Abstract: A device, e.g., a stirring plug or a mono-block stirring plug and pocket block set, for introducing gas into a mass of molten metal. The devices each have a body formed of a first refractory material. The stirring plug has plural V-shaped, gas carrying slots extending therethrough, while the mono-block set includes plural helical passageways extending therethrough. A wear indicator comprising a thin walled, thermally insulative tube having a central core of a second refractory material of a different coefficient of light emission but similar coefficient of thermal expansion to the first material is disposed within a central recess in the body adjacent either the top or the bottom end of the device. The wear indicator extends towards an intermediate point representing the remnant height of the device.

Abstract: A gas stirring plug for introducing gas into a mass of molten metal. The plug is a generally frusto-conical shaped member which is worn away during use and which should be replaced when it has worn away to a predetermined point and comprises a shell, a core, and a low melting point component disposed within a cavity in the core. The core is located within the shell and is comprised of a refractory material extending between the bottom end and the top end of the plug. The cavity is of a predetermined height and has a bottom located a first predetermined distance above the bottom end of the plug. The cavity is filled with the low melting point component, e.g., soapstone, calcium silicate, talcum, or some other material having a melting point lower than steel, from its bottom to an intermediate point located a predetermined height above the bottom of the cavity. Mortar or some other high melting point refractory component is disposed in the cavity from the intermediate point to the top of the plug.

Abstract: A low tolerance joint connecting a pair of hollow refractory bricks, e.g., center riser bricks, runner bricks, etc., together for carrying molten metal, e.g., steel, therethrough. Each brick has a pair of ends with a central passageway extending therebetween. One end of one brick comprises a conical walled annular flange projecting therefrom and a shoulder extending about the annular flange. One end of the other brick comprises a matingly shaped circular recess and shoulder extending about the circular recess. The joint comprises the interface between the adjacent surfaces of the annular flange and recess when the flange is located therein. The interface thus formed is an elongated space, free of mortar or other sealing material, into which the molten metal flows to freeze therein and thereby form a seal precluding its egress from the passageway to the ambient surroundings.

Abstract: An improvement in a slide gate for a container holding molten metal comprising a slide housing and refractory bodies made of a refractory composition, which refractory bodies have been impregnated with carbon-containing media, the improvement residing in employing as the carbon-containing medium an oil containing less than 10% by weight pitch.

Abstract: A head or slide plate for a molten-metal slide gate is formed by a refractory plate having an opening and a refractory ring positioned in the opening, with a ring of tar between the peripheries of the opening and refractory ring and which is isolated from the plate surfaces excepting for a passage filled with a porous refractory and through which the vaporized tar migrates to one of the slide surfaces when the plate and ring are heated by contact with the molten metal.