite spraying process. The thermal spray material comprises a refractory material powder and a metal Si powder and capable of being sprayed onto a target surface using oxygen or oxygen-containing gas as a carrier gas and melt-adhered to the target surface based on heat generated by combustion of the metal Si powder, wherein the metal Si powder is contained in an amount of 10 to 25 mass % with respect to the entire thermal spray material, and wherein the metal Si powder has a median size of 10 ?m or less, and contains a fraction having a particle size of 2 ?m or less in an amount of 8 mass % or less with respect to the entire metal Si powder.