Operation procedure:
Preparation:
1) Check the condition of furnace body: check whether the furnace lining, copper tube induction coil, cooling water pipe and furnace body rotating mechanism are normal. If the furnace lining needs to be repaired, repair it first.
2) Check whether the power supply and electrical control system are normal.
3) Prepare tools and temperature measuring instruments (guns), etc.
4) Start the cooling water system and check the water pressure. The cooling water pressure of copper tube induction ring shall not be less than 0.2MPa.
Turn on the cooling water switch of the power control box and the cooling water switch of the furnace.
Charging: the charging must be clean and free of rust, oil stain, sundries, etc. the charging shall not exceed the height of the induction ring, the long charging shall be vertically loaded into the furnace, and efforts shall be made to “loosen up and tighten down”.
Melting:
1) Start up: turn on the main power switch, check whether the capacitor is locked, whether the power control knob is at zero position, turn on the “on” button of the frequency regulator for about 10 seconds, the frequency reaches 1500 Hz, turn the button clockwise, slowly increase the frequency and power until the limit indicator light is on.
2) Maintain the power limit. As the charge melts, the unfilled charge will be added in the melting process one after another. The charge shall be poked in time to prevent “bridging”.
3) When the rated power is reached and all furnace materials are melted, check that the drainage temperature of cooling water should be lower than 30 ℃, and pay attention to covering the liquid steel level.
Deoxidizing and adjusting composition: when the furnace charge is cleaned, sample and analyze the composition, and adjust the composition according to the analysis results. Whether deoxidizing or adding the alloy adjusting composition first depends on the type of alloy added. After the furnace charge is cleaned and heated, deoxidization can be carried out. Manganese is added first, then monocrystalline silicon is added, or composite Deoxidizer is added at one time.
Tapping and pouring: power off and stand still, use slag making agent to remove steel slag, clean (air blowing) furnace surface and tapping port, tapping and pouring.
Boiler shutdown: turn the power control knob to “zero” position, turn off the frequency regulator for two minutes, and then cut off the power supply, reduce the cooling water pressure, delay the cooling time of the furnace body, and avoid cracks in the furnace lining.
Turn on the timing switch of the cooling water system of the furnace body, and cool for at least 6 hours after shutdown.
Precautions:
The order of adding alloy for adjusting composition shall be reasonable, and the temperature adjustment shall be paid attention to.
1) Some refractory and high density elements should be added first, while alloy elements with high affinity to oxygen can only be added under the condition of good deoxidation, and the temperature should not be too high when adding, so as to reduce the burning loss.
2) The heating time must be determined according to the amount of alloying elements added.
Deoxidize strictly.
5-7 times of slag removal in the whole smelting process.
The water-cooled die head must be barbecued before returning to the furnace.
the alloy should be preheated before adding, and the adding amount should be strict.
Carry out operation and maintenance in strict accordance with equipment operation and maintenance requirements.
During smelting process, pay attention to check the condition of furnace to prevent furnace penetration.