Four points of inspiration and configuration of medium frequency induction furnace

Yituo (Luoyang) Foundry Co., Ltd. fully implemented the green upgrade project of cupola furnace electric furnace casting technology in 2012. At present, there are 4 sets of 12.5t medium frequency induction electric furnaces, two 10t should reach the insulation electric furnace and two 10t new research medium frequency induction furnaces. . In more than a year, our company has done a lot of work in smelting process technology, equipment operation and furnace lining maintenance, and gained some experience.

First, our company mainly produces gray cast iron parts. The products involve large tractor chassis parts, as well as engine block, cylinder head and crankcase. The proportion of charge is mainly scrap steel, the proportion of pig iron is not more than 20%, and the electric furnace smelting process is carried out by adding carbonizer to increase the carbon, and the proportion of adding carbonizer is 2% to 3%. The recarburizer is used in combination with calcined petroleum coke and graphitized recarburizer, which is mainly used in the adjustment of molten iron composition and production of ductile iron castings. The electric furnace smelting adopts the feeding of the feeding car, and uses the electronic scale menu program to mix and feed. The electric furnace iron liquid is overheated at 1520～1540°C, and the silicon furnace inoculant is compounded before the furnace, and the casting material quality and quality control are relatively stable (compared with double melting).

Second, the electric furnace smelting is from the start of feeding to the condition of tapping, and the furnace time is about 80 minutes. The main factors affecting the melting time are related to the quality and size of the charge. At present, the recycled material has not been purified, and there are many slags, which have certain influence on the melting efficiency. Later, consider adding a vibration sand removing device.

Third, the use of electric furnace: the lining material is made of quartz sand dry material, the service life of each furnace is 160-180 furnaces, and the maximum is more than 200 furnaces. The main factor affecting the life of the lining is the temperature control of the molten iron. The service life of the individual heats is short, because the temperature in the smelting is improperly controlled, causing severe local erosion in the lower part. The mouth of the furnace is plastic knotted and repaired. The main problem in use is that the iron in the taphole is lining the drill iron, which causes high ground leakage value and alarm failure. Therefore, daily maintenance and inspection must be emphasized.

Fourth, the current medium frequency induction furnace equipment manufacturing and process technology is relatively mature. The main equipments of Yingda, Xinyan and other companies are manufactured in China, but the key components such as thyristors are imported and the price is high. It is hoped that the electric furnace power supply will be equipped with reliable protection devices for key components such as thyristors to reduce losses.