Krosakiharima Corporation

Joki Yoshitomi

Katsumi Morikawa

Keiichiro Akamine

Keisuke Asano

Toshiyuki Hokii

Masato Tanaka

Yoshihiko Uchida

Tsuneo Kayama

Koichi Haren

Eiichiro Hatae

Saeko Uchida

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

In a carbon-containing refractory composed of a refractory aggregate, a carbon based raw material, and a carbon bond connecting between the refractory aggregate or the carbon based raw material, transition metal-containing nanoparticles having particle diameters of 1,000 nm or less and containing a transition metal are contained in the above-described carbon bond while being dispersed. When the carbon-containing refractory is heat-treated, flexible structures of carbon fiber-shaped textures having diameters of 50 nm or less are formed in the inside of a carbon bond and, thereby, an increase in strength, a reduction in modulus of elasticity, and a reduction in thermal expansion coefficient are facilitated. Therefore, a carbon-containing refractory exhibiting high thermal shock resistance, high abrasion resistance, and high corrosion resistance are provided.

Refractory, method for manufacturing refractory, and refractory raw material

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, BC, MgB, CaB, and CrB may be further added in an amount of 0.1 to 3 mass %, in addition to 100 mass % of the refractory raw material mix, to enhance strength and oxidation resistance and further enhance the durability. The magnesia raw material may comprise a first particle fraction having a particle diameter of greater than 10 to 500 &#x3bc;m and occupying 20 to 50 mass % in the refractory raw material mix, and a second particle fraction having a particle diameter of 10 &#x3bc;m or less and occupying 5 mass % or less in the refractory raw material mix, to additionally enhance corrosion resistance and thermal shock resistance.

High-durability sleeve bricks

A nozzle for continuous casting of clean steel is capable of preventing adhesion of AlO-based inclusions to a wall surface of the inner hole of the nozzle while fully achieving an effect of a swirl vane. The swirl vane prevents drift in molten steel passing through the inner hole. The swirl vane is disposed in the inner hole. A wall surface is at least partly formed as a tubular-shaped refractory layer and is prepared by controlling a weight ratio of CaO/MgO and an apparent porosity to have a thickness of 3 to 20 mm, so as to prevent adhesion of AlO-based inclusions to the wall surface and the swirl vane while effectively maintaining the anti-drift effect for long hours. Further, inert gas is injected into a molten steel flow between an upper nozzle and the swirl vane to facilitate surfacing of AlO-based inclusions in a mold and reduce AlO-based inclusions in molten steel so as to achieve stable casting operation and high-quality steel with high cleanness.

Growing community of inventors

Fukuoka, Japan

Joki Yoshitomi