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.

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.

In a continuous casting device 100 for casting a stainless steel billet 3c, a long nozzle 2 extending into a tundish 101 is provided at a ladle 1. A molten stainless steel 3 is poured through the long nozzle 2 into the tundish 101, and a spout 2a of the long nozzle 2 is immersed into the poured molten stainless steel 3. During pouring, an argon gas 4a is supplied around the molten stainless steel 3 in the tundish 101. Further, continuous casting is performed, in which, while immersing the spout 2a of the long nozzle 2 into the molten stainless steel 3 in the tundish 101, the molten stainless steel 3 is poured from the ladle 1 into the tundish 101 and poured from the tundish 101 into a casting mold 105. During casting, a nitrogen gas 4b is supplied instead of the argon gas 4a around the molten stainless steel 3 inside the tundish 101.

A leak-proof gas injected upper tundish nozzle including a protective can, and a ceramic inner portion disposed within the protective can. The ceramic inner portion may has gas flow pathways therein which have been formed using a sacrificial mold when producing the ceramic inner portion. A gas flow seal is formed on the interior surfaces of the gas flow pathways within the ceramic inner portion. The gas flow seal blocks gas leakage from the gas flow pathways into any cracks in the ceramic inner portion. The gas flow seal is formed of nickel or an alloy of nickel.

A leak-proof gas injected upper tundish nozzle including a protective can, and a ceramic inner portion disposed within the protective can. The ceramic inner portion may has gas flow pathways therein which have been formed using a sacrificial mold when producing the ceramic inner portion. A gas flow seal is formed on the interior surfaces of the gas flow pathways within the ceramic inner portion. The gas flow seal blocks gas leakage from the gas flow pathways into any cracks in the ceramic inner portion. The gas flow seal is formed of nickel or an alloy of nickel.

An immersion nozzle for continuous casting is adapted to discharge molten steel into a mold for continuous steel casting and has a tubular nozzle body which is provided with four molten steel discharge ports consisting of left upper, left lower, right upper and right lower ports which open into a lower end portion of the nozzle body to be immersed into the molten steel in the mold. The two left discharge ports and the two right discharge ports have substantially symmetrical shape with respect to an axis of the nozzle. The left discharge ports are opposed to the inner wall of the left minor side of the mold and the right discharge ports are opposed to the inner wall of the right minor side of the mold. The area of the openings of the lower discharge ports is smaller than the area of the openings of the upper discharge ports. The ratio of the area of the openings of the lower discharge ports to the area of a sum of the areas of the openings of the upper and lower discharge ports is not less than 0.2 but not more than 0.4.

An immersion nozzle for continuous casting is adapted to discharge molten steel into a mold for continuous steel casting and has a tubular nozzle body which is provided with four molten steel discharge ports consisting of left upper, left lower, right upper and right lower ports which open into a lower end portion of the nozzle body to be immersed into the molten steel in the mold. The two left discharge ports and the two right discharge ports have substantially symmetrical shape with respect to an axis of the nozzle. The left discharge ports are opposed to the inner wall of the left minor side of the mold and the right discharge ports are opposed to the inner wall of the right minor side of the mold. The area of the openings of the lower discharge ports is smaller than the area of the openings of the upper discharge ports. The ratio of the area of the openings of the lower discharge ports to the area of a sum of the areas of the openings of the upper and lower discharge ports is not less than 0.2 but not more than 0.4.