Sliding nozzle is a control device of the molten steel in the casting process of casters. It can precisely adjust the molten steel flow rate from the ladle to the continuous casting tundish. It is an indispensable part of smelting. 

The sliding nozzle pocket block has similar properties to the ladle pocket block. In order to avoid the solidification of molten steel in the upper nozzle, the upper mouth of the sliding nozzle pocket block is bigger and deeper than the ladle pocket block. 

 

The upper nozzle block is directly installed in the pocket block and cannot be changed like the sliding plate, so it should have a longer service life than the sliding plate and synchronized with the pocket block. It is usually made of high corrosion resistance corundum materials or basic refractory materials. In order to solve the clogging problem in the upper nozzle when casting molten steel containing Al or Ti, in addition to improving materials, blow inert gas into the molten steel. The gas can stir the molten steel, form a gaseous film on the inner nozzle wall and prevent the deposited oxides in the molten steel from adhering to the nozzle wall and clogging the nozzle. 

 

Slide gate brick is the key component in the sliding nozzle. Its service life is closely related to its material. 

 

The down nozzle block is connected to the lower slide gate and moves with it. The lower nozzle block can rectify the flow of molten steel by the throttling operation of the slide gate and control the casting speed by adjusting the aperture of the down nozzle block. It is subjected to the corrosion of rapid heating, wear and slags. 

 

A ventilation plug is installed on the slide gate in order to avoid the solidification of molten steel and the clogging of the nozzle when casting. 

 

In addition to installing a ventilation plug, granular refractory materials are used as filler in the upper nozzle to avoid the solidification of molten steel and the successful casting.