What are the reasons for the damage of ladle breathable bricks?

1, the effect of thermal stress

The refractory material on the working surface of the ladle breathable brick, especially the refractory material around the air outlet, is in direct contact with the high-temperature molten steel, and is affected by the high-temperature molten steel and the continuous outflow of cold air, resulting in a large temperature gradient. The quenching and heating effect of the breathable brick is large, especially near the air outlet, the thermal stress is greater, and cracks are prone to occur.

2, mechanical wear effect

In the process of tapping, the high speed of molten steel will scour the bottom of the steel tank, which will accelerate the damage of the ladle permeable brick; some people have studied the damage of the ladle permeable brick through the hydraulic model test and found that when the low-speed moving airflow is injected into the liquid phase melting When the gas flow rate is further increased, the reverse pulse frequency decreases, but the reverse impact strength further increases; in addition , When the argon blowing enters the normal eruption state, the intense bubbles form a gas eruption beam, the eruption beam strengthens the stirring at the bottom of the steel tank, the liquid phase movement at the bottom of the steel tank intensifies, and the 2-phase plume makes the ladle breathable bricks subjected to intense shearing and impact stress effect. Ladle breathable bricks are sheared by this plume when they are higher than the seat bricks, and the scouring is particularly significant. The part higher than the seat bricks is generally washed away after one use; Close the valve, the reverse impact of molten steel will also accelerate the damage of the ladle breathable brick.

3, chemical erosion effect

The working surface of the ladle breathable brick is in contact with the slag and molten steel for a long time.

4, the effect of mechanical stress

The working surface of the bottom refractory material is in direct contact with the high-temperature molten steel, and the temperature of the non-working surface of the bottom refractory material is relatively low. During the cycle of the ladle receiving molten steel → pouring molten steel → hot repairing ladle → receiving molten steel, the temperature of the ladle has been changing. , the volume of the bottom refractory material changes accordingly. Because of the existence of the temperature gradient of the bottom refractory material and the different expansion coefficients of the metamorphic layer of the bottom refractory material and the original layer, the corresponding volume of each layer from the working surface to the non-working surface of the bottom refractory material is different. The change is different, so that the force of shearing on the ladle permeable brick will cause transverse cracks in the ladle permeable brick, and even cause the ladle permeable brick to show a phenomenon of transverse fracture.