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　　Next, I’ll explain several key points about medium-frequency induction furnaces.

　　During the cold start-up of an intermediate-frequency induction furnace, before any molten metal comes into contact with the furnace lining, sufficient time must be allowed for the lining material to expand reversibly and seal any cracks caused by thermal shock. During cold start-up, a thermocouple with a sensitivity of 3–4 K should be used to monitor the temperature; the thermocouple should be positioned near the furnace wall or furnace bottom. For intermediate-frequency furnaces, the temperature measured by the thermocouple located in the middle of the effective coil serves as the control temperature. Additionally, installing gas burners at the bottom of the furnace can help reduce the temperature difference between the upper part of the furnace and the entire furnace lining.

　　For example, 5 tons. Medium-frequency electric furnace Cold-start time: Within 2 hours, heat the solid materials inside the furnace to 1100°C (heating rate: no more than 150°C/h for furnaces with a capacity of 4 to 15 tons, and no more than 100°C/h for 15-ton furnaces). Maintain the temperature at 1100°C for 3 hours. After holding the temperature, rapidly melt the charge material and bring the furnace into normal operation. Begin by supplying power at a low level, gradually increasing the power output (to 20% to 30% of full power within 15 minutes) in order to bridge any minor cracks that may have formed during cooling of the furnace lining.

　　To make better use of medium-frequency induction furnaces at work, it is necessary:

　　(1) Use a temperature gun to monitor the temperatures of thyristors, resistor-capacitor protection resistors, and the operating temperature of the medium-frequency induction furnace’s equalizing resistors. The temperature measurement is conducted in three stages: The first measurement takes about 5–10 minutes and should be performed when the power is turned on for approximately one-third of the time during the smelting of a batch of molten steel. The second measurement is taken around the time when the furnace is nearly full of molten steel. The third measurement is taken at the end of the smelting process—when the furnace is fully charged with molten steel today. Of course, to promptly detect and address any issues, it is essential to record the temperature readings from all three measurement stages.

　　(2) Check daily Medium-frequency electric furnace Are the cable screws loose?

　　(3) Before starting up each day, ensure that the power pump and furnace water pump of the medium-frequency induction furnace are turned on. The water pressure inside the power cabinet should be 1.5–1.7 kg, and the water pressure inside the furnace should be 1.5–2 kg.

　　(4) Keep the area around the boiler water pipes clean and free of iron filings and metal objects.

　　 Medium-frequency electric furnace Ten minutes before starting the equipment, turn on the water pump in advance and carefully observe whether there are any leaks or seepages. If any are detected, address them immediately to avoid disrupting production. If the machine detects an abnormal thyristor temperature, promptly investigate the cause—check whether a pipe has ruptured, resulting in insufficient water flow and inadequate heating, or whether the thyristor sleeve is blocked by debris. If you notice that the resistance in the rectifier’s RC protection circuit has a significantly different temperature compared to other resistors, immediately determine whether the capacitor is open-circuited or the resistor is damaged. Under normal circumstances, when the reactor starts up, you’ll hear a distinct buzzing sound and feel a slight tension.

　　That’s all for what our editor has explained. Does everyone understand now? We hope the editor’s explanation has been helpful to you all. Thank you for watching patiently, and we wish you all a happy life!

　　Our company specializes in steel-shell furnaces, series-connected electric furnaces, through-heating furnaces, medium-frequency furnaces, closed-water-cooling systems, casting electric furnaces, medium-frequency electric furnaces, and medium-frequency equipment. If you have any needs, feel free to contact us.