Analysis of Characteristics of Refined Ladle Dispersion Type Breathable Bricks

Analysis of Characteristics of Refined Ladle Dispersion Type Breathable Bricks

Due to the special structure of the dispersion block, the dispersion-type air-permeable brick avoids the problem of the slit steel of the slit-type air-permeable brick, and can ensure the air permeability; at the same time, the bubbles are small, many and uniform, and the bottom blowing and stirring effect is good. It is because of these properties , so that the dispersion type ventilation brick has been widely used. Today, Xiaobian will give you a detailed introduction to the performance of a new type of dispersion type ventilation brick for refining ladle.

1, the internal structure

Dispersion type ventilation bricks need to make the bottom round table and dispersion block first, and then form the brick core like ordinary slit type ventilation bricks, and the production process is more complicated.

2, physical and chemical indicators

In order to ensure the long life of the dispersion block, the dispersion type breathable brick adopts synthetic raw materials with high strength, high refractoriness and excellent corrosion resistance, and adopts a combination structure of a breathable inner core and dense high-strength materials.

3, Microstructure

The microstructure of the breathable inner core and the simulated phenomenon of blowing water are shown in Figure 2:

Because of its microstructure characteristics, the new type of diffused permeable brick will not cause the bottom blowing impermeability or bad phenomenon caused by the slit steel that often occurs in the original slit type permeable brick. The flow in the slit produces a large temperature gradient, and the local thermal stress is concentrated near the slit, especially at the gas outlet of the slit, which causes the size of the slit to change during use, resulting in the molten steel easily entering the slit. In the middle, it will cause the bottom blowing impermeability or bad phenomenon. In addition, if the bottom blowing valve is quickly closed at the end of refining, the molten steel will enter the slit with positive pressure, so it is necessary to install a reverse osmosis one-way stop valve on the argon blowing pipeline. Therefore, the slit type ventilation Bricks must have suitable and stable slit airway size and raw materials with good thermal stability to reduce slit steel. The ventilation channels of diffused ventilation bricks are a large number of connected pores dispersed inside the brick body (as shown in Figure 2). ), these micron-scale curved channels cause a large resistance to the penetration of molten steel, which is basically non-permeable in actual use. As shown in Figure 3, the air bubbles generated by the diffused permeable brick are small, uniform and dense, making it easier to Stir the molten steel to a uniform temperature, it is easier to cause the inclusions to float up and achieve a better refining effect.

4, thermal stability

The new type of diffused permeable brick is not easy to cross the surface of the brick core. When the ordinary slit type permeable brick is blown with argon, the outlet of the slit is in direct contact with the high-temperature molten steel and the cold air flows out continuously, resulting in a large temperature gradient, resulting in slits The thermal stress at the air outlet is particularly large, coupled with the rapid cooling and rapid heating during use, it is easy to cross the air outlet near the slit, causing the slit to shift and the bottom to blow through. Thermal stress can easily cause the cross-section of the slit-type permeable brick, which puts forward relatively high requirements for the thermal shock resistance of the refractory material. However, there are micron-scale gas channels on the entire working surface of the diffused permeable brick, and the working surface temperature The gradient is small, so the new type of diffused breathable brick is not easy to cross the surface of the brick core.