Thermal operation of arc foundry furnaces

Experimental data on the temperature distribution over the lining thicknesses of the walls, roof, and bottom of a 6-t arc steel-melting furnace are processed. The time dependence of the heat flux density distribution over the lining thickness is determined, and the change in the enthalpy of the lining during a heat is found. Recommendations for the rational use of the heat accumulated by the lining during furnace downtime are given.     

Concept of combined heating of scrap in shaft arc steel-melting furnaces

The modern limiting concentrations of harmful substances released in atmosphere are presented for steelmaking. The conditions of heating and gas formation in heating of metal scrap in a shaft arc steel-melting furnace are considered. A method of combined heating of metal scrap is proposed for such furnaces to decrease the pollutant emission into the atmosphere. Apart from the heat of effluent gases from a furnace, this method uses the heat of gas-oxygen burners placed in various shaft heater zones. The advantages of this method of heating of metal scrap are presented.     

Methods for increasing the efficiency of heating scrap metal in electric arc furnaces

The type of heating, which determines heat transfer from an external energy source to a metallic charge, plays a key role in the process of preliminary heating of scrap metal. The type of charge heating during preliminary heating of scrap metal mainly determines the average scrap metal heating temperature and the formation of harmful substances. This article considers the existing types of charge heating in EAF baths and shaft heaters. The types of scrap metal heating that increase the energy efficiency and weaken the ecological problems related to this process in electric furnace steelmaking units are found.     

炉料连续预热式电炉炼钢技术探讨

在废钢入炉熔炼前,利用电炉产生的高温废气进行废钢预热,节能效果明显.炉料连续预热式电炉过程实现废钢连续加料、连续预热及连续熔化,电弧加热熔池、熔池熔化废钢,与普通电炉有着很大的区别.为了实现高效节能、追求流程设备顺行及其指标优化,本文在研究炉料连续预热式电炉工艺特点的基础上,提出如下论点:应对电炉炉衬的砌筑、供电、吹氧去碳、造渣脱磷等予以重视;由于全程\     

Increasing the output and the energy efficiency of electric arc furnaces with shaft heating of metal scrap

It is proposed to equip the electric arc furnaces with shaft heating of scrap that operate with continuous scrap melting in a liquid metal with powerful gas-oxygen burner units. When scrap is heated to 800°C at a gas flow rate of 15.5 m³/t and a bath is blown by oxygen at the slag-metal boundary, fuel-arc steelmaking units can successfully compete with the best modern electric arc furnaces in capacity and have ecological advantages.     

Conversion of arc steelmaking furnaces into plasma furnaces

Chelyabinsk Girpomez. Translated from Metallurg, No. 8, pp. 29–30, August, 1988.     

Operation of blast furnaces with a bell-less charging apparatus

The goal of this article is to compare practical data obtained by charging blast furnaces with two different types of bell-less charging apparatus (BCA). The plant VSZh Koshitse has operated two large modern blast furnaces equipped with BCA from different manufacturers. Over a twenty-year period, this has allowed the plant to compare the charging conditions associated with the different methods and determine their effect on the smelting operation. Both of the BCA are modern units. The BCA of the Koshitse type is not well-known in Western Europe or other areas of the world but is the equal of the BCA made by Paul Wert. __________ Translated from Metallurg, No. 7, pp. 47–51, July, 2006.     

Control of vacuum arc furnaces

Control of a vacuum arc furnace by means of a programmed step in the melting process is described. A model of voltage control in a vacuum arc furnace was considered in [1, 2]. However, the control algorithm is associated with considerable static error. The error may be reduced using a programmed step, corresponding to previously calculated motion of the consumable electrode so as to maintain constant melting rate and a specified range of the electrode gap. By this means, blind control of melting in the vacuum arc furnace, without any feedback, is possible for ideal electrodes. In the case of nonideal (real) electrodes, however, such blind control cannot maintain the required melting parameters. Therefore, in that case, voltage feedback must be employed. Matlab software is used for simulation of the process in the case of ideal and nonideal consumable electrodes.     

Electrical optimization of superpowerful arc furnaces

Requirements on the systems controlling the electrical conditions of superpowerful arc furnaces in steel smelting are outlined. The basic principles for electrical optimization at different phases of smelting are considered. An improved mathematical model is proposed for analysis of the arc furnace’s electrical characteristics and the dynamics of the automatic control system governing electrode motion. A diagnostic system capable of identifying the phase of smelting on the basis of the harmonics of the arc currents shortens the furnace’s working cycle and reduces the power consumption.     

Acoustic characteristics of electric arc furnaces

A mathematical model is constructed to describe the appearance and development of the noise characteristics of superpower electric arc furnaces. The noise formation is shown to be related to the pulsation of the axial plasma flows in arc discharges because of the electrodynamic pressure oscillations caused by the interaction of the self-magnetic field with the current passing in an arc. The pressure in the arc axis changes at a frequency of 100 Hz at the maximum operating pressure of 66 kPa for an arc current of 80 kA. The main ac arc sound frequencies are multiples of 100 Hz, which is supported in the practice of operation of electric arc furnaces. The sound intensity in the furnace laboratory reaches 160 dB and is decreased to 115–120 dB in the working furnace area due to shielding by the furnace jacket, the molten metal, and the molten slag. The appropriateness of increasing the hermetic sealing of electric furnaces and creating furnaces operating at low currents and high transformer voltages is corroborated.