The sliding nozzle is a control device of molten steel in the casting process of the continuous casting machine, which can accurately adjust the water flow from the ladle to the continuous casting tundish, so that the inflow and outflow of molten steel are balanced, so that the continuous casting operation is easier to control, and the indispensable part of the smelting is generally composed of the drive device, the mechanical part and the refractory part (that is, the upper and lower slide plate, the lower nozzle) .