Emergency Handling of Unexpected Situation in Smelting of Intermediate Frequency Electric Furnace
1. Power outage accident treatment-emergency treatment of cooling water
(1) The dual power switch in the main power distribution cabinet of the electric furnace control room should be kept at the self-switching position. When the main power supply fails, the security power supply will automatically cut in, and then immediately restart the furnace water pump;
(2) When the main power supply and the security power supply are cut off at the same time, the electrician on duty must be notified immediately, and the emergency generator must be started to ensure that the small water pump of the furnace body is powered and the furnace body cooling water is run. Therefore, diesel generators must be guaranteed to have a certain amount of diesel oil, and run together with the equipment once a month;
(3) When the diesel generator fails to start, immediately cut the tap water into the furnace body; (the specific water inlet and outlet arrangement and operation plan shall be implemented by the equipment department and reported to the safety department for record);
(4) Due to the power failure, the water supply of the coil is stopped, and the heat conducted from the molten iron is very large. If there is no water flow for a long time, the water in the coil may turn into steam, destroying the cooling of the coil, and the hose connected to the coil and the insulation of the coil will be burnt out.
2. Power outage accident handling-emergency treatment of molten iron in the furnace
(1) A power outage occurs during the period when the cold charge starts to melt. The charge has not been completely melted and does not need to be dumped. Keep it as it is, just continue to supply water, and wait for the next time the power is turned on to restart;
(2) Due to the failure of the intermediate frequency power supply, the molten iron has melted, but the amount of molten iron is small and cannot be poured (the temperature is not reached, the composition is unqualified, etc.), you can consider turning the furnace to a certain angle and then solidify naturally. If the quantity is large, consider dumping the molten iron;
(3) Due to the sudden power failure, the molten iron has already melted. Try to insert a pipe into the molten iron before the molten iron solidifies to facilitate the removal of gas during re-melting and prevent the gas from expanding and causing an explosion;
(4) When the solidified charge is energized and melted for the second time, it is best to tilt the furnace forward at a certain angle, so that the molten iron underneath can flow out part of the inclined lower part to prevent explosion.
Three, emergency treatment of molten iron
(1) Liquid iron leakage accidents are likely to cause equipment damage and even endanger people. Therefore, it is necessary to do the maintenance and maintenance of the furnace as much as possible to avoid liquid iron leakage accidents;
(2) When the alarm bell of the furnace lining thickness measurement device rings, the power supply should be cut off immediately, and the surroundings of the furnace body should be inspected to check whether the molten iron leaks out. If there is any leakage, dump the furnace immediately and pour out the molten iron;
(3) If the molten iron has been found, evacuate the personnel immediately and pour the molten iron directly into the pit in front of the furnace;
(4) The molten iron leakage is caused by the destruction of the furnace lining. The smaller the thickness of the furnace lining, the higher the electrical efficiency and the faster the melting speed. However, when the thickness of the furnace lining is less than 65mm after wear, the entire thickness of the furnace lining is almost always a hard sintered layer and a very thin transition layer. There is no loose layer, and small cracks will occur when the lining is slightly subjected to rapid cooling and heating. This crack can penetrate the entire interior of the furnace lining, making it easy for molten iron to leak out;
(5) When furnace leakage occurs, personal safety should be ensured first. When considering equipment safety, the equipment mainly considers the protection of induction coils. Therefore, if furnace leakage occurs, the power supply should be turned off immediately and the cooling water should be kept unblocked.
4. Emergency treatment of excessive cooling water temperature
(1) The sensor cooling water pipe is blocked by foreign matter, which causes the water flow to decrease and the cooling water temperature is too high. At this time, it is necessary to cut off the power first, and then use compressed air to purge the water pipe to remove foreign objects. It is best not to stop the pump for more than 8 minutes;
(2) The coil cooling water channel has scale, which causes the water flow to decrease and the cooling water temperature is too high. According to the water quality of the cooling water, the obvious scale on the coil waterway must be pickled in advance every one to two years;
(3) The sensor water pipe suddenly leaks. This water leakage is mostly caused by the insulation breakdown between the inductor and the water-cooled yoke or the surrounding fixed support. When this accident is discovered, the power should be cut off immediately, the insulation treatment of the breakdown point should be strengthened, and the surface of the leaking point should be sealed with epoxy resin or other insulating glue to reduce the voltage for use. The hot metal in this furnace should be hydrated, and the furnace can be repaired after it is poured. If the coil channel is broken down in a large area, the gap cannot be temporarily sealed with epoxy resin, etc., so the furnace has to be shut down, molten iron is poured, and repaired.