Views:0 Author:Site Editor Publish Time: 2021-06-07 Origin:Site
Compared with foreign EAF steelmaking, China's EAF has always been the main production force of special steel. With the increasing quality requirements of special steel in domestic manufacturing industry, improving the level of EAF steelmaking process and equipment in China has become the key to improve the quality of EAF steel products. On the one hand, due to the special furnace structure, electric arc furnace melting pool stirring strength is insufficient, oxygen utilization rate is low, final slag (FeO) content is high, the molten steel peroxidation is serious; On the other hand, EAF steelmaking process includes the removal of residual elements, P, S, N, H and inclusions, which involves the matching and optimization of the whole process, and is a challenge to the technology of smelting high-quality steel in EAF steelmaking process. It is not difficult to find from the development of EAF steelmaking technology in recent years that EAF steelmaking has made great progress in cleaning smelting on the basis of the original high efficiency and energy saving smelting, and the product quality has been significantly improved, which is of great significance to promoting the construction of the production platform of EAF steelmaking flow cleaning and purification in China.
An arc is an arc discharge of gas. Gas arc discharge is characterized by a very low voltage between poles, but a very large current through the gas, with dazzling white light and a very high temperature in the arc region (about 5000K). The huge current density comes from the emission of hot electrons from the cathode, as well as the self-emission of electrons, that is, there is a layer of positive ions near the cathode, forming a strong electric field, so that the cathode automatically emits electrons. A large number of electrons collide with gaseous molecules between the poles to ionize them, producing more positive ions and secondary electrons. Under the action of electric field, they collide with cathode and anode respectively, and the result is high temperature. The temperature of the cathode is lower than that of the anode because some energy is used in electron emission.
The high temperature also occurs between the poles due to the exothermic combination of some positive ions and electrons. Electric arc furnace is the industrial furnace that smelts metal with this principle. Electric arc furnace in vacuum environment is vacuum arc furnace. Vacuum arc melting adopts high current and low voltage, which belongs to short arc operation. The general arc voltage is 22 ~ 65V, and the corresponding arc length is 20 ~ 50mm (the latter is large ingot). Since the success of the platinum wire smelting experiment in 1839, people began to study the smelting of refractory metals for more than one hundred years. The vacuum arc furnace was officially used in industry in 1953. Until 1956, titanium was smelted in non-consumable furnaces in the United States and many countries in Europe, and steel was smelted in consumable furnaces in 1955. Around 1960, the weight of ingot produced by self-consumption furnace has reached more than 30 tons, and began to take shape. The current development can be represented by the vacuum self-consumption furnace manufactured by the American company Kangsac. In order to increase productivity and equipment utilization, the two furnaces share a single set of main electricity