Tundish lining construction and refractory material composition

Source: | Author:ChangXing Refractory | Published time: 1138 days ago | 723 Views | Share:

The tundish is a transition device for molten steel between the ladle and the mold.

The main tasks of the intermediate package are:

(1) Diversion of molten steel. For the multi-stream continuous casting machine, the molten steel is distributed to each mold through the tundish;
(2) Steady flow. Reduce the static pressure of the molten steel, maintain a stable liquid level in the tundish, and smoothly inject the molten steel into the mold;
(3) Store molten steel. When replacing the ladle with multiple furnace continuous casting, the drawing speed is not reduced, creating conditions for multiple furnace continuous casting;
(4) Purify molten steel. In a long pouring time, the temperature of the molten steel is basically unchanged, and the inclusions in the molten steel are further raised to prevent the molten steel from contacting air and avoid oxygen and nitrogen absorption.

The tundish is lined with refractory materials, and generally includes the following parts:

(1) Insulation layer (10~30mm), this layer is next to the steel shell of the tundish, usually using asbestos board, insulation brick or lightweight castable. The best effect is aluminum silicate fiber felt, which has low thermal conductivity and is easy to build.
(2) Permanent layer (100 ~ 200mm), this layer is in contact with the insulation layer, and its material is generally clay brick. The overall permanent lining is the most common, and the castable is generally high-alumina or mullite self-flowing castable.
(3) Working layer (20-50mm), which is in contact with molten steel and is the key part. Nowadays, insulation boards or coatings are commonly used. Insulation panels are generally siliceous, magnesia, and forsterite; Coatings are magnesia, magnesia chromium, and magnesia calcium. The paint is sprayed mechanically or applied manually.
(4) Tundish well block is inlaid at the bottom of the tundish and used to install the tundish nozzle. The material is usually high aluminum.
(5) The material of the bottom of the package is basically the same as that of the working layer. The working layer of the tundish bottom is easily damaged by the impact of molten steel and requires corrosion resistance and wear resistance. Generally, high alumina bricks or dense high alumina bricks and aluminum chrome bricks are used. Special large high-strength tar magnesia bricks are also used. The impact part of molten steel is reinforced by stony bricks or prefabricated blocks.
(6) The cover is covered on the tundish, which can play the role of heat preservation and splashing of molten steel. The material is made of clay or high-aluminum castable.
(7) Slag retaining wall (weir), which is built in the tundish and can be a single wall or a double wall. The material of the slag retaining wall weir is usually high-alumina bricks, but can also be made into prefabricated blocks, and its purpose is to block. In order to improve the cleanliness of molten steel, a molten steel filter can be installed on the slag retaining wall.
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