Casting, forging and welding are the three basic thermal processing processes that provide most of the parts blanks for the modern equipment manufacturing industry. With the rapid development of mass-produced automobiles, construction machinery, rail transit and other products, the foundry industry and the forging industry are welcoming opportunities for development. After nearly 30 years of rapid development, casting molding process, sand treatment process, cleaning process and smelting (insulation) equipment to automation, energy-saving, environmental protection development, product upgrade and transformation is imminent.
At present, the domestic intermediate frequency melting furnace melts 550 to 650 kW·h of electricity per ton of molten iron, and the foreign advanced smelting equipment can reduce the power consumption per ton of molten iron to 500-560 kW·h. To narrow the gap, we need to implement the following aspects: medium frequency induction furnace, power distribution equipment, circuit type and its control system, electric furnace capacity frequency and power density, furnace structure, and cooling water system manufacturing process, operation and management. Standard operation, scientific management.
Medium frequency smelting (insulation) has been vigorously promoted in terms of energy saving and environmental protection. In recent years, it has achieved double smelting (insulation) with hot air cupola, and the short process of casting is a new process promoted by the national industry. Vigorously develop new energy-saving intermediate frequency power supply, and the supporting exhaust emission treatment device is an environmentally mandatory requirement. Energy conservation is a systematic project that requires equipment manufacturers, manufacturers and supporting manufacturers to work together to improve the technical level and management level. Based on the rare development opportunities in China's current price segment, continuous technological innovation, promote structural adjustment, product upgrades, correct use of standards, and maximize the potential of equipment, I believe that meeting or close to foreign advanced equipment technology level will be just around the corner.
The following takes the induction melting furnace as an example to illustrate the precautions of the application enterprise in use:
(1) The medium frequency induction furnace should use a dedicated rectifier transformer to increase the supply voltage and limit the no-load operation of the transformer.
(2) Standard installation, shortening the connection between high voltage, transformer, intermediate frequency power supply and electric furnace, using T2 copper or oxygen-free copper with high purity, especially induction coil and water-cooled cable, increasing the cross-sectional area can effectively reduce the current Heat loss.
(3) Select an appropriate capacity and frequency intermediate frequency electric furnace according to the casting process, increase the power density to improve the melting efficiency and reduce the additional loss.
(4) The steel shell furnace with the furnace cover is preferentially selected to reduce the heat loss and electromagnetic loss of the furnace wall and the furnace mouth. The furnace body joints prevent short-circuiting of metal contacts during operation.
(5) Formulate a reasonable casting process, from the modeling, material selection, melting, pouring, heat treatment, cleaning and other standard process operations, scientific management to reduce energy consumption.
(6) Strengthen equipment management and maintenance, reduce the failure rate, and ensure smooth production.
(7) Always check whether the contact parts of the conductive systems are in good contact, especially if the screws at the connection between the water-cooled cable and the induction coil are tight. The insulation table and the insulated boots must be inspected once a year.
(8) During the smelting process, it is forbidden to stop power and stop water. During the smelting process, the water temperature and water pressure should be paid attention to at any time, so that the water pressure is kept at 0.1-0.3 MPa and the effluent temperature is kept below 55 °.
(9) When feeding, the cold and wet charge should be dried first, and can not be directly added into the melt. It is best to avoid metal cutting in the first furnace, because the metal cutting can penetrate into the lining gap; the furnace must be heated to 1000. When the temperature is around °C, the molten iron can be poured, and the heating of the furnace can be added to the iron block for induction heating.
(10) The freezing and sealing time of the furnace material should not be too long, so as to avoid causing the furnace explosion accident; after sintering the furnace lining, it is recommended to use 30~50% of rated power and continuously work more than 5 furnaces.
