Disclosed is a casting nozzle intended to suppress or prevent breaking of a nozzle body thereof. The casting nozzle comprises: a nozzle body; a metal casing disposed to surround an upper end of the nozzle body to form a gas pool between an outer peripheral surface of the upper end of the nozzle body and an inner peripheral surface of the metal casing; and a bridging segment provided in at least a part of the gas pool to bridge between the outer peripheral surface of the upper end of the nozzle body and the inner peripheral surface of the metal casing.

A thin slab nozzle contains a central bore extending downstream along longitudinal axis X1 from an inlet orifice at an upstream end. The central bore comprises an upstream bore portion with a height Ha, in communication with a converging bore portion of height He, in communication with a thin bore portion of height Hf ending at the upstream end of a divider, and first and second front ports separated from one another by the divider and coupled to the central bore portion at least partially at the converging bore portion. X2 is a transverse axis, normal to X1, along which the nozzle becomes thinner in a downstream portion. In a section of the thin slab nozzle along a symmetry plane 1 defined by X1 and by X2, the bore wall of the converging bore portion is curved at all points, and Hf/He1.

A thin slab nozzle contains a central bore extending downstream along longitudinal axis X1 from an inlet orifice at an upstream end. The central bore comprises an upstream bore portion with a height Ha, in communication with a converging bore portion of height He, in communication with a thin bore portion of height Hf ending at the upstream end of a divider, and first and second front ports separated from one another by the divider and coupled to the central bore portion at least partially at the converging bore portion. X2 is a transverse axis, normal to X1, along which the nozzle becomes thinner in a downstream portion. In a section of the thin slab nozzle along a symmetry plane 1 defined by X1 and by X2, the bore wall of the converging bore portion is curved at all points, and Hf/He1.

A plate, a plate-holding apparatus, and a holding method for the plate for facilitating work to attach the plate to a plate-receiving metal frame of a sliding nozzle device. A gap is ensured between a to-be-held portion of the plate and an inner wall surface of an engagement groove such that, when the plate is held by engaging the to-be-held portion of the plate with the engagement groove of a holding portion of the plate-holding apparatus, the plate is movable in the longitudinal direction, the width direction, and the thickness direction of the plate.

A plate, a plate-holding apparatus, and a holding method for the plate for facilitating work to attach the plate to a plate-receiving metal frame of a sliding nozzle device. A gap is ensured between a to-be-held portion of the plate and an inner wall surface of an engagement groove such that, when the plate is held by engaging the to-be-held portion of the plate with the engagement groove of a holding portion of the plate-holding apparatus, the plate is movable in the longitudinal direction, the width direction, and the thickness direction of the plate.

Disclosed is a refractory product for casting of steel, which is capable of forming a dense surface layer which is high in terms of a slag infiltration suppressing ability and strong, in a surface region thereof efficiently or sufficiently or in an optimum state. The refractory product contains 1 mass % or more of free carbon, and 2 mass % to 15 mass % of an aluminum component as metal, with the remainder comprising a refractory material as a main composition, wherein the refractory product has a permeability of 110.sup.16m.sup.2 to 1510.sup.16m.sup.2.

Disclosed is a refractory product for casting of steel, which is capable of forming a dense surface layer which is high in terms of a slag infiltration suppressing ability and strong, in a surface region thereof efficiently or sufficiently or in an optimum state. The refractory product contains 1 mass % or more of free carbon, and 2 mass % to 15 mass % of an aluminum component as metal, with the remainder comprising a refractory material as a main composition, wherein the refractory product has a permeability of 110.sup.16m.sup.2 to 1510.sup.16m.sup.2.

An opening-closing apparatus capable of, when using a robot arm to selectively open and close a component of a sliding nozzle device, reliably opening and closing the component to respective given positions. The apparatus comprises: a hand-like distal module engageable with an openable-closable component of a sliding nozzle device; a force sensor to detect a force received by the module; and a robot arm to which the module and the sensor are mounted. The robot arm is controllably operated to: move the module toward the component of the sliding nozzle device and engage the module with the component of the sliding nozzle device; then move the module to move the component, if the absolute value of the force detected by the sensor is equal to or less than a given threshold; and stop the movement of the module, when the absolute value of the force detected by the sensor reaches the threshold.

An opening-closing apparatus capable of, when using a robot arm to selectively open and close a component of a sliding nozzle device, reliably opening and closing the component to respective given positions. The apparatus comprises: a hand-like distal module engageable with an openable-closable component of a sliding nozzle device; a force sensor to detect a force received by the module; and a robot arm to which the module and the sensor are mounted. The robot arm is controllably operated to: move the module toward the component of the sliding nozzle device and engage the module with the component of the sliding nozzle device; then move the module to move the component, if the absolute value of the force detected by the sensor is equal to or less than a given threshold; and stop the movement of the module, when the absolute value of the force detected by the sensor reaches the threshold.

A method for casting a melt uses a melt container in which a melt receiving space is formed. The melt container has a spout in the form of a lance on the bottom on the melt container. The method includes the following steps: filling the melt container with melt, wherein the melt is introduced into the melt receiving space of the melt container from a crucible using a spout orifice of the lance; casting at least one cast workpiece with melt; filling the melt container with melt again. When filling the melt container with melt, more melt is received in the melt receiving space than is needed for casting the cast workpiece. Directly before the renewed filling of the melt container, a remainder of melt having an oxide skin formed at the melt surface is present in the melt receiving space of the melt container.