Abstract: Provided is a molten metal discharge nozzle capable of suppressing turbulence in a molten metal stream passing through an inner bore thereof, with a simple structure. A cross-sectional shape of a wall surface of the inner bore, taken along an axis of the inner bore, comprises a part or an entirety of a curved line expressed by the following formula: log(r(z))=(1/n)×log((Hc+L)/(Hc+z))+log(r(L)) (1), where: 6?n?1.

Abstract: Provided is an aluminum oxycarbide composition production method capable of increasing a yield of Al4O4C while reducing a content rate of Al4C3 and achieving high productivity, and an aluminum oxycarbide composition. The method comprises: preparing a blend substantially consisting of a carbon-raw material having a mean particle diameter of 0.5 mm or less and an alumina-raw material having a mean particle diameter of 350 ?m or less, wherein a mole ratio of the carbon-raw material to the alumina-raw material (C/Al2O3) is in a range of 0.8 to 2.0; homogeneously mixing the blend to allow a variation in C component to fall within ±10%; and melting the obtained mixture in an arc furnace at 1850° C. or more.

Abstract: It is intended to uniform and straighten a molten steel stream flowing out of a discharge port of an immersion nozzle, and thus suppress mold powder entrapment in the vicinity of the immersion nozzle. The immersion nozzle comprises a tubular-shaped straight nozzle body formed to extend in a vertical longitudinal direction and adapted to allow molten steel from a molten-steel inlet provided at an upper end thereof to pass downwardly therethrough, and a pair of discharge ports provided in a lower portion of the straight nozzle body in bilaterally symmetrical relation and adapted to discharge the molten steel from a lateral surface of the straight nozzle body in a lateral direction.

Abstract: It is an object to provide an aluminum oxycarbide composition capable of suppressing oxidation of Al4O4C during use to maintain advantageous effects of Al4O4C for a long time. In an aluminum oxycarbide composition comprising Al4O4C crystals, the Al4O4C crystals have an average diameter of 20 ?m or more, based on an assumption that a cross-sectional area of each Al4O4C crystal during observation of the aluminum oxycarbide composition in an arbitrary cross-section thereof is converted into a diameter of a circle having the same area as the cross-sectional area. This aluminum oxycarbide composition can be produced by subjecting a carbon-based raw material and an alumina-based raw material to melting in an arc furnace and then cooling within the arc furnace.

Abstract: Disclosed is anti-alumina-buildup refractories for casting nozzles, which comprises a refractory aggregate including 20 mass % or more of CaO component, and 10 mass % or more of clinker particles each containing CaO as a mineral phase, on the basis of 100 mass % of the entire composition. At least a part of the surfaces of the CaO exposed from the surfaces of the corresponding clinker particles is formed with a CaCO3 film. The CaCO3 film releases CO2 gas through thermal decomposition to smooth an operative surface of the nozzle so as to prevent the accretion of metal thereon, so that CaO is continuously supplied to alumina attached on the operative surface to prevent alumina buildup. In addition, the CaCO3 film effectively prevents the hydration of CaO due to a hydration reaction.

Abstract: The present invention provides a plate brick having a low amount of generation of smoke and a gas with a pungent odor during use, and exhibiting high durability. A plate brick of the present invention is obtained by: adding an organic binder to a refractory raw material mixture containing 0.5 to 20 mass % of aluminum and/or aluminum alloy; kneading the mixture with the organic binder; forming the kneaded mixture into a shaped body; and subjecting the shaped body to a heat treatment at a temperature of 400 to 1000° C., wherein the plate brick is obtained without being impregnated with a carbon-containing liquid material comprising tar or pitch, after the heat treatment. The plate brick has a compressive strength of 180 MPa or more, and a weight-increasing rate of 1% or less as measured in a hydration test using an autoclave.

Abstract: Provided is a molten metal discharge nozzle which has a bore configuration capable of creating a low-energy loss and smooth (stabilized) molten metal flow to suppress the occurrence of an adhesion matter. In the molten metal discharge nozzle, a radius r(0) of an upper end (12) of a bore (11) thereof is 1.5 times or more a radius r(L) of a lower end (13) of the bore, and a cross-sectional shape of a bore wall surface 14 taken along an axis of the bore has no bend point. Further, a radius r(z) of the bore at a position downwardly away from the upper end of the bore by a distance z (where L is an axial length of the bore) is in a range between [[L/{(r(0)/r(L))1.5?1}+L]/[L{r(0)/r(L))1.5?1}+z]]1/1.5×r(L) and [[L/{(r(0)/r(L))6?1}+L]/[L/{(r(0)/r(L))6?1}+z]]1/6×r(L).

Abstract: In an operation of continuous casting of steel grade such as aluminum-killed steel where a nozzle clogging phenomenon is particularly likely to occur, it is intended to prevent adhesion of inclusions (typically, Al2O3) on a nozzle used in the casting operation, and clogging of the nozzle due to the inclusions. A refractory material 10 is arranged to define a part or an entirety of a molten steel-contacting surface of a continuous casting nozzle, wherein the refractory material 10 contains: a CaO component in an amount of 0.5 mass % or more; one or both of B2O3 and R2O (R is one selected from the group consisting of Na, K and Li) in an amount of 0.5 mass % or more; Al2O3 in an amount of 50 mass % or more; and free carbon in an amount of 8.0 to 34.5 mass %, and wherein a total amount of CaO, B2O3 and R2O is in the range of 1.0 to 15.0 mass %, and a mass ratio of CaO/(B2O3+R2O) is in the range of 0.1 to 3.0.

Abstract: The present invention is directed to creating a less-energy loss or smooth (constant) molten steel flow with a focus on a configuration of a bore of an upper nozzle, so as to provide an upper nozzle formed with a bore having a configuration capable of to suppress deposit formation. For this purpose, in an upper nozzle 10 for allowing molten steel to flow therethrough, a radius of an upper end of a bore 11 is set to be equal to or greater than 1.5 times a radius of a lower end of the bore 11, and a bore surface 14 is formed in a vertical cross-sectional configuration represented by log(r(z))=(1/n)×log((H+L)/(H+z))+log(r(L))(n=1.5 to 6).

Abstract: The present invention is intended to drastically improve a precision polishing characteristic of a cordierite-based sintered body which has low thermal expansibility, high dimensional long-term stability and high rigidity (high elastic modulus). The cordierite-based sintered body comprises cordierite as primary components, and one or more selected from the group consisting of La, Ce, Sm, Gd, Dy, Er, Yb and Y in an oxide-equivalent amount of 1 to 8 mass %, without any crystal phase other than a cordierite crystal phase. A mass ratio of primary components of the cordierite satisfies the following relations: 3.85?SiO2/MgO?4.60, and 2.50?Al2O3/MgO?2.70, and the cordierite-based sintered body after being subjected to precision polishing has a precisely polished surface with an average surface roughness (Ra) of 1 nm or less.

Abstract: The present invention provides an SN plate capable of being formed in a large size while using a highly corrosion resistant and highly thermally expansible refractory product. In the SN plate of the present invention, a specific refractory member 1a having a thermal expansion rate as measured at 1500° C. of 1.15 to 2.50% due to addition of aluminum for improving corrosion resistance is arranged as a part of the SN plate to cover at least a practically critical region of the SN plate. A thickness of the specific refractory member is set in a range of 15 to 25 mm. A portion of the SN plate other than the specific refractory member is made up of an unburned or burned refractory product consisting primarily of an alumina-carbon composite.

Abstract: In a insert-type continuous casting nozzle comprising a highly functional layer formed to have a high corrosion resistance, a high anti-attachment capability, etc., and provided to define an inner bore thereof, the present invention is directed to providing a refractory material (mortar) for an intermediate layer of the continuous casting nozzle, which has a property capable of fixing an inner bore-side layer to an outer periphery-side layer (a nozzle body) of the continuous casting nozzle, while preventing the occurrence of expansion splitting in the outer periphery-side layer due to a difference in thermal expansion between the inner bore-side and outer periphery-side layers, and a continuous casting nozzle using the refractory material for the intermediate layer.

Abstract: The present invention is intended to drastically improve a precision polishing characteristic of a cordierite-based sintered body which has low thermal expansibility, high dimensional long-term stability and high rigidity (high elastic modulus). The cordierite-based sintered body comprises cordierite as primary components, and one or more selected from the group consisting of La, Ce, Sm, Gd, Dy, Er, Yb and Y in an oxide-equivalent amount of 1 to 8 mass %, without any crystal phase other than a cordierite crystal phase. A mass ratio of primary components of the cordierite satisfies the following relations: 3.85?SiO2/MgO?4.60, and 2.50?Al2O3/MgO?2.70, and the cordierite-based sintered body after being subjected to precision polishing has a precisely polished surface with an average surface roughness (Ra) of 1 nm or less.

Abstract: It is intended to provide a taphole mix capable of forming SiC bonds with minimum of an excess and a deficiency in components thereof, and excellent in drillability. A fine particle fraction having a particle diameter of 75 ?m or less is comprised of three components consisting of a silicon nitride-based material, a carbon-based material, and roseki, or comprised of the three component, and one or more selected from the group consisting of an alumina-based material, a silicon carbide-based material, a rare-earth element oxide-based material, clay, a high-purity silica-based material containing SiO2 in an amount of 80 mass % or more, a boron compound-based material in an amount of less than 0.3 mass % with respect to 100 mass % of the silicon nitride-based material, and a metal powder in an amount of less than 10 mass % with respect to 100 mass % of the carbon-based material.

Abstract: A continuous-casting-nozzle support apparatus capable of enhancing sealing performance between a continuous casting nozzle and an SN device. The continuous-casting-nozzle support apparatus comprises: a holding mechanism 40 disposed to extend from a stationary column 10 fixed onto a supporting surface, and adapted to be turnable in a horizontal direction and swingable or movable in an upward-downward direction; a lifting mechanism 70 provided on the side of a distal end of the holding mechanism 40; a supporting mechanism 80 provided on the side of a distal end of the lifting mechanism 70, and adapted to support a continuous casting nozzle 100; and a hooking device 90 provided in the lifting mechanism 70, and adapted to allow the lifting mechanism 70 to be hooked to a first engagement portion 111a formed on a sliding metal frame of a sliding nozzle device 110, wherein the lifting mechanism 70 is adapted to lift the continuous casting nozzle 100 through the supporting mechanism 80.

Abstract: It is intended to develop a technique of pressing and fixing a plate by a uniform force to suppress the occurrence of a crack around a nozzle hole of the plate during use, and provide a sliding nozzle device capable of improving durability of the plate, and a plate for use in the sliding nozzle device. The sliding nozzle device comprises a plate (2) and a plate-receiving metal frame (1) for fixedly holding the plate (2).

Abstract: Provided is a zirconia-mullite refractory raw material which is less likely to undergo alternation and microstructural degradation under high-temperature conditions, and low in thermal expansion rate, so as to have thermal shock resistance and corrosion resistance. The zirconia-mullite refractory raw material comprises crystalline zirconia and mullite as primary components, with the remainder being corundum and/or a matrix glass, wherein the crystalline zirconia includes a eutectic zirconia crystal having a grain size of 1.0 ?m or less, and has a maximum grain size of 30 ?m or less, and the matrix glass is contained in an amount of 5 mass % or less. The zirconia-mullite refractory raw material has a chemical composition comprising 30 to 55 mass % of ZrO2, 30 to 55 mass % of Al2O3 and 10 to 25 mass % of SiO2, wherein each of the chemical components falls within a primary phase region of ZrO2 in an Al2O3—ZrO2—SiO2 system phase diagram.

Abstract: Provided is an aluminum oxycarbide composition production method capable of increasing a yield of Al4O4C while reducing a content rate of Al4C3 and achieving high productivity, and an aluminum oxycarbide composition. The method comprises: preparing a blend substantially consisting of a carbon-raw material having a mean particle diameter of 0.5 mm or less and an alumina-raw material having a mean particle diameter of 350 ?m or less, wherein a mole ratio of the carbon-raw material to the alumina-raw material (C/Al2O3) is in a range of 0.8 to 2.0; homogeneously mixing the blend to allow a variation in C component to fall within ±10%; and melting the obtained mixture in an arc furnace at 1850° C. or more.

Abstract: Disclosed is a reactive working material for use in a process of producing hydrogen by splitting water based on a two-step thermochemical water-splitting cycle through the utilization of solar heat, industrial waste heat or the like, which comprises a ferrite fine powder and a cubic zirconia supporting the ferrite fine powder. This reactive working material makes it possible to prevent scaling off of the ferrite fine powder from the zirconia fine powder due to volumetric changes of the ferrite fine powder during repeated use, and suppress growth of FeO grains due to repetition of melting and solidification when used as a reactive working material for a cyclic reaction under a high temperature of 1400° C. or more.

Abstract: Disclosed is a magnesia-carbon based sleeve brick for steelmaking converters, which is obtained by adding, to a refractory raw material mix containing 60 to 95 mass % of a magnesia raw material and 5 to 20 mass % of graphite, a metal powder of one or more selected from the group consisting of Al, Si, Mg, Ca, Cr and an alloy thereof, in an amount of greater than 3 to 6 mass %, and an organic binder, in addition to 100 mass % of the refractory raw material mix, and subjecting the resulting mixture to kneading, forming and heat treatment, wherein the sleeve brick is used under a condition that a thickness thereof is set at 70 mm or less. This makes it possible to prevent cracking which would otherwise occur in the sleeve brick itself, to allow the sleeve brick to have enhanced durability. One or more selected from the group consisting of B, B4C, MgB2, CaB6, and CrB may be further added in an amount of 0.