Carburization of crude steel from a superpowerful arc furnace

Optimal carburization principles are formulated for the production of pipe steel when using a superpowerful arc furnace. Laboratory and industrial research confirms the significance of combining reduction and carburization, the quality of the material used for carburization, and the time at which the carbon content is corrected. The use of silicon carbide for combined carburization and reduction of the crude steel proves effective.     

Multicriterial optimization of the batch composition for steel-smelting arc furnaces

A strategy for optimization of the batch composition in steel-smelting arc furnaces is considered. In this approach, the optimization problem is divided into two parts: the first step is to optimize the ratio of metal scrap and hot metal; the second is to optimize the chemical composition of the scrap in terms of the chromium, nickel, and copper content. As an example, this approach is applied to OAO Magnitogorskii Metallurgicheskii Kombinat (MMK), in terms of the requirements for each grade of steel. A generalized protocol for application of the optimization strategy is presented.     

Conversion of arc steelmaking furnaces into plasma furnaces

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

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.     

Slag oxidation in arc furnaces

In the electrosmelting shop at OAO MMK, the smelting of steel in powerful DSP-180 arc furnaces introduced in 2006 continues to be refined. Industrial research is conducted to establish how the content of the iron oxides FeO and Fe₂O₃ in the slag depends on its total oxidation. As a result, the dependence of FeO/Fe₂O₃ on the total slag oxidation may be described. It is established that the total slag oxidation does not depend on the consumption of injected carbon in frothing the slag. Analysis of the waste gases in the same smelting period shows sharp increase in the content of carbon oxides (especially CO) and the temperature. On account of the poor assimilation of the injected carbon by the melt, much of it is oxidized in the gas phase.     

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.     

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.     

Adjusting characteristics of electric arc furnaces

The dependences of the electric and electrotechnological parameters of electric arc furnaces on the arc length in different heat periods are considered.     

Electric arc in three-phase metallurgical furnaces

The theoretical and practical assumptions relative to the studies of electric arcs in steel-melting furnaces presented in journal Electrometallurgiya in 2011–2012 are subjected to a critical analysis. Based on classical concepts and the author experiments, the concept is presented regarding to the phases of the state and parameters of arc discharge in the ac electromagnetic field of a three-phase system. Industrial methods of eliminating the injurious effect of flash arc on furnace lining and the furnace efficiency are considered.     

Processing exhaust emissions from arc furnaces

A new treatment system for the exhaust emissions from arc furnaces is described. This system ensures complete combustion of CO and H₂, condensation of the steam, coagulation and spheroidization of the dust and slag particles, their cooling to sintering temperatures, and the utilization of 95% of the solid particles in the deposition chamber. That significantly reduces the erosional wear of the gas lines, extends their working life, and reduces water consumption.     

Utilization of hot metal in arc furnaces

The advantages and disadvantages of hot metal in the electrosmelting of steel are considered. It is energetically expedient to replace some of the metal scrap with hot metal. Methods of introducing hot metal in the arc furnace are analyzed. Practical recommendations are made regarding the use of hot metal in electrosmelting. The hot metal used in electrosmelting at six metallurgical plants is subjected to chemical analysis.     

Prospects for synthetic composites in arc furnaces

The prospects for the use of synthetic Fe–O–C composites in arc furnaces are analyzed. It is found that, if components that are traditionally used individually are combined together in ingots or briquets, their behavior changes significantly and their effectiveness is improved. That permits complete utilization of iron-bearing production waste and the more extensive use of iron ore in arc furnaces.