In the casting workshop for the production of cast iron parts, the use of cupola + electric furnace double smelting or medium frequency electric furnace smelting of molten iron has been arguing in the industry. Both have their own advantages and disadvantages, but there is an indisputable fact that it is efficient in recent years. Reliable, flexible mid-range electric furnace equipment occupies the vast majority of the domestic market. How to choose the right electric furnace in the engineering design, there are some problems that need attention in the design, this article will be discussed.

1Select cupola or medium frequency electric furnace

A series of redox reactions occur in the cupola smelting of molten iron. There is a certain metallurgical process for the molten iron, and the molten iron in the electric furnace is only a melt remelting process, which determines the quality of the molten iron of the cupola in some respects than the electric furnace. Slightly better. The use of electric furnace to obtain high quality and stable molten iron, the quality of raw materials is good, but under the same conditions, the one-time investment of electric furnace is only 1/2 of the cupola. If there are many varieties of castings and different materials, the electric furnace is used.

Product flexibility will be high. Under normal circumstances, the electric furnace is often used when the productivity is below 10 t/h, and the cupola can be considered when the pressure is above 15 t/h. The electric furnace is a large power consumer, and the electricity consumption per ton of molten iron is about 600 kW·h. Therefore, when selecting the electric furnace, it is necessary to consider the local power supply conditions, often

The pull limit current will affect normal production.

2 electric furnace equipment composition

The electric furnace is mainly composed of two parts: mechanical equipment and electrical equipment, and is equipped with a special oil-immersed transformer. The mechanical equipment includes the furnace body, the tilting device and the water cooling system; the electrical equipment includes the intermediate frequency power supply, the compensation capacitor and the control protection system. The electric furnace smelting generates an alternating magnetic field by the induction coil of the furnace body, and generates an induced current in the metal furnace material to make the iron material

The heat is melted and the temperature of the molten iron can reach 1 550 °C. The water cooling system is the life guarantee for the reliable operation of the electric furnace. It plays the role of cooling and cooling the furnace body and the power supply cabinet. The furnace body and the power supply are provided with two sets of cooling systems, which are divided into water-cooled closed circulation cooling. , the internal circulation system is closed, often using distilled water;

The external circulation system generally uses demineralized water or tap water depending on the water quality of each place.

The power cabinet has two types: current feed parallel inverter mode and voltage feed series inverter mode. Due to different design lines, the rectification, smooth wave, inverter mode and load resonant circuit connection method are different.