What are the different types of nozzle systems for steel ladles?

There are several types of nozzle systems for steel ladles:

Stopper nozzle:

Working principle: The raising and lowering of the stopper rod drives the stopper brick to open and close the nozzle, thereby adjusting the flow rate of the molten steel being poured.

Structural features: The stopper rod lifting mechanism usually has a stopper rod gap elimination device, which ensures that the center of the stopper rod and the center of the nozzle remain consistent after multiple uses, ensuring the normal opening and closing of the nozzle and accurate control of the molten steel flow rate.

Application scenarios: In the early days, it was more commonly used in some small foundries or occasions where the accuracy of molten steel flow control was not particularly high. However, with the development of continuous casting and ladle refining, due to the prolonged residence time of molten steel in the ladle and the increase in molten steel temperature, this type of nozzle has gradually been replaced by sliding nozzles, but it still has some applications in some specific small-scale production scenarios.

Sliding nozzle:

Working principle: The sliding mechanism is installed at the bottom of the steel ladle and consists of an upper nozzle, an upper slide plate, a lower nozzle, and a lower slide plate in the ladle bottom lining brick. By sliding the upper and lower slide plates, the upper and lower nozzles are opened or closed to adjust the outflow of molten steel.

Structural features: Installation and maintenance are carried out outside the steel ladle, which greatly improves working conditions and also speeds up the turnover rate of the steel ladle.

Application scenarios: This is the commonly used nozzle type in large foundries and steel plants, especially suitable for continuous casting and ladle refining processes, and can meet the requirements of precise control of molten steel flow rate and rapid turnover of steel ladles.

Quick-change nozzle:

Working principle: During continuous casting, when it is necessary to quickly replace the nozzle to meet the requirements of continuous casting, the quick-change nozzle can quickly disassemble and install new nozzle components. It usually uses a special connecting mechanism and sealing method to complete the nozzle replacement in a short time, reducing the interruption of casting.

Structural features: It has the characteristics of quick connection and reliable sealing. It is generally equipped with special locking devices and sealing elements to ensure that molten steel does not leak during replacement, and that the newly replaced nozzle can be quickly put into use to ensure the normal casting of molten steel.

Application scenarios: It is mainly used in occasions with high requirements for casting continuity, such as slab and wide and thick slab continuous casting, which can effectively improve production efficiency and reduce production interruptions and molten steel loss caused by nozzle replacement.

In addition, in the continuous casting process, there are also long nozzles and submerged nozzles related to the steel ladle nozzle system. The long nozzle is installed at the end of the lower nozzle of the steel ladle sliding nozzle, used to protect the steel flow when the molten steel is poured from the steel ladle into the intermediate vessel, preventing the molten steel from directly contacting the air and causing secondary oxidation. The submerged nozzle is installed at the bottom of the intermediate vessel and inserted below the molten steel surface of the crystallizer. Its main function is to prevent secondary oxidation and splashing of the molten steel flow in the intermediate vessel, avoid the crystallizer protective slag from entering the molten steel, and improve the flow state and heat flow distribution of the molten steel flow in the crystallizer.