A casting apparatus for producing castings using molds each having a sprue, comprising a mold-conveying means for conveying molds each containing a melt poured through the sprue; nozzles each having a gas-introducing opening attachable to and detachable from the sprue; nozzle-attaching/detaching means each moving each nozzle to attach and detach the gas-introducing opening to and from the sprue; moving means for moving the nozzle-attaching/detaching means, such that the nozzle-attaching/detaching means moves following a mold conveyed by the mold-conveying means, while keeping the connection of the gas-introducing opening to the sprue by the nozzle-attaching/detaching means; and a gas supply means connected to each nozzle for supplying a gas to the gas-introducing opening.

A continuous casting process of a steel semi-product is provided. The process includes a step of casting using a hollow jet nozzle located between a tundish and a continuous casting mould. The nozzle includes, in its upper part, a dome for deflecting the liquid metal arriving at the inlet of the nozzle towards the internal wall of the nozzle, defining an internal volume with no liquid metal. A simultaneous step of injecting powder through a hole of the dome occurs. The powder has a particle size of 200 ?m or less. The dome includes a first device to inject the powder without any contact with the dome and a second device to avoid sticking or sintering of the powder onto the first device.

A continuous casting process of a steel semi-product is provided. The process includes a step of casting using a hollow jet nozzle located between a tundish and a continuous casting mould. The nozzle includes, in its upper part, a dome for deflecting the liquid metal arriving at the inlet of the nozzle towards the internal wall of the nozzle, defining an internal volume with no liquid metal. A simultaneous step of injecting powder through a hole of the dome occurs. The powder has a particle size of 200 ?m or less. The dome includes a first device to inject the powder without any contact with the dome and a second device to avoid sticking or sintering of the powder onto the first device.

A continuous casting process of a steel semi-product is provided. The process includes a step of casting using a hollow jet nozzle located between a tundish and a continuous casting mould. The nozzle includes, in its upper part, a dome for deflecting the liquid metal arriving at the inlet of the nozzle towards the internal wall of the nozzle, defining an internal volume with no liquid metal. A simultaneous step of injecting powder through a hole of the dome occurs. The powder has a particle size of 200 ?m or less. The dome includes a first device to inject the powder without any contact with the dome and a second device to avoid sticking or sintering of the powder onto the first device.

A continuous casting process of a steel semi-product is provided. The process includes a step of casting using a hollow jet nozzle located between a tundish and a continuous casting mould. The nozzle includes, in its upper part, a dome for deflecting the liquid metal arriving at the inlet of the nozzle towards the internal wall of the nozzle, defining an internal volume with no liquid metal. A simultaneous step of injecting powder through a hole of the dome occurs. The powder has a particle size of 200 ?m or less. The dome includes a first device to inject the powder without any contact with the dome and a second device to avoid sticking or sintering of the powder onto the first device.

A method for maintaining the optimal argon injection flow rate which will result in production of steel slab of a chosen alloy having optimal cleanliness. The steel is cast using an argon injected slide gate. The selected steel has a known optimal argon injection flow rate Qb* for casting steel of optimal cleanliness. The method involves calculating the present steel pressure and determining the present injection flow rate conductance Gb of the argon injected slide gate during either of 1) a steel pressure change event; or 2) an argon flow change event. The measurements are used to calculate present argon pressure required to insure the required injection flow rate of argon into the steel for optimal cleanliness of the cast steel.

A method for maintaining the optimal argon injection flow rate which will result in production of steel slab of a chosen alloy having optimal cleanliness. The steel is cast using an argon injected slide gate. The selected steel has a known optimal argon injection flow rate Qb* for casting steel of optimal cleanliness. The method involves calculating the present steel pressure and determining the present injection flow rate conductance Gb of the argon injected slide gate during either of 1) a steel pressure change event; or 2) an argon flow change event. The measurements are used to calculate present argon pressure required to insure the required injection flow rate of argon into the steel for optimal cleanliness of the cast steel.

A casting apparatus for producing a casting by pouring a metal melt into a gas-permeable casting mold by gravity, comprising: a gas-permeable casting mold comprising a cavity including a sprue composed of a tubular portion and a cup portion having a larger diameter than that of the tubular portion to receive the metal melt, a runner constituting a flow path of the metal melt supplied through the sprue, and a product-forming cavity to be filled with the metal melt sent through the runner; a means for pouring the metal melt into the sprue by gravity; a gas-blowing unit comprising a gas-ejecting member to be connected to the sprue; and a mechanism for moving the gas-ejecting member; the gas-ejecting-member-moving mechanism placing the gas-ejecting member at a position just above the tubular portion and not interfering with gravity pouring of the metal melt, and moving it downward for connection to the tubular portion; the gas-blowing unit having blowing a gas to fill the product-forming cavity with the metal melt.

A casting apparatus for producing a casting by pouring a metal melt into a gas-permeable casting mold by gravity, comprising: a gas-permeable casting mold comprising a cavity including a sprue composed of a tubular portion and a cup portion having a larger diameter than that of the tubular portion to receive the metal melt, a runner constituting a flow path of the metal melt supplied through the sprue, and a product-forming cavity to be filled with the metal melt sent through the runner; a means for pouring the metal melt into the sprue by gravity; a gas-blowing unit comprising a gas-ejecting member to be connected to the sprue; and a mechanism for moving the gas-ejecting member; the gas-ejecting-member-moving mechanism placing the gas-ejecting member at a position just above the tubular portion and not interfering with gravity pouring of the metal melt, and moving it downward for connection to the tubular portion; the gas-blowing unit having blowing a gas to fill the product-forming cavity with the metal melt.

A gas injected upper tundish nozzle including: a protective can; a ceramic inner portion disposed within the protective can, the ceramic inner portion having gas flow pathways therein; a gas injection port attached to the protective can allowing for the injection of gas through the protective can and into the gas flow pathways within the ceramic inner portion. A gas flow seal is formed between the protective can and the ceramic inner portion. The gas flow seal blocks gas leakage from the gap between the protective can and the ceramic inner portion. The gas flow seal is formed of nickel or an alloy of nickel.