EBT’s tapping process and slag retention operation

Tapping process of Excentric bottom tapping electric arc furnace

When the temperature and composition of molten steel meet the tapping requirements, it can be ready for tapping. The tapping process is as follows:

1. Transport the ladle to the bottom of the tapping box of the electric furnace.

2. Before opening the tapping port, tilt the furnace to the side of the tapping port by about 3 ~ 5 °, so as to form sufficient static pressure of molten steel and prevent the slag from flowing into the ladle from the vortex generated by molten steel.

3. Open the tapping port support plate and start tapping. During tapping, the furnace is gradually tilted to about 12 ° to ensure that the molten steel depth above the tapping port is basically unchanged. When the molten steel reaches about 95%, the furnace body tilts back to the horizontal position at a faster speed (3 °/s) to avoid or reduce the flow of slag into the ladle from the tapping port and realize slag free tapping.

During the tapping process, there are two problems that should be paid attention to:

1. During the tapping tilting process of the furnace, don’t tilt too fast to prevent the molten steel in the tapping box from contacting the water-cooled cover plate on its upper part and causing burning loss;

2. Ensure that the molten steel in the tapping box has sufficient height to prevent the slag from being brought into the ladle due to the vortex effect.

Steel and slag retention operation of arc melting furnace

EBT electric furnace can retain 10% ~ 15% steel and more than 95% slag through eccentric bottom tapping. EBT electric furnace realizes slag free tapping by leaving 10% ~ 15% steel, maintaining sufficient molten steel in the tapping box and rapid back tilting (3 °/s) of the furnace body during tapping and tilting.

This operation of steel and slag retention can get rid of the traditional smelting process and provide good smelting conditions for realizing the modern steelmaking. Due to the operation of steel and slag retention, the arc is stable during smelting and melting period, and the formation of molten pool is advanced by 10 ~ 15 min, which can strengthen oxygen blowing in advance and improve the dephosphorization conditions of molten steel.

Notes when using the operation of steel and slag retention:

1. When changing the steel grade, whether the molten steel in the furnace has an impact on the composition of the steel grade shall be considered;

2. Lime shall not be added before charging;

3. The height of the charging basket shall be appropriate during charging to avoid being burned;

4. During smelting, pay attention to oxygen blowing and melting aid in advance;

5. Clean the slag and molten steel regularly and observe the erosion of the furnace bottom.