Factors influencing the effect of argon blowing at the bottom of ladle

The quality of the use of argon-blown air-permeable bricks at the bottom of the ladle is very important to steel manufacturers, and unfavorable factors should be avoided or dealt with as much as possible during use. The main factors affecting the effect of argon-blowing ventilating bricks at the bottom of ladle are as follows:

1. Permeable brick working surface seepage steel

The working conditions of the breathable bricks are very harsh. The static pressure of the molten steel in the large ladle is large, and the required stirring strength is also large. Therefore, the key to ensuring the ventilation rate is that the breathable bricks have strong anti-seepage steel ability. In the production practice of steel manufacturers, the working surface of ventilating bricks often forms steel, so it is necessary to clean the working surface with an oxygen lance. If the slit-type ventilating brick is not cleaned, it will easily occur that the ventilating brick is not ventilated.

2. Breathable brick (slit type) is blocked by molten slag

After the ladle is continuously cast, the working surface of the ventilating brick is fully in contact with the slag, and the slag will continuously infiltrate the interior of the ventilating brick. As the temperature of the ladle decreases, the viscosity of the steel slag continues to increase, and the slit passage of the ventilating brick is likely to be blocked. As a result, the amount of air blown at the bottom of the ladle is small or airtight.

3. Material changes

Breathable bricks are multi-element and multi-phase composite materials with structural features such as particles, mechanical properties, interfaces, and pores. The main chemical composition of the air-permeable brick is alumina, followed by a certain amount of magnesium oxide. Due to the different chemical composition, the density, compressive strength, and flexural strength of the air-permeable brick will be different.

4. Air source pressure fluctuation

In the actual use of the ventilating brick, the argon gas supply pressure will fluctuate due to many reasons. When the argon gas pressure is too low, the molten steel cannot be blown and the bottom blowing fails; when the argon gas pressure is too high, the molten steel will easily turn up severely. After contact with air, the molten steel will be oxidized again.

5. Long package suspension time

When the ladle is stopped for too long, the baking time is insufficient or not baking, the temperature of the inner lining of the ladle is not enough. After the steel is connected, the temperature of the molten steel at the bottom of the ladle is low, and the cold steel is attached to the bottom of the ladle, which hinders the blowing of the ventilating brick at the bottom, resulting in ventilation failure.