Medium frequency furnace safety melting needs
What should be paid attention to in order to ensure safety during the smelting process of the intermediate frequency furnace?
(1) On-site personnel shall wear labor protection articles in strict accordance with the company's requirements, and use special filters when observing high temperature metals.
(2) The furnace lining should be checked frequently at regular intervals to prevent “depletion”. Check the furnace lining after cooling: The thickness of the lining (excluding the asbestos board) must be repaired when the burning loss is less than 65mm~80mm. If there is no abnormality, forcefully remove it around 250 furnaces. The feeding should be carefully and carefully avoided to avoid the “cross-bridge” and “capping” of the material. The ultra-high temperature of the metal under the "bridge, cover" will cause the lining corrosion to accelerate.
(3) The charge should be dry, free of flammable materials, closed containers, and not excessive rust. The violent boiling of liquid or flammable materials in the charge can cause the molten metal to overflow or even explode.
(4) There shall be no water in the pit before the furnace to prevent the molten iron from splashing and exploding after pouring.
2. Intermediate frequency furnace feeding method
(1) Regardless of the charge, the next melt should be slowly injected before the previous charge is melted. If the rust and sand-filled charge are used incorrectly, the block size and shape are poor, the charge is not tightly packed and the stretch is severe, or if the cold charge is too much, the “bridge” is likely to occur. The liquid level must be checked frequently. Once the bridge occurs, it should be disposed of immediately, and the “bridge” should be removed to avoid the “bridge” formation. Otherwise, the lower iron will overheat, causing erosion of the lower lining, or even leakage of iron or explosion.
(2) Bridge treatment method: reduce the melting current to below 500A; use iron rod to smash and wear; if not treated, tilt the electric furnace properly, keep the low power melting until the molten iron breaks through the bridge or the capping layer;
(3) After the furnace material is completely melted, the slag should be slag immediately to prevent the formation of a "slag cover". If it is formed into a "slag cover", it should be immediately powered off, and the "slag cover" should be broken and thrown out of the furnace, otherwise the lower iron will overheat, causing erosion of the lower furnace lining, or even leakage of molten iron or explosion.
Emergency treatment of intermediate frequency furnace smelting
1, power outage
(1) Emergency treatment of cooling water
1) The dual power switch in the distribution cabinet of the electric furnace control room should be kept in the self-switching position. When the main power supply is cut off, the security power supply will automatically cut in, and then immediately start the furnace water pump again;
2) When the main power supply and the security power supply are powered off at the same time, the duty electrician will be notified immediately, and the emergency generator will be started to ensure that the small water pump of the furnace body runs the furnace cooling water. Therefore, the diesel generator must ensure that it has a certain amount of diesel, and it runs once a month with the equipment;
3) When the diesel generator can not be started, the tap water is cut into the furnace body immediately;
4) Due to power failure, the water supply to the coil stops, and the heat conducted from the molten iron is very large. If water is not supplied for a long time, the water in the coil may become steam, destroying the coil cooling, and the insulation of the hose and the coil connected to the coil are burned out.
(2) Emergency treatment of molten iron in the furnace
1) When the cold charge starts to melt, a power failure occurs. The charge has not completely melted, it is not necessary to tilt the furnace, and the original state is maintained. Only the water is continuously passed, waiting for the next power supply to re-melt;
2) Due to the failure of the intermediate frequency power supply, the molten iron has melted, but the amount of molten iron is not much and cannot be poured (the temperature is not reached, the components are not qualified, etc.), and it is considered that the furnace is naturally solidified after being tilted to a certain angle. If the amount is large, consider dumping molten iron;
3) Due to sudden power failure, the molten iron has melted, trying to insert a pipe in the molten iron before the molten iron solidifies, so as to eliminate the gas when it is melted again, and prevent the gas from expanding and causing an explosion accident;
4) When the solidified charge is melted for the second time, it is better to tilt the furnace forward by a point angle, so that the molten iron under the bottom is allowed to flow out at a low inclination to prevent explosion.
2, the intermediate frequency furnace leaks molten iron
Leakage accidents can easily cause equipment damage and even endanger people. Therefore, it is necessary to do the maintenance and maintenance of the stove as much as possible to avoid leakage accidents.
(1) When the alarm of the furnace lining thickness measuring device is ringing, the power should be cut off immediately, and the surrounding of the furnace body should be inspected to check whether the molten iron leaks. If there is a leak, immediately tilt the furnace and pour the molten iron.
(2) If the molten iron has been found, immediately evacuate the personnel and directly pour the molten iron into the pit before the furnace;
(3) The leakage liquid is caused by the damage of the furnace lining. The smaller the thickness of the lining, the higher the electrical efficiency and the faster the melting rate. However, when the thickness of the lining is less than 65 mm, the thickness of the entire lining is almost a hard sintered layer and a very thin transition layer. Without a loose layer, the lining is slightly quenched and quenched to produce fine cracks. This crack can crack the entire interior of the lining, and it is easy to cause the molten iron to leak out.
(4) In the event of a leaking furnace, personnel safety should be ensured first. In consideration of equipment safety, equipment is mainly considered to protect the induction coil. Therefore, if a leak occurs, the power should be turned off immediately to keep the cooling water flowing.
3, the cooling water temperature is too high
(1) The sensor cooling water pipe is blocked by foreign matter, causing the flow of water to decrease and the temperature of the cooling water to be too high. At this time, it is necessary to first power off, and then use compressed air to purge the water pipe to remove foreign matter. It is best not to exceed 8 minutes for pump shutdown time.
(2) The coil cooling water channel has scale, which causes the water flow to decrease and the cooling water temperature to be too high. According to the quality of the cooling water, the obvious scale on the coil water channel must be pickled in advance every other year to two years.
(3) The sensor water pipe suddenly leaks. This leakage is mostly caused by insulation breakdown between the inductor and the water-cooled yoke or the surrounding fixed bracket. When this accident is discovered, it should immediately stop power, strengthen the insulation treatment at the breakdown, and seal the surface of the leak with epoxy resin or other insulating glue to reduce the voltage. The furnace is hydrated, and the furnace is repaired after the completion. If the coil water channel is broken down in a large area, it is impossible to temporarily seal the gap with epoxy resin, etc., and it is only necessary to stop the furnace, complete the molten iron, and repair it.
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