Krosakiharima Corporation

Keiichiro Akamine

Joki Yoshitomi

Katsumi Morikawa

Kazuo Ito

Yoshihiko Uchida

Taro Makino

Masako Takenami

Zenta Oomaru

Tsuneo Kayama

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 AlOC 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 AlO, a free C, and other refractory component; a sum of AlOC, AlO, and the Al component as a metal is 85% or more by mass; and a content of AlOC (AlOC), 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&#x2266;C/(AlOC&#xd7;0.038+Al&#xd7;0.33)&#x2003;&#x2003;(Equation 1)and1.0&#x2267;C/(AlOC&#xd7;0.13+Al&#xd7;0.67)&#x2003;&#x2003;(Equation 2).

Refractory for casting, nozzle for casting and sliding nozzle plate using same

It is an object to provide an aluminum oxycarbide composition capable of suppressing oxidation of AlOC during use to maintain advantageous effects of AlOC for a long time. In an aluminum oxycarbide composition comprising AlOC crystals, the AlOC crystals have an average diameter of 20 &#x3bc;m or more, based on an assumption that a cross-sectional area of each AlOC 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.

Aluminum oxycarbide composition, production method therefor, and refractory material

Disclosed is a method of producing a plate brick, which comprises: adding an organic binder to a refractory raw material mixture containing aluminum and/or an aluminum alloy; kneading them; forming the kneaded mixture into a shaped body; and burning the shaped body in a nitrogen gas atmosphere at a temperature of 1000 to 1400&#xb0; C., wherein: when a temperature of a furnace atmosphere is 300&#xb0; C. or more, the atmosphere is set to a nitrogen gas atmosphere; and when the temperature of the furnace atmosphere is 1000&#xb0; C. or more, an oxygen gas concentration in the atmosphere is maintained at 100 volume ppm or less, and a sum of a carbon monoxide gas concentration and a carbon dioxide gas concentration is maintained at 1.0 volume % or less. This makes it possible to form a large amount of fine and uniform aluminum nitride in a plate brick to prevent microstructural degradation due to hydration caused by formation of aluminum carbide and suppress oxidation of a carbon bond so as to improve surface-roughening resistance.

Plate brick production method and plate brick

Provided is an aluminum oxycarbide composition production method capable of increasing a yield of AlOC while reducing a content rate of AlCand 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 &#x3bc;m or less, wherein a mole ratio of the carbon-raw material to the alumina-raw material (C/AlO) is in a range of 0.8 to 2.0; homogeneously mixing the blend to allow a variation in C component to fall within &#xb1;10%; and melting the obtained mixture in an arc furnace at 1850&#xb0; C. or more.

Aluminum oxycarbide composition and production method therefor

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 &#x3bc;m or less, and has a maximum grain size of 30 &#x3bc;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 ZrO, 30 to 55 mass % of AlOand 10 to 25 mass % of SiO, wherein each of the chemical components falls within a primary phase region of ZrOin an AlO&#x2014;ZrO&#x2014;SiOsystem phase diagram.

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Fukuoka, Japan

Keiichiro Akamine