1. Oxidation of furnace gas

From the converter to the molten iron to the blowing process, the tapping port is under the atmosphere of high temperature oxidation. The furnace gas produced in the blowing process contains a large amount of CO, and the CO reaction occurs when it is discharged from the tapping port. A decarburized layer is formed on the inner wall surface of the mouth, which directly causes damage to the steel tap.

2. Friction damage and mechanical erosion of molten steel and slag

When tapping, the tapping port is subjected to the huge pressure of the molten steel in the converter. At the same time, when the molten steel and slag flow out of the tapping port, friction and scouring occur with the inner wall of the tapping port, which directly causes mechanical damage to the inner wall of the tapping port.

3. High temperature melting of molten steel and slag

The tapping temperature is generally 1680~1710 °C. Under the action of high temperature molten steel, the material of the tapping port will soften, the strength will be significantly reduced, and even melted, causing damage to the taphole.