Abstract: A melt is stored in a vessel, and a lower half portion of a rod-formed porous member is immersed in the melt. The porous member is made of a porous material having pores which is permeable to gas and impermeable to melts, such as molten metal, molten slag, and molten matte. When the vessel is placed in a decompression container and the portion of the porous member which protrudes above a surface of the melt is put in vacuum or under reduced pressure, gases in the melt or gases produced by reactions between components of the porous member and the melt pass through pores of the porous member and are released to vacuum or depressurized atmosphere in the decompression container. Thus, gas-forming components are removed from the melt.

Abstract: A pressure-casting machine that contains a delivery system, which comprises: a molten metal pouring pipe made of a refractory, having a length of at least 4 m and an outside diameter of at least 350 mm, and arranged such that an upper end thereof is attached substantially vertically from below to an opening in a bottom wall of a mold for a pressure-casting machine, and a lower end thereof extends through a lid of a closed vessel arranged below the mold and is immersed into molten metal received in a ladle arranged in the closed vessel. The molten metal pouring pipe comprises at least two pipe sections connected to each other in series and in a liquid-tight manner by means of a threaded joint, tapered surfaces provided with screw threads of which have an inclination angle within a range of from 2.0.degree. to 15.0.degree. relative to the center axis of the molten metal pouring pipe.

Abstract: A melt is stored in a vessel. A lower half of a degassing member is immersed in the melt. The degassing member has a cylindrical form with the lower end closed, and the lower half section is made of a porous material which is permeable to gas and impermeable to melts as molten metal, molten slag, or molten matte. This lower half section is a partitioning member. When an internal space inside the degassing member is sucked to realize vacuum or reduced pressure atmosphere, gas producing components in the melt pass through the partition member of the degassing member, and are exhausted to inside the degassing member, thus being separated from the melt. Also, by making the degassing member rotate or move in a horizontal or vertical direction, the melt is stirred. With these features, gas-producing components in the melt can be removed at a high efficiency.

Abstract: A melt is stored in a vessel placed in a decompression vessel. On the bottom of the vessel is arranged a bubble generator made of porous bricks, and bubbles of argon gas are introduced into the melt through this bubble generator. Also a lower half section of a degassing member is immersed in the melt. This degassing member has a cylindrical form with the lower end closed and the section immersed in the melt is made of a porous material permeable to gases and impermeable to melts.With these features, a surface of molten metal can be put under reduced pressure and high content components of the melt can be removed by means of bubbling, and also solute components in the melt can be removed into bubbles of argon gas. Also, gases in the melt and gases produced by reactions between the melt and the porous material can be sucked through a wall of the degassing member into inside thereof and removed.

Abstract: A refractory for gas blowing to be attached to an opening of a molten metal refining vessel includes a gas permeable portion comprising an alumina refractory, the gas permeable portion having a plurality of gas blowing apertures running therethrough in the axial direction thereof, and a collar portion comprising an alumina refractory, formed integrally with the gas permeable portion so as to surround the gas permeable portion. The alumina refractory for both the gas permeable portion and the collar portion contains at least 88 wt. % alumina and is substantially non-porous with a porosity of up to 20%.

Abstract: A valve of a faucet comprises a stationary disk and a rotary disk. Each of the stationary disk and the rotary disk is made of a ceramics or a metal, and one surface of the stationary disk and one surface of the rotary disk are in contact with each other to form a sliding face therebetween. The valve of the faucet opens and closes a passage of a liquid by means of a relative displacement of the stationary disk and the rotary disk along the sliding face to control the flow rate of the liquid. At least one of the one surface of the stationary disk and the one surface of the rotary disk, which form the sliding face, has a film substantially comprising diamond-like carbon thereon.

Abstract: In a rotary nozzle of the type attached to the bottom shell of a molten street vessel and designed so that a rotor having a sliding plate brick mounted thereon is rotated by a motor through a reducer and gearing to adjust the degree of opening of a nozzle bore and thereby to control the pouring rate of molten steel, the rotation of the rotor is effected by hydraulic cylinders in place of the reducer, gearing and motor. Thus, there is the effect of providing a rotary nozzle which is small in size, light in weight and low in cost.

Abstract: A door opening/closing device of door-type rotary nozzle which cannot fit collector nozzle (16) unless clampers are removed. There is no possibility of pouring molten metal while forgetting to remove the clampers (25). When the fixed frame (7) is opened or closed, a ladle is fitted by a 90 degree angle with its bottom almost vertical. So, the fitting and removing operations of the clampers (25) can be performed in front of an operator, which makes the operation very easy.

Abstract: A rotary nozzle in which at least one coil spring is removed, acting to increase the clearance between a surface of the bottom plate brick and a surface of the slide plate brick. This mechanism is capable of improving the pushing force in the vicinity of the nozzle hole, and prevents molten steel leakage, thus prolonging the life of expensive bricks.

Abstract: A magnesia aggregate for a refractory article, which comprises: a core portion comprising magnesia; a covering layer excellent in slag penetration resistance, which comprises a refractory material excellent in slag penetration resistance and covers the surface of said core portion; and an intermediate layer excellent in slag penetration resistance, formed between said core portion and said covering layer through combination thereof. Said magnesia aggregate is manufactured by: forming, on the surface of a core portion which comprises magnesia and has a particle size of from 40 .mu.m to 10 mm, a covering layer which comprises a powdery refractory material excellent in slag penetration resistance and has a covering thickness of from 20 .mu.m to 2.0 mm, to prepare a green aggregate; and firing said green aggregate at a temperature of from 1,700.degree. to 2,200.degree. C.

Abstract: A rotary nozzle system attached to the outlet of a metallurgical vessel to serve as a gate valve for controlling the rate of pouring of molten metal. A slide plate brick and bottom plate brick, each having a nozzle bore, are relatively rotated in a surface-to-surface contact condition to adjust the degree of communication opening of the nozzle bores. Each of the plate bricks is formed on the outer peripheral surface thereof with a flat portion for receiving the driving force for the relative reaction force at each of four locations arranged at angular intervals of 90.degree..

Abstract: A leg is fitted through a joint material into each of a pair of vertical openings on a bottom wall of a vacuum tank for refining molten steel, for protecting the vertical openings from molten steel. The abovementioned leg has an annular inner wall formed by piling up through a joint material a plurality of magnesia-chrome fired radial bricks in a plurality of horizontal annular rows arranged one on the other so as to form an inner bore for passing molten steel therethrough. The leg also has an annular outer wall formed by piling up through a joint material a plurality of magnesia-chrome fired radial bricks in a plurality of horizontal rows arranged one on the other so as to cover substantially the entire outer surface of the annular inner wall. The inner surface of the annular outer wall is in contact with the outer surface of the annular inner wall through a joint material.

Abstract: In a dual door type rotary nozzle system for metallurgical vessels, a bottom plate brick attached to the bottom shell of the vessel is adapted to be opened and closed by an inner door, and a slide plate brick slidable in surface-to-surface contact relation with the bottom plate brick is also adapted to be opened and closed by an outer door. The bottom plate brick is provided with a plurality of nozzle bores and is mounted in a case rotatably supported in the inner door by means of a bearing so that the bottom plate brick is manually rotated along with the case when the inner door is opened, thereby realizing a rotary nozzle system capable of easily and rapidly effecting the change operation of the nozzle bores of the bottom plate brick.

Abstract: A rotary nozzle engageable with the pouring nozzle of a ladle that contains molten metal for transporting or pouring purposes, or in the flow passage of a converter so as to allow the outflow of molten metal. The rotary nozzle includes a fixed plate brick, a fixed plate supporting frame, a rotor mounted on the outer periphery of the supporting frame by way of a bearing, and a sliding plate supporting frame holding a sliding plate brick secured to the rotor by means of a hinge so that it can be hingedly opened and closed. Hooks and spring means are carried by the sliding plate supporting frame to thereby prevent lowering of the sliding plate brick and to securely fasten the sliding plate supporting frame to the rotor. Cooperating lugs are carried by a door frame and by the sliding plate supporting frame and hydraulic jacks serve to draw the lugs together to maintain the door frame and the sliding plate supporting frame together when the hooks are released.

Abstract: A sliding rotary nozzle assembly for pouring of molten steel has a bottom plate brick and a sliding plate brick, with these plate bricks being arranged as dual doors that may be opened and closed as desired relative to a base plate that includes a flow nozzle. Each of the brick plates is provided with plural nozzle openings and is carried for rotation with the bottom plate brick being positioned on top of the sliding plate brick when the doors are closed. In case of damage to nozzle opening of the rotary bottom plate brick, the dual doors are opened and the bottom plate brick is then rotated to bring the remaining nozzle opening to the use position to make best use of the bottom plate brick and prolong the service life of the nozzle assembly.

Abstract: A slide closure for the pouring nozzle of a molten metal vessel of the type comprising a fixed plate attached to the bottom portion of the vessel and a sliding plate pressed against the lower surface of the fixed plate brick, whereby the sliding plate is rotated to open and close the vessel pouring nozzle, and further comprising a supporting member or rotor adapted to be rotated with the sliding plate brick as a unit by a driving source and supporting means for slidably supporting the rotor and pressing the sliding plate brick against the fixed plate brick with a vessel bed plate serving as a supporting point, characterized in that said supporting means comprises a first supporter for surrounding and slidably supporting the rotor and a second supporter fastened to the vessel bed plate by means of pins with a dish spring interposed between the second supporter and the lower side of the annular projection of the first supporter to enclose the latter whereby the second supporter urges the first supporter upwardl

Abstract: A method for blowing a gas from below into a molten steel in a refining vessel, which comprises: using a refining vessel including at least one gas blowing aperture provided in the bottom wall thereof and a frustoconical plug matching with said aperture, releasably inserted into said gas blowing aperture, which has a small-diameter bore having a diameter within the range of from 0.5 to 6.

Abstract: A brick for a slide closure of a vessel for holding molten metal. The brick is made by forming and then subjecting to reducing-burninng a compound comprising an acid or neutral refractory material as a base material, graphite and a binding agent.