Precautions for the operation of LF furnace refining technology

Precautions for the operation of LF furnace refining technology

1. Inspection and preparation before refining of power distribution workers

1.1 Carefully check whether the selector switches are correct according to the equipment operating regulations.

1.2 Whether the high-voltage electrical system is normal. If there is any abnormality, report to the dispatching room and notify the electrical personnel to deal with it in time.

1.3 After the inspection is correct, report the refining furnace head.

2. Inspection and preparation of refining workers before refining

2.1 Confirm that the temperature measurement, oxygen determination, and sampling devices are working properly, and the number of temperature measurement heads, oxygen determination heads, and samplers are sufficient.

2.2 Check whether the slag material, alloy material, deoxidizer, recarburizer, etc. are sufficient, and confirm the alloy composition.

2.3 Confirm that the furnace cover is up and down normally, and there is no water leakage in the furnace cover water cooling system, conductive copper arm, electrode clamp, etc.

2.4 Check whether the refractory material of the furnace cover can continue to be used, especially whether the refractory material around the electrode hole can continue to be used.

2.5 Confirm that the wire feeding machine is working properly, the number of various threads is sufficient, the composition is clear, and the installation is in place.

2.6 Check for air leakage in the bottom blowing pipe network, and the main pipe pressure is above 1.5MPa.

2.7 Confirm that the ladle car is running normally, the parking position is accurate, and there are no obstacles in the track. 2.9 The platform is ready with a large package of heat preservation agent.

3. Packing station

3.1 After the ladle is hoisted to the refining station, a special person will direct the handlebar to seat the ladle steadily. Check whether the rack is deformed, and check whether the wall of the bag is red.

3.2 Check the upper edge of the ladle for residual steel, residue, foreign matter, etc., to prevent the ladle from being super high, and to ensure that the ladle is in smooth contact with the furnace cover.

3.3 Connect the argon blowing pipe and adjust the argon blowing flow.

4. Adding slag material station

4.1 After the refining ladle truck runs to the slag loading station and stops, check whether the station is accurate.

4.2 Add slag-making materials to the ladle, the ratio of slag to material is lime:fluorite=3:1～5:1, adjust the ratio according to the slag condition, and the amount of slag material added is 4～7kg/t steel.

5. Put the ladle on the upper ladle station, turn on the bottom blowing Ar gas, and blow and stir. Common flow rate for Ar blowing: 130-150NL/min, pressure: 0.2-0.4MPa.

6. The refining ladle is placed at the upper ladle station, and samples are taken at a suitable location for full analysis and temperature measurement.

7. Start the seat charter to make the refining bag enter the heating station, and lower the heating cover.

8. Adjust the input voltage and current according to the measured temperature and the requirements of the steel type, and lower the three-phase electrode for energization and heating.

9. When the power is off, the three-phase electrode is raised, the furnace cover is raised, and the temperature is measured. The temperature and composition of the molten steel are required to be qualified.

13. During the refining process, in principle, high-pressure blowing Ar refining is prohibited. If high-pressure stirring is required due to abnormal conditions, the time should not exceed 2 minutes.

14. After adding slag and alloy, 15 minutes refining time must be guaranteed.

15. White slag tapping, guarantee (FeO+MnO)≤1.0%

16. Refining should control the temperature of molten steel on the stage according to the production rhythm and ladle conditions to ensure that the superheat of the tundish is 20~35℃.

17. The temperature and composition before feeding the silk must meet the requirements.