Intermediate Frequency Furnace Steelmaking Operation Regulations

1. Preparation before production.

1. When taking over, check first. Understand the use of furnace lining, whether the production tools are complete, and whether the furnace panel is exposed.

2. For every two furnace bases as a group, prepare ferrosilicon, medium manganese, synthetic slag, and heat preservation agent in place, and place them in the middle of the furnace.

3. Scrap steel must be prepared and the furnace must not be opened if there is a shortage of materials.

4. The insulating rubber bedding on the stove should be placed, and no gaps should be left.

2. Normal production

1. The new furnace lining shall be baked in strict accordance with the requirements of the new furnace baking process, and the baking time should be greater than 2 hours.

2. First add a small suction cup to the furnace to protect the furnace lining. It is not allowed to directly add bulk materials into the empty furnace, and then the furnace front worker should add the small materials scattered around the furnace into the furnace in time, and it is strictly forbidden to drop them. Under the stove, silicon steel sheets and punches are only allowed to be used in the oven, and they are not allowed to be used in the rest of the time.

3. The disk hoist lifts the material onto the stove from the stockyard, and the foreman sorts the scrap steel. The sorted inflammable and explosive materials are directly placed in the special receiving box and registered and confirmed by the stove security.

4. The flammable and explosive special inbox is placed between the two sets of furnace bases, and no one can move it at will.

5. The feeding in front of the furnace is mainly manual feeding. After the stove scrap is carefully sorted, the length of the material is less than 400mm, and the material that has been carefully selected by the furnace manager can be added by the suction cup. The driving commander is the small of each furnace seat. Furnace manager, if other people command the driving suction cup to feed, the driving operator is not allowed to feed.

6. The amount of suction cup feeding should be controlled. After adding, the scrap steel is not allowed to exceed the surface of the furnace mouth of the intermediate frequency furnace. The scrap scattered around the furnace mouth should be cleaned up with suction cups. During the feeding process, the area around the intermediate frequency furnace must be kept clean to prevent The falling of the scrap steel causes the induction coil or cable joint to ignite.

7. It is strictly forbidden to pile a large amount of scrap steel on the stage, and the total amount is controlled within 3 suction cups to reduce the difficulty of scrap sorting.

8. In the event of an explosion, the operator should immediately turn his back to the furnace mouth and leave the scene quickly.

9. During the pre-feeding process, for long materials, large blocks must be added upright into the furnace to melt into the molten pool as soon as possible. It is strictly forbidden to join in tiles to cause bridging. If the furnace material is found to be bridging, the bridge must be destroyed within 3 minutes, so that the furnace material can quickly melt into the molten pool. If the bridge cannot be destroyed in 3 minutes, the bridge must be destroyed by power failure or heat preservation before power is supplied Smelt normally.

10. For some scrap steel that is overweight and needs more than 2 people to move into the furnace, it is strictly forbidden to throw it into the furnace, and an excess should be made on the furnace edge, and then carefully pushed into the furnace.

11. When tubular scrap is added to the furnace, the top of the pipe should be in the direction of tapping steel, not in the direction of human operation.

12. For the cold steel and short-end continuous casting slabs in the slag ladle and tundish, the molten steel in the intermediate frequency furnace should be erected into the furnace after it reaches 2/3 or more, and it is not allowed to hit the furnace lining.

13. When the molten steel in the intermediate frequency furnace reaches more than 70%, take samples for analysis. The samples shall not have defects such as shrinkage holes, and no steel bars shall be inserted into the sample billets. After the chemical composition results of the samples are obtained, the personnel who prepares the elements shall determine according to the comprehensive situation of the two furnaces. The amount of alloy added.

14. If the chemical analysis in front of the furnace shows that the carbon is high, add some iron oxide nuggets for decarburization; if it shows that the carbon is low, add some pig iron nuggets for recarburization; if the average flow of the two furnaces is less than or equal to 0.055%, the raking is exhausted during tapping. Slag, increase the amount of synthetic slag added for desulfurization. At this time, the tapping temperature must be appropriately increased. If the average flow of the two furnaces is ≥0.055%, the molten steel should be treated in a separate furnace, that is, the molten steel with high sulfur content should be discharged into the ladle. Put it into other furnaces, then add some silicon steel sheet punches into the two furnaces for smelting, and then tap the steel. In case of high phosphorus, it can only be processed in separate furnaces.

15. After all the scrap steel in the furnace has been melted, the group in front of the furnace will carry out shaking slag dumping. After dumping the slag, it is strictly forbidden to add wet, oily, painted and tubular scraps into the furnace. Dry and clean materials should be used in the smelting process. Be ready. After the molten steel in the furnace is full, clean the slag at one time. After cleaning, quickly add the alloy to adjust the composition. The steel can be tapped more than 3 minutes after the alloy is added. The purpose is to make the alloy have a uniform composition in the furnace.

16. Tapping temperature: Upper continuous casting 1650—1690; molten iron around 1450.

17. Measure the temperature of the molten steel in front of the furnace, and control the power transmission curve according to the tapping temperature and tapping time required by continuous casting. It is strictly forbidden to keep the intermediate frequency furnace in the high temperature stage (the holding temperature is controlled below 1600°C).

18. After receiving the notice of continuous casting steel tapping, the temperature rises quickly. The temperature rise rate of the intermediate frequency furnace in the full furnace liquid state: about 20℃/min before 20 furnaces; about 30℃/min for 20-40 furnaces; and over 40 furnaces It is about 40°C/min. At the same time, note that the higher the temperature in the furnace, the faster the heating rate.

19. When the first furnace is tapped, 100 kg of synthetic slag is added to the ladle for heat preservation, and after the second furnace is tapped, 50 kg of covering agent is added to the ladle for heat preservation.

20. After the intermediate frequency furnace is finished, carefully check the lining of the furnace, and it is strictly forbidden to pour water into the furnace to cool down; if some parts of the furnace lining are severely corroded, the furnace should be repaired carefully before the furnace is turned on. The moisture in the furnace must be waited for Feeding can only be done after all evaporating dry. First add a suction cup silicon steel punch in the furnace, and then add other scrap steel. The first furnace after repairing the furnace should control the power supply curve, so that the furnace lining has a sintering process to ensure the repair of the furnace. As a result, it is strictly forbidden to add large pieces of waste to the furnace immediately after repairing the furnace.

21. During the whole production process, it is strictly forbidden to expose the furnace surface to the outside, and the insulating rubber should be replaced in time if it is damaged.