Patents Assigned to Harima Ceramic Co. Ltd.
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Patent number: 5559064Abstract: Chrome-free bricks which exhibit excellent resistance to corrosion, penetration, and thermal spalling. The bricks are mainly made from a magnesia material and/or a magnesia-alumina spinel material and comprise 1 to 10 wt % titania and 1 to 15 wt % alumina. They may contain 0.5 to 10 wt % iron oxide. Further, they may contain at least one material of the group consisting of 1 to 10 wt % metal powder, 1 to 20 wt % carbon and 1 to 20 wt % one of oxide materials except for iron oxide.Type: GrantFiled: December 30, 1994Date of Patent: September 24, 1996Assignee: Harima Ceramic Co., Ltd.Inventors: Akihiro Tsuchinari, Hiroaki Osaki, Hisato Okamoto, Tetsuo Yamamoto
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Patent number: 5506181Abstract: A refractory of the invention is used in casting operation, which has good spalling resistance and corrosion resistance. The refractory includes: 0.0357-2.6548 wt % of amorphous silica particles having a specific surface area within a range of 15-30 m.sup.2 /g; 8.8495-28.5612 wt % of alumina particles having a particle diameter within a range of 10-50 mm; 1.3986-18.1715 wt % of at least one of fused magnesia and sintered magnesia, which contains 0.6993-10.9041 wt % of magnesia having a maximum particle diameter under 44 .mu.m; 0.6993-13.630 wt % of alumina cement; and 45.4545-88.1417 wt % of alumina. When the refractory is used, at lease one of fused magnesia and sintered magnesia surrounds the alumina particles, which react together to generate spinel to thereby form micro-crack layer around the alumina particles for preventing propagation of cracks in a refractory structure.Type: GrantFiled: June 30, 1994Date of Patent: April 9, 1996Assignee: Harima Ceramic Co., Ltd.Inventors: Osami Matsumoto, Toshihiro Isobe, Syouichi Itose
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Patent number: 5204298Abstract: Basic monolithic refractories of which the chemical composition consists essentially of, in oxide equivalence, 65%-96% by weight of MgO, 2.6%-20% by weight of ZrO.sub.2, 1.3-10% by weight of SiO.sub.2, 2% or less by weight of CaO, 0.5% or less by weight of Fe.sub.2 O.sub.3 and 1% or less by weight of Al.sub.2 O.sub.3, and with a mineral composition containing periclase as the main component and cubic zirconia and forsterite as sub-components, and with apparent porosity of 7% or less and bulk density of 3.2 g/cm.sup.3 or more.Basic monolithic refractories under this invention possess excellent slaking resistance, slag erosion resistance, slag penetration resistance and spalling resistance. They exhibit an excellent service life, especially as lining material for steel-making furnaces.Type: GrantFiled: November 21, 1991Date of Patent: April 20, 1993Assignees: Harima Ceramic Co., Ltd., Krosaki Corporation, Nippon Steel CorporationInventors: Hideo Yaoi, Toshihiro Isobe, Yukihiro Suekawa
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Patent number: 5104833Abstract: A refractory for casting a basic substance comprises 100 parts by weight of a refractory aggregate having as main ingredients 3 to 40% by weight of zircon and 97 to 60% by weight of magnesia and a suitable amount of a binding agent. Another refractory for casting a basic substance comprises 100 parts by weight of a refractory aggregate having as main ingredients 3 to 40% by weight of zircon and 97 to 60% by weight of magnesia, not more than 7 parts by weight of metallic fibers, and a suitable amount of a binding agent. The refractories for casting a basic substance are used for ladles, tundishes, vacuum degasing furnaces, mixers, and the like.Type: GrantFiled: December 24, 1990Date of Patent: April 14, 1992Assignees: Harima Ceramic Co. Ltd., Nippon Steel CorporationInventors: Osami Matsumoto, Toshihiro Isobe, Hisashi Matsuoka, Yasuhisa Abe
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Patent number: 4990475Abstract: An alumina-spinel monolithic refractory consists essentially of 50-90 percent by weight of alumina clinker, 5-40 percent by weight of MgO--Al.sub.2 O.sub.3 spinel clinker not larger than 1 mm in size and 1-25 percent by weight of alumina cement. Another alumina-spinel monolithic refractory consists essentially of 50-90 percent by weight of alumina clinker, 5-40 percent by weight of MgO--Al.sub.2 O.sub.3 spinel clinker, 1-25 percent by weight of alumina cement and not more than 5 percent by weight of magnesia clinker. The alumina-spinel monolithic refractories are used for lining the inner walls of ladles, vacuum degassing vessels, hot-metal mixers, blast-furnace troughs and their covers, not-metal mixer cars, tundishes and the like.Type: GrantFiled: March 16, 1990Date of Patent: February 5, 1991Assignees: Harima Ceramic Co. Ltd., Nippon Steel CorporationInventors: Osami Matsumoto, Toshihiro Isobe, Teruyuki Nishitani, Takashi Genba