Ladle nozzles (ladle slide gates) can be divided into various types according to their structure, function and application scenarios.
1. Classification By Structure And Working Principle
(1) Slide Gate Nozzle
Composition: It consists of an upper and lower slide plate (refractory material) and a driving mechanism (hydraulic/mechanical). The flow rate of molten steel is adjusted or cut off by the relative sliding of the slide plates.
Features:
Single slide plate: controlled by a single slide plate, simple structure, used for ordinary steel grades.
Double slide plate: two pairs of slide plates are superimposed for better sealing, suitable for high-oxygen steel or high-alloy steel.
Application: the mainstream flow control method for continuous casting and die casting.
(2) Rotary Nozzle
Principle: the flow of molten steel is adjusted by rotating a refractory brick with holes (rotor).
Features:
Even wear, long life, but complex structure and high maintenance costs.
Application: Some small and medium-sized ladles or special steel types.
(3) Stopper Rod System
Principle: The opening and closing of the nozzle is controlled by lifting and lowering a stopper rod made of refractory material.
Characteristics:
High adjustment accuracy, but the stopper rod is easily eroded by molten steel and is mostly used for tundish flow control.
Application: Traditional die casting or billet casting.
2. Classified By Function
(1) Ordinary Nozzle
Material: aluminum-carbon, high-aluminum
Function: basic flow control, suitable for general steel grades
(2) Long Nozzle (Long-Necked Nozzle)
Features: extends below the level of the tundish liquid surface to prevent splashing and suction of molten steel.
Application: continuous casting protection pouring.
(3) Submerged Entry Nozzle (SEN, Submerged Entry Nozzle)
Characteristics: Inserted into the molten steel in the tundish or mold to completely isolate the air.
Types:
Straight-through type: simple pouring.
Multi-hole type (side hole/bottom hole): optimizes the molten steel flow field and reduces slag entrainment.
Application: slab and billet continuous casting.
(4) Gas-Purged Nozzle
Features: Argon and other inert gases are introduced to prevent nozzle blockage (e.g., Al₂O₃ deposition) and steel oxidation.
Application: high-oxygen-sensitive steel grades (e.g. aluminum-tempered steel).
(5) Anti-Clogging Nozzle
Design: The inner wall is coated with materials such as CaO-ZrO₂, or a special structure (such as a slit-type channel) is used.
Application: high-aluminum steel, silicon steel and other steel grades that are prone to oxidation.
