Krosakiharima Corporation

Hitachi Metals, Ltd.

Kurosaki Refractories Co., Ltd.

Krosaki Corporation

Nippon Steel Sumitomo Metal Corporation

Katsumi Morikawa

Joki Yoshitomi

Akinari Sasaki

Norio Takahashi

Mitsuru Yano

Keiichiro Akamine

Keisuke Asano

Masatoshi Nakamizo

Tomoyuki Kido

Ling Li

Masatoshi Kawata

Shinichi Fukunaga

Yoshitaka Hiraiwa

Hiroshi Otsuka

Toshiyuki Hokii

Kazuhisa Tanaka

Yoshihiko Uchida

Taro Makino

Takashi Sadano

Yuichi Tsukaguchi

Jyouki Yoshitomi

Shigefumi Matsumoto

Kouhei Takami

Saeko Uchida

Daisuke Yoshitsugu

Keiichiro Neba

Koichi Haren

Tsuneo Kayama

Naomi Yoshitsugu

Li Ling

Provided is a refractory product which is not impregnated with pitch or the like, wherein it has higher corrosion-erosion resistance and thermal shock resistance as compared to a refractory product subjected to pitch or the like-impregnation treatment. The refractory product which is not impregnated with tar or pitch is characterized in that, in terms of values of physical properties of a sample of the refractory product as measured after heat-treating the sample in a non-oxidizing atmosphere at 1200° C.: an apparent porosity is 7% or less; a total void volume of pores having a pore diameter of 1 μm or less is 80% or more of an integrated void volume of pores of the entire sample of the refractory product; and a gas permeability is 50×10mor less.

Refractory product

A refractory material contains: 40 mass % or more of MgO; 4 to 30 mass % of a free carbon component; and one or more of BO, PO, SiOand TiO, 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 BO, PO, SiOand TiOexists entirety or partially in a surface of each of the MgO-containing particles.

Refractory material and casting nozzle

A refractory product includes CaO component-containing refractory particles and MgO component-containing refractory particles. The refractory material contains, a chemical composition measured after it has undergone heating in a non-oxidizing atmosphere at 1000&#xb0; C., one or more of the following metal oxides BO, TiO, VO, POand SiOin a total amount of 0.1 to 5.0 mass %, and free carbon in an amount of 2 to 35 mass %, with the remainder including CaO and MgO whose mass ratio (CaO/MgO) is in the range of 0.1 to 1.5. In microscopic observation performed at room temperature on the refractory material which has undergone the above heating, an inorganic film comprised of CaO and the one or more metal oxides is formed in at least each CaO surface of the refractory particles each containing either one or both of a CaO component and an MgO component, with a thickness of 0.1 to 25 &#x3bc;m.

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

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, AlO) on a nozzle used in the casting operation, and clogging of the nozzle due to the inclusions. A refractory materialis arranged to define a part or an entirety of a molten steel-contacting surface of a continuous casting nozzle, wherein the refractory materialcontains: a CaO component in an amount of 0.5 mass % or more; one or both of BOand RO (R is one selected from the group consisting of Na, K and Li) in an amount of 0.5 mass % or more; AlOin 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, BOand RO is in the range of 1.0 to 15.0 mass %, and a mass ratio of CaO/(BO+RO) is in the range of 0.1 to 3.0.

Refractory material, continuous casting nozzle using the refractory material, production methods for the continuous casting nozzle, and continuous casting methods using the continuous casting nozzle

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. The refractory material for the intermediate layer contains a hollow refractory aggregate in an amount of 10 to 75 volume %, wherein a ratio of an average radius R of each particle of the aggregate to an average wall thickness t of the particle satisfies the following relation: R/t&#x2267;10. This refractory material is disposed between an inner bore-side layer () and an outer periphery-side layer () of a continuous casting nozzle.

Refractory material for nozzle for use in continuous casting, and continuous casting nozzle

A zirconia-carbon-containing refractory includes aggregate grains, a carbon bond formed between the aggregate grains, 80% by mass or more of a ZrOcomponent, and a carbonaceous material, in which the total volume of open pores and the carbonaceous material in the structure of the refractory is in the range of 25% to 42% by volume, open pores each having a diameter of 10 &#x3bc;m or more account for 30% or less of the total volume of open pores in the structure of the refractory, and carbonaceous material grains each having a maximum length exceeding 45 &#x3bc;m in the carbonaceous material in the zirconia-carbon-containing refractory account for less than 60% by mass of the total mass of the carbonaceous material except the bonding carbon in the zirconia-carbon-containing refractory.

Zirconia-carbon-containing refractory and method for producing same

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.

Immersion nozzle for continuous casting of steel and continuous steel casting method using same

A casting apparatus for low-melting metals has a coating layer of two-layered structure which hardly reacts with low-melting metals, adheres firmly to the substrate, and protects the substrate from thermal and mechanical shocks for a long period of time. The layer in contact with the substrate contains glass powder having a melting point below 1000.degree. C. and at least one binder selected from silicates and phosphates. The layer in contact with molten metal contains 5-80 wt. % of at least one fluorine compound (as a corrosion resistant material) having a melting point of above 700.degree. C. Owing to the multiple layers, each having a specialized function, the casting apparatus has improved durability over a long period of time.

Casting apparatus for low-melting metals having two or more coating

A ceramic coating bonded to an iron tubular member comprising a bonding layer formed on a surface of the iron tubular member by a reaction of an iron tubular oxide layer of the iron tubular member and a silicate; and an iron oxide diffusion-preventing layer produced from fine metal oxide particles or an organometallic binder by firing on a surface of the bonding layer. The ceramic coating may further comprises an oxidation-preventing layer, a heat-insulating layer, a refractory layer or a thin dense protective layer. It may be produced by coating the surface of the iron tubular member with a silicate binder to form a layer which is then converted to a bonding layer by a heat treatment in a steam atmosphere; coating the surface of the bonding layer with fine metal oxide particles or an organometallic binder to form an iron oxide diffusion-preventing layer; and after curing and drying firing the resulting ceramic coating in an atmosphere having an oxygen partial pressure of 10 mmHg or less.

Ceramic coating bonded to iron member

A ceramic coating bonded to a metal member comprising a bonding layer formed by the reaction of an oxide layer formed on a surface of said metal member in advance and a silicated; and an anti-oxidizing first ceramic layer formed on said bonding layer and comprising inorganic flaky particles burned to have a cross-linked laminate structure.

Growing community of inventors

Fukuoka, Japan

Katsumi Morikawa