Abstract: The nozzle for continuous casting has a plurality of steps in the molten steel pouring hole of the nozzle. The dimension of the inside diameters of the steps to the inside diameter d of the main pipe is d.sub.1 >d.sub.2 >d or d.sub.1 >d.sub.2 d.sub.3 >d, the inside diameter d.sub.2 or d.sub.3 immediately above the molten steel pouring outlet is d+10 mm.gtoreq.d.sub.2 or d.sub.3, and the material of the inner peripheral wall near the pouring outlet is boron nitride-carbon.

Abstract: Alumina-spinel monolithic refractory having excellent spalling resistance, corrosion resistance and slag penetration resistance. The alumina-spinel refractory contains an alumina-spinel clinker having a MgO:Al.sub.2 O.sub.3 molar ratio ranging from 0.14:1.86 to 0.6:1.4 which can be simultaneously used with a spinel clinker having a close to theoretical composition with the balance consisting of an alumina material and alumina cement. Also, in order to inhibit the elongation of cracks an alumina crushed grain having a grain size ranging from 10 to 50 mm can be added to the alumina-spinel monolithic refractory.

Abstract: The present invention relates to a discharge regulator of molten metal, which can be disposed approximately vertically at the bottom portion of a molten metal vessel, characterized in that the regulator consists of a rotary nozzle, a nozzle carrying brick and a sleeve or of a rotary nozzle and a nozzle carrying brick, two or more recessed notches or openings are provided in at least either one of said nozzle carrying brick and said sleeve, the surface of said nozzle opening of the rotary nozzle, which pierces through at least one nozzle hole, is supported slidably to and in close contact with the inner peripheral surface of said nozzle carrying brick or said sleeve, and said rotary nozzle is equipped with a rotary mechanism mounted in such a manner that the upper portion of said rotary nozzle is brought into contact with the molten metal.

Abstract: A method which enables easy and efficient production of silica brick having small content of residual silica by firing from a siliceous stone material containing silica as the main component, even when the siliceous stone material used is of the type in which transformation of silica is not easy to occur. The method is characterized by adding 0.2 to 5 wt % of Na.sub.2 O--CaO--SiO.sub.2 fused and solidified material to the siliceous stone material. The Na.sub.2 O--CaO--SiO.sub.2 fused and solidified material, together with a binder, is added to pulverized siliceous stone material, and the mixture is then formed followed by a firing at 1350.degree. to 1500.degree. C., so that the Na.sub.2 O-13 CaO--SiO.sub.2 fused and solidified material reacts with silica in the siliceous stone material to promote transformation of the silica into cristobalite and tridymite.

Abstract: A plate brick for a sliding gate valve provides a mechanism for preventing cracks which may occur in the abutting portion of a brick setting metal fitting. The plate brick comprises ends having a semicircular shape and an outer periphery which is strained with an iron plate hoop. The generation of cracks is reduced by providing slits or recesses at both ends of the plate at positions corresponding to those of the brick fixing metal fittings.

Abstract: An exothermic type mold additive for continuous casting comprising 20.about.90 wt % base raw materials, 0.about.10 wt % silicious raw materials containing more than 50 wt % SiO.sub.2 content, 0.about.20 wt % flux raw materials, 2.about.30 wt % of more than one kind selected from a group comprising carbonates, bicarbonates and nitrates of alkaline metals as exothermic materials, and 3.about.30 wt % of more than one kind of component selected from a group comprising carbon, silicon and silicon alloys as reducing materials. Oxidation exothermic speed is controlled by controlling the kind and amounts of reducing materials, and casting with few carburization, inclusions, pin-holes, etc. can be obtained.

Abstract: This invention concerns an apparatus for enabling exchange of an immersion nozzle seated in a tundish and used for casting of a molten metal from a molten metal container to be carried out very easily and quickly, which apparatus comprises rails (4) laid so as to approximate closely to a molten metal casting outlet nozzle (2) of a molten metal container (1), a self-propelling truck (5) adapted to travel on the rails (4), retainer parts (7) mounted on the truck (5) and adapted to retain an immersion nozzle (3) at the leading terminal thereof, and a movable arm (6) provided with a cleaning device (18) for cleaning the lower terminal surface of the outlet nozzle (2) after removal of a used immersion nozzle.

Abstract: A mold additive suitable for use in a mold for continuous casting of steel which comprises, as its base material, at least 50% by weight of synthetic calcium silicate which contains CaO and SiO.sub.2 in a total amount not less than 70% by weight, and whose CaO/SiO.sub.2 ratio is not lower than 1.20. A mold additive of low bulk density and superior in heat insulation can be obtained and its CaO/SiO.sub.2 ratio can be widely adjusted.

Abstract: A laser beam-transmitting section of a laser measuring instrument of dimensional change is arranged at one side of a specimen heating furnace, a laser beam-receiving section is arranged at the opposide side of the furnace, a slit fixture for shielding within-the-furnace radiation heat and light is provided inside a measuring window, a heat insulating material having a slit for shielding within-the-furnace radiation heat and light is provided inside said slit fixture, and a within-the-furnace radiation light shielding slit plate and a within-the-furnace radiation light reducing optical filter are disposed at the end faces of said respective laser beam-transmitting section and said laser beam-receiving section whereby measuring errors caused by the light and heat generated within the furnace are prevented (the interior of a specimen heating furnace core pipe can be replaced by various kinds of atmospheres as necessary, and it is possible to measure the dimensional change of small-size specimens of ceramics or t

Abstract: A magnesia-alumina type spinel clinker contains Fe.sub.2 O.sub.3 and TiO.sub.2 at boundaries between crystal grains, and a refractory produced by using the clinker has excellent corrosion resistance and cement coating properties. The refractory can thus be applied to the fields of cement rotary kiln refractories, refractories for iron making, steel making and nonferrous refining and the like.

Abstract: Disclosed is an apparatus for observing the interior of a hot furnace. The apparatus is equipped with a camera arranged in a case whose inner surface is cooled by means of cooling water and into whose inner space cooling air is blown, the apparatus comprising: a quartz-glass plate, a heat-ray-reflecting-glass plate, a heat-ray-absorbing-glass plate, and a heat-ray-transmitting mirror arranged in order of decreasing distance to the camera in an optical path through which a ray of light entering at the front surface of the case is led to the camera; and an illuminating lamp which is provided on the front surface of the case and whose luminance can be remote-controlled. With this construction, the temperature in the camera case can be kept at 50.degree. C. or less, and damage to the camera due to the radiation heat entering through the glass window can be avoided. With this apparatus, the interior of a hot furnace can be observed over a temperature range of room temperature to 1200.degree. C.

Abstract: A carbon-containing refractory is formed by mixing 1-10 weight % of silicon nitride, 1-35 weight % of carbon, and a remainder of a refractory raw material, molding the mixture into a molded body, and burning the molded body such that fine whiskers of silicon carbide are uniformly distributed within the matrix.

Abstract: The present invention was developed to solve the problems inherent in conventional dry type and wet type gunning methods. The main point of the present invention is a novel method for gunning a refractory composition for obtaining a lining body having high density and high strength by premixing a refractory composition with water amounting to 1/5-3/4 of the total amount of water for the lining, and subsequently adding and mixing the rest of the water at the inside of the gunning nozzle of the dry gunning equipment while gunning.

Abstract: An opening element for an insert nozzle of a slide gate valve apparatus, wherein a dead weight having an outside diameter smaller than the inside diameter of the melt passage opening of the slide gate valve apparatus is connected to a refractory cap by means of a steel wire, or by a refractory or metallic coupling rod and a method of opening said slide gate valve apparatus wherein said opening element is set in said respective passage openings of the insert nozzle and of a bottom plate connected to the nozzle, and said opening element is opened by the impact load exerted when said dead weight falls down due to the opening of the slide gate valve apparatus.

Abstract: The present invention provides a two layered refractory plate consisting of a crack-resistant substrate with a grained surface layer embedded thereon. This two layered refractory plate is suitable for use as a shelf plate in a furnace in which the temperatures vary. Cracks due to thermal expansion differences in the material can be prevented.

Abstract: The present invention offers a mould additive for continuous casting of steel characterized by having a fully spherical shape in which average particle size is in the range of 100 to 800 .mu.m.

Abstract: A clamping and fixing apparatus of a refractory-made plate 7 for a slide gate valve for controlling a molten steel flow comprising:providing plate-clamping fixtures 12, 12 rotatably in its plane direction and in contact with the inner side of a casing 13 and a guide piece 11, at both the ends at the plate side, of the guide piece 11 being supported by at least one guide 16 provided within the longer edge sides of the casing 13 which houses the refractory-made plate 7;inserting idly a nut 10 into a dovetail groove recess 11a provided in the other area of said guide piece 11;mounting to said nut 10 a bolt 9 which is rotatable passing through said casing 13; andproviding said fixtures 12, 12 with respective surfaces of contacting the plate 7.

Abstract: A carbon containing refractory comprising, by weight: 5 to 60% of AZT clinker mainly constituted by ZrO.sub.2, Al.sub.2 O.sub.3, TiO.sub.2 and SiO.sub.2 ; 3 to 40% of a carbon source; and the balance being at least one or two refractories selected from a group consisting of alumina, magnesia, zirconia, mullite, spinel, calcia, and fused quartz.

Abstract: The present invention resides in the provision of a basic unburned brick or castable refractory which contains none or an extremely small amount of components which exert a harmful influence on molten steel such as phosphorus, sulfur, and boron and which has a high hot strength.

Abstract: Disclosed herein is a porous nozzle which is made up of an upper porous brick, a dense brick, and a lower porous brick arranged vertically in layer and a casing surrounding them. The casing is provided with an inert gas supply pipe which leads to the peripheral space of the upper porous brick. The casing is also provided with another inert gas supply pipe which leads to the peripheral space of the lower porous brick.Disclosed also herein is another porous nozzle which is made up of an upper porous brick, a dense brick, and a lower porous brick arranged vertically in layer and a casing surrounding them. The casing is provided with an inert gas supply pipe which leads to the peripheral space of the lower porous brick which communicates with the peripheral space of the upper porous brick.