Abstract: A projecting construction apparatus for a molten-metal-discharging hole includes a rotating shaft and an impeller rotatably supported by the end of the rotating shaft. The impeller has vanes radially disposed and is open to fluid flow in a generally axial direction, such that gas flowing axially toward the impeller can pass substantially axially through the impeller without being deflected against a wall of the hole, while liquid and solid material are deflected by the vanes against the wall of the hole. At least two material-supplying pipes are located around the rotating shaft, and are connected to supply projection material entrained in a fluid to the impeller, and have ejection ports generally equi-angularly disposed about the shaft axis. The ejection ports are directed toward the vanes, and a plurality of control valves are connected to respective ones of the pipes so as to control an amount of the projection material which is supplied to each of the pipes.

Abstract: An impeller as used in a projecting construction apparatus for a concave section of a molten-metal-discharging hole is supported on a rotating shaft for redirecting flow of impinging projection material. The impeller includes a plurality of vanes which are attached to the rotating shaft with a specified twisting angle relative to the rotating shaft. A material supplying pipe is directed upon the plurality of vanes, so that, upon impingement of the projection material upon the plurality of vanes, the projection material is projected outwardly and in a direction nearly opposite to the predetermined direction of impingement of the projection material supplied through the material-supplying pipe.

Abstract: 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.

Abstract: An apparatus for continuously measuring temperatures of molten metal including a thermocouple unit (A) and an immersion protection tube unit (B), wherein the thermocouple unit (A) comprises a thermocouple (1) having an end equipped with a temperature sensing element (8) and an opposite end connected to terminals (2), an insulator (9) of substantially one piece containing the thermocouple (1), a porcelain protection tube (6) of high airtightness containing the insulator (9), and a terminal box (3) having an extension sleeve (5) with which the upper part of the porcelain protection tube (6) is held and having a housing (20) which contains the terminals (2). The immersion protection tube unit (B) comprises an alumina-graphite protection tube (21), a holding sleeve (22) with a flange which is connected to the upper part of the alumina-graphite protection tube (21), and a connecting sleeve (26) connected with the holding sleeve (22).

Abstract: 2 to 15 wt % of a resin is added to a mixture of a refractory aggregate and a metal having a melting point of not higher than 1,000.degree. C., the resin being obtained by added 10 to 90 wt % of a silicon resin to at least one kind of thermosetting resin which easily exhibits a higher mechanical strength when heated to about 150.degree. to 250.degree. C. The resultant mixture is molded and heated to a temperature of not higher than 1,000.degree. C., thereby producing a high-durability plate brick for a sliding gate nozzle apparatus.

Abstract: Erosion or corrosion that has been caused during pouring a molten steel through a sliding gate nozzle for continuous casting becomes very serious when a specially treated molten steel such as deoxidized steel with a Ca alloy is applied for continuous casting. Such erosion can be eliminated by partially arranging a zirconia base refractory material on a portion of the inner surface of the nozzle hole. The zirconia base refractory material is composed of more than 53% by weight of partially stabilized zirconia base refractory material having less than 10 mesh grain size, 1 to 7% by weight of metallic silicon powder having less than 100 mesh grain size and 3 to 10% by weight of carbon powder.

Abstract: A process is disclosed for making a casting nozzle wherein gas can be blown out through the outlet of the nozzle to prevent the sticking of nonmetallic impurities to the nozzle during use. Reticulate organic filaments in the form, e.g., of a net are applied around a preformed inner cylindrical refractory body having a pouring hole therein. An outer cylinder body is then formed around the inner cylinder body including the organic filaments. The entire body is then fired, whereby the organic filaments carbonize and evaporate, leaving a network of gas-permeable reticulate holes in the body. An outlet is drilled or cut in the fired body through the gas-permeable holes to the pouring holes. Accordingly, when the nozzle is in use, a blowing gas can be provided through the reticulate holes to the nozzle outlet to prevent the sticking of nonmetallic impurities.

Abstract: An interior coating material for continuous caster tundishes which consists of a mixture of 5 to 60% by weight of a lightweight magnesia aggregate having a bulk density of 2.0 or less, and 40 to 95% by weight of an aggregate which is one or more substances selected from the group consisting of electrically molten magnesia clinker, seawater magnesia clinker, burnt clinker prepared from natural magnesite, dolomite clinker and spinel clinker, plus binder, hardening agent and fibers.

Abstract: A shaped body of silicon nitride enjoying high density, ample shrinkage, and outstanding mechanical strength is produced in a desired pattern by a method of preparing a shaped body comprising Si particles and a compound capable of remaining as SiC or C in the form of film on the surface of the Si particles in a non-oxidative atmosphere at a temperature in the range of 900.degree. to 1,400.degree. C., subjecting the shaped body to sintering and shrinkage of not less than 1% in an atmosphere of inert gas at a temperature exceeding 900.degree. C., and not exceeding the softening point of Si, and subsequently subjecting the resultant sintered shaped body to nitriding in a nitriding atmosphere at a pressure exceeding atmospheric pressure and at a temperature in the range of 1,200.degree. to 1,500.degree. C.

Abstract: A complex-shaped bonded body of silicon nitride having a high bonding strength of more than 30 kg/mm.sup.2 as flexural strength and continuously homogenous microstructure through the bonded portion can be obtained by the method comprising the following five steps:(a) molding a body from a mixture of silicon powder having a diameter of less than 44 .mu.m and non-oxide ceramics powder having a diameter of less than 44 .mu.m,(b) heating a molded body obtained by step (a) at a temperature of 600 to 1500.degree. C. in a non-oxide atmosphere such as nitrogen or argon gas to sinter said silicon powder and partially convert to silicon nitride retaining 60 to 100 wt. % unreacted silicon powder therein,(c) grinding a surface to be bonded together with other bodies of said presintered body obtained by step (b) to dispose of unreacted silicon thereon,(d) placing a bonding agent containing silicon powder having a diameter of less than 44 .mu.

Abstract: A casting nozzle designed such that the sticking of nonmetallic impurities to the outlet of the nozzle is prevented by blowing out a gas. The casting nozzle comprises a nozzle proper, an annular hollow chamber for gas blowing formed in the axial direction of the nozzle proper, and annularly arranged reticulate small holes for gas blowing communicating with the annular hollow chamber, the small holes opening at the outlet of the nozzle. The reticulate small holes are formed when organic filaments wound round a portion of the inside wall of the nozzle proper carbonize, volatilize, or shrink upon heating.

Abstract: Alumina-carbon-based refractory plates for the sliding nozzle are produced from alumina powder and carbon powder of specific particle diameter, in addition to the conventional refractory materials. The plates are durable and have good resistance to molten steel because of a compact structure which prevents the sticking of molten steel.

Abstract: A process for producing a silicon carbide sintered product, particularly, large-shaped silicon carbide sintered product by reaction sintering. Siliciding reaction can be carried out completely in a short period of time by adding an organic silicon polymer whose skelton is composed of silicon and carbon to the starting sintering material and using the same for the control of the reaction rate.

Abstract: Erosion-resistant silicon carbide composite sintered material, produced from starting materials composed mainly of SiC and also containing ZrB.sub.2 added thereto in an amount up to 50 volume %, resist penetration of, and erosion by, molten metals (such as molten steel) and show high erosion resistance, while retaining the outstanding characteristics unique to silicon carbide, such as high resistance to oxidation, creep and abrasion, and high mechanical strength and impact resistance at high temperatures. Thus the products can be advantageously used as protective pipes for molten metals, crucibles, rollers, nozzles, dies, blow pipes, agitator blades, rotating shafts, inner linings and other structural members which are to be used while in contact with molten metals (particularly molten steel) or other high-temperature metal parts. The corrosion resistance is particularly outstanding when the sintered materials additionally include metallic aluminum or an aluminum compound such as Al.sub.4 C.sub.3, AlN, AlB.

Abstract: An apparatus for changing casting nozzles such as immersion nozzles easily, quickly, and reliably.

Abstract: The application by spraying on a ceramic furnace wall of a refractory spray material prepared by mixing a spray powder consisting of 100 pts. wt. a refractory aggregate of a predetermined particle size and 0.1-3 pts. wt. a curing accelerator with 0.5-5 pts. wt. a damping agent added thereto is accomplished with notably high levels of adhesiveness and uniformity without deteriorating the working environment with dust by a method which comprises performing said application while admixing the refractory spray material with a sodium silicate solution as a binder having a viscosity in the range of 3-10 cPs at 15.degree. C. and containing 2-8 wt. % Na.sub.2 O and 8-20 wt. % SiO.sub.2.

Abstract: A method of manufacturing a ceramic body having continuous three-dimension through-out holes which can be preferably employed as a filter for filtration of non-metallic inclusions in a molten metal and as a porous plug for introducing a gaseous medium for floating up the non-metallic inclusions. An organic body having a three-dimensional construction is placed in a casting mold, a slip of a ceramic material is poured into the mold, and after drying, the molded body is baked to effect decomposition of the organic porous body. Thus the ceramic body is provided with through-out holes communicating with to each other three-dimensionally together with a high mechanical strength.

Abstract: A sliding nozzle apparatus for a molten metal holding vessel including a fixed nozzle member and a fixed plate therefor which are supported by an upper or fixed bracket secured to the vessel, and a movable nozzle member and a slidable plate therefor which are supported by a lower or movable bracket having one edge hinged to the upper bracket, while its opposite edge remote from its hinged connection to the upper bracket is removably connectable to the upper bracket to bring the slidable plate into contact with the fixed plate. A first set of coil springs are located adjacent to the edge of the lower bracket at which it is hinged to the upper bracket, and a second set of coil springs are located adjacent to the opposite edge of the lower bracket. The first set of coil springs are deflected to a greater degree than the second set of coil springs, or are, in other words, preloaded differently from the second set of springs.

Abstract: Method produces reaction sintered silicon nitride complex shapes. Parent material (moldings of silicon powder-cured resin) and bonding or joint material (silicon powder-uncured resin) are integrally connected by steps of heat-curing the resin in the joint, heating the body thus bonded together to pyrolyze the cured resin and sinter the silicon powder, the pyrolysis gas reducing oxide film on silicon, and sintered parent material and joint material are simultaneously nitrided and integrally connected by continuous silicon nitride.

Abstract: After sintering, ceramic body of Si.sub.3 N.sub.4 -SiC is heat-treated at 500.degree.-1500.degree. C. in atmosphere of gas mixture of chlorine and nitrogen whereby SiC is converted into silicon chloride which in turn is nitrided to form Si.sub.3 N.sub.4 in the pores of the ceramic body to provide closed pore structure. Gas mixture may contain oxygen. Heat treatment may be conducted in pressurized atmosphere of gas mixture.