Induction melting furnace post operating procedures! Too practical
1. Inspection before starting the induction melting furnace
1.1 When entering the work site, labor protection equipment must be worn correctly.
1.2 Before starting the furnace, check the corrosion of the furnace lining, confirm that the furnace lining is in good condition and reliable, and then add materials to open the furnace for melting.
1.3 Before the furnace is operated, it must be ensured that there is no water or debris on the work site.
1.4 Before the furnace is running, start the cooling water pump to open the cooling water valves of each channel, check whether the cooling water channels are unblocked, whether there is any leakage, and whether the total inlet pipe pressure reaches the required value.
1.5 Check whether the driving is normal and the crane has no cracks to prevent accidents.
Second, the operation process
2.1 A part of raw materials (scrap iron and steel) is first added to the furnace.
2.2 The furnace changer switch is closed.
2.3 Close the main circuit switch of the frequency conversion device.
2.4 Power on the signal protection cabinet and the tilting control cabinet, and check whether the instruments and indicating signals are normal.
2.5 The induction melting furnace is powered by the inverter power supply, and the induction melting furnace increases the power. At the same time, observe the working conditions of the live induction melting furnace such as the inductor.
2.6 The feeding induction melting furnace should be operated by a dedicated person, and other personnel shall not use it casually. The electronic scale and scale must be checked before feeding, and the feeding induction melting furnace should be checked.
2.7 Strictly follow the batching list issued by the branch factory and add the materials in the specified order of addition.
2.8 Be especially careful when adding furnace materials to avoid damage to the furnace lining.
2.9 A smaller power (generally 40-60% of the total power) should be applied within the first ten minutes of power-on to prevent too much current fluctuation. After this period of time, the current tends to stabilize, and it can be melted with high power until the charge is completely melted.
2.10 In the melting process, the charge should be smashed frequently, and attention should be paid to avoid the phenomenon of "bridging" caused by the crowding of the charge. When most of the charge is melted, slag-making materials should be added. The slag covers the surface of the molten steel for easy removal.
2.11 Acid furnace non-oxidation steelmaking generally adopts the method of directly adding deoxidizer (ferromanganese, ferrosilicon) to molten steel for deoxidation (precipitation deoxidation method). Generally, 0.5% ferromanganese and ferrosilicon are added. It is better for the deoxidizer to sink into the molten steel in the form of a block.
2.12 The melting temperature is 1600℃ (under normal circumstances). According to specific process requirements at a specific time.
2.13 Final deoxidation must be carried out before tapping. If conditions permit, aluminum can be inserted in the furnace, or aluminum can be added to the ladle with a final deoxidation of 0.1%.
2.14 Before tapping, all slag in the furnace should be stripped off. After tapping, a heat-preserving slag agent should be added to the surface of the molten steel. The tapping temperature is generally 1600°C. The ladle must be fully baked to ensure that the inside of the ladle is clean and dry.
2.15 It should be noted that during the steelmaking process, all materials added to the furnace must be dry. Among them, the slagging material and the ferroalloy should be baked at a high temperature to prevent the gas from being brought into the molten steel.
2.16 When the charge is completely melted, samples can be taken for pre-furnace analysis.
2.17 There must be a proper margin for the volume of molten metal each time.
2.18 When the furnace is shut down, try to minimize the rapid cooling and heating of the furnace lining, so that the furnace lining cools down evenly and slowly.
2.19 Make a record of melting.
2.20 When spheroidization and inoculation are required, the inoculant and spheroidizing agent must comply with the "Standard for Casting Raw Materials", and the amount and specifications of the inoculant must be strictly in accordance with the process requirements. Generally, 75 ferrosilicon is about 0.5 to 0.3%. The grain size is 3～8mm and 5～12mm in front of the furnace. There are two kinds of 0.5～1.2mm and 1～3mm with the flow. During the spheroidizing treatment, the furnace temperature, the specifications of the spheroidizing agent, the amount of addition, the spheroidizing process, the type and the brand of the spheroidizing agent are strictly controlled according to the process requirements. The general addition amount varies depending on the casting wall thickness, structure, material, etc., and the approximate range is 1.0 to 1.8%. The processing temperature of molten iron is 1450～1500℃, and the addition amount of inoculation (following flow) is generally 0.4～0.7%. In the production of ductile iron in lost foam, in order to obtain a high pouring temperature (1380～1450℃), the spheroidizing temperature must first be increased, and high-temperature spheroidizing is prone to poor spheroidization. Strictly standardized operation and spheroidizing treatment The control of process details is the key to ensure the stability of spheroidization.
2.21 During the melting process, when the furnace is found to be faulty or the furnace is shut down, the inverter power adjustment knob of the induction melting furnace must be adjusted to return the power to zero before the main circuit switch and the main control power switch can be disconnected. It is strictly forbidden to suddenly disconnect the main circuit switch and the main control power switch without returning the power to the zero position.
2.22 During the melting process, the return water temperature of the circulating water distributor should be monitored at any time not to be higher than 35°C.
2.23 The furnace must be tilted back to reset after the steel and molten iron are released.
2.24 During the smelting process, the furnace shell has a certain amount of induction electricity, so workers in front of the furnace should wear insulating gloves, insulating shoes, step on insulating pads, and wear protective masks. It is strictly forbidden to operate with wet hands to ensure safety. produce.
2.25 After smelting, the molten iron and impurities in the furnace should be cleaned, and then the electric furnace is cut off, the induction coil reduces the water pressure to supply water, and when the furnace is completely cooled to room temperature, stop the circulating water and disconnect the power supply of the water pump.
2.26 Check the condition of the induction melting furnace at any time during work, and immediately shut down if abnormal conditions are found, and notify the relevant team for maintenance. (Need to go through the procedure of the defect notice of the induction melting furnace, you can work first, and then complete the procedure.)
2.27 In the event of a failure that cannot be recovered within 10 minutes, the emergency plan formulated by the company must be activated to ensure the safety of the induction melting furnace (large furnace, etc.) and prevent accidents.
2.28 After finishing the work, turn off the power supply of all induction melting furnaces.
2.29 Clean up the work site and keep the site tidy and hygienic.
3. Routine maintenance and repair of induction melting furnace
3.1. Regularly check whether the sealing of the water cooling pipe joints of the induction melting furnace is firm. When tap water or well water is used as the cooling water source of the induction heating induction melting furnace, it is easy to accumulate scale and affect the cooling effect. When plastic water pipes age and produce cracks, they should be replaced in time. When the intermediate frequency electric furnace device is running in summer, the use of tap water well water cooling is often prone to condensation, and the closed water circulation cooling system should be considered. The operation should be stopped when the condensation is severe.
3.2. Regularly check whether the load wiring of the induction melting furnace is good and whether the insulation is reliable. Clean the dust in the intermediate frequency power supply cabinet regularly, especially the outside of the thyristor die, which should be wiped clean with alcohol. The frequency conversion device in operation generally has a dedicated computer room, but the actual operating environment is not ideal. In the smelting and forging process, the dust is very large and the vibration is strong; in the induction melting furnace diathermic quenching process, the device is often close to the induction melting furnace such as pickling and phosphating. There are more corrosive gases, which will damage the components of the device. Function to reduce the insulation strength of the device. When there is a lot of dust, the surface discharge phenomenon of the component often occurs. Therefore, care must be taken to frequently clean the surface of the original dust to prevent malfunction.
3.3. Regularly inspect and repair the induction melting furnace device. Check and tighten the bolts and nuts crimping of each part of the induction heating induction melting furnace device. If the contacts of the contactor relay are loose or have poor contact, they should be repaired and replaced in time. Do not avoid strong use to prevent greater accidents.
3.4. Detect the rated voltage and current of the induction melting furnace. This kind of regular inspection can prevent the circuit from malfunctioning. It is necessary to take good care of the intermediate frequency electric furnace on a regular basis. This kind of maintenance is the key to increasing the service life of the intermediate frequency electric furnace and an important prerequisite for ensuring the personal safety of the operators. Since the entire working environment of the intermediate frequency electric furnace is carried out under a high temperature, high pressure and high current conditions, the room where the intermediate frequency electric furnace is placed must be cleaned and cleaned regularly.
Four, safety precautions:
4.1 Before the furnace is operated, it must be ensured that there is no accumulation of water and debris on the work site.
4.2 It is strictly forbidden to suddenly disconnect the main circuit switch of the electric furnace and the main control power switch without returning to the zero position.
4.3 During the steelmaking process, all materials added to the furnace must be dry. Among them, the slagging material and the ferroalloy should be baked at a high temperature to prevent the gas from being brought into the molten steel. Various metal charges are prepared according to the process requirements, and unqualified charges are not allowed to be used.
4.4 When pig iron, ferrosilicon, ferromanganese, scrap steel, etc. are changed, the technician should be notified in time and can be used with permission.
4.5 All kinds of materials transported to the site should be stacked neatly as required, and materials with different compositions should be listed and marked and should not be mixed.
4.6 Check carefully when preparing materials, deal with suspicious items in time and report to relevant personnel. It is strictly forbidden to add explosives and other harmful substances into the furnace.
