An Introduction To Tundishes
Modern metal production simply wouldn’t work without tundishes, where production would be inefficient and more costly. Through the use of refractory-lined tundishes, the process of metal casting is greatly enhanced. The core components of tundish linings such as chromite and anthracite are available from African Pegmatite - the preferred industrial provider for a wealth of refractories and minerals for the foundry industry. A tundish is a device used in the casting of metals. It is any open-topped vessel with holes in the bottom to deliver molten metal at a controlled rate into casting moulds. It is often used between smelting and casting to ensure a consistent and regulated flow, whilst enabling the switchover of casting moulds if needed. Tundishes are often made of steel and are lined with some kind of liner, which is always a refractory material, often in brick form. Such refractory materials employed as tundish linings, or of components in tundish linings, include anthracite, chromite and glass powders amongst others. Some 7% of all refractory materials in Europe are used for tundishes and in continuous casting(1,2), with a respectable 5% of this going to landfill after use(3). Tundishes are closely related to ladles, which are used to transport molten metal from the furnace to the tundish ahead of casting. These large, refractory lined buckets are operationally very similar to tundishes and thus the principles for tundish lining design and materials largely apply to ladles as well. Overall, it can be said that an ideal tundish lining will have the following qualities:
Ability to withstand temperatures in excess of 1,500 °C
Maintenance of its shape at high temperatures
Resistance to attack by slag
Have no chemical or physical interaction with the molten metal
Advantages of Tundish Nozzle
Tundish nozzles are basically used for controlling the flow of steel from the Tundish to the Continuous Casting equipment. Different kind of tundish nozzles include, Alumina, Alumina Carbon, Zirconia Alumina Nozzles, which are manufactured for single to multiple casting application. The tundish is a refractory container, and the molten steel poured from the ladle is distributed to each mold through the tundish metering nozzle.The quality and life of the tundish nozzle directly affect the purity of steel before entering into mold. Tundish nozzle is divided into two types: argon blowing and non-argon blowing. The tundish nozzle is embedded in the seat brick at the bottom of the tundish and used in conjunction with the stopper. The tundish nozzle is mainly used to adjust the flow of molten steel entering the mold, and argon can be blown through the inner wall to prevent the nozzle from being blocked. The material of the tundish nozzle is selected according to the steel type to be poured. When casting general carbon steel, a mullite nozzle containing 70~75% Al2O3 can be used. Magnesium oxide or zirconium oxide nozzles can be used when pouring free-cutting steel. When casting high-manganese steel, high-aluminum graphite or zirconia nozzles can be used. Depending on the type of cast steel, there are magnesia, zirconia, and high-aluminum graphite or zirconia. It is one of the important smelting methods to blow inert gas into molten steel through the tundish nozzle. Therefore, tundish nozzle is widely used.
1. Sliding quickly, accurately, without bias, leaking steel
2. Good corrosion resistance, no obvious diameter expansion, long service life, no bias flow, scattered flow phenomenon;
3. Good thermal shock performance
4. Strong anti-erosion performance
Tundish nozzle is an important component of continuous casting. Through the tundish nozzle, the molten steel flows from the tundish into the crystallizer. During this process, the outlet aperture will be eroded and widened, the amount of molten steel per unit of time increases and the surface of molten steel in the crystallizer rises, which requires increasing casting speed to digest the excess molten steel.
