Application of rotary furnaces for melting ferrous alloys

The article presents the experience of using rotary tilting furnaces (RTF) for melting ferrous alloys, as well as for recycling of dispersed iron-containing wastes (chips, dross, sludge) to obtain high – quality casting alloys directly in the RTF or when implementing the duplex process: RTF-induction furnace or RTF-arc furnace. The main technical characteristics of RTF that developed by Belarusian scientists and designers are described. The most promising areas of application of RTF were shown. An approximate calculation of the economic effect associated with the use of RTF in the production of steel and cast iron castings is performed.

Application of Duplex Technology for Modification of Friction Pair Surfaces

The set of studies on modified superficial layer friction pair parts made of X155CrVMo12-1steel was discussed. The said layer is produced according to the duplex process of nitriding and oxidation and is investigated using methods of metallography, X-ray diffraction analysis and micro-hardness measurement based on the oblique and transverse polished sections of the studied surfaces. The results produced proved the duplex process efficiency.

CHOICE OF THE OPTIMAL CONTROL STRATEGY FOR THE DUPLEX-PROCESS OF INDUCTION MELTING OF CONSTRUCTIONAL IRON

To find effective control of the duplex process of induction melting in conditions of uncertainties, a method was suggested that made it possible to obtain optimal controls for both stages: melting and thermal treatment. It is shown how the search for an optimal melting control strategy can be performed using the theory of statistical games. At the same time, it is selected which of the melting regimes will be the best with the existing provision of the shop with charge materials. The costs of melting are the total costs, consisting of: – costs for the selected technological mode of melting (including costs for materials), – costs from the potential rejection of castings due to the non-conformity of the chemical composition of the alloy to the specified – due to the incorrectly chosen melting mode, – costs from the downtime due to the fact that the necessary amount of metal from the furnace is not delivered to the conveyor. The choice of an optimal control strategy in accordance with the proposed procedure can remove uncertainty in the evaluation of input process variables if they are taken as indicators of the charge quality. To find the optimal control at the stage of the heat treatment, a multialternative description of the final state is proposed on the basis of solving the problem of ridge analysis. This makes it possible to remove the uncertainty in the estimation of the final state, which allows a lot of optimal solutions in the sense of achieving a given quality. It is shown that such approach makes it possible not only to synthesize the optimal controller of the temperature regime on the basis of an analysis of the system of differential equations describing the control object, but also the application of the Pontryagin maximum principle to search for optimal control of the thermal treatment. The proposed method allows to determine the optimal control in the sense of stabilization for a given process parameter of the duplex process of induction melting. The resulting solutions form the necessary logical conditions for the logic control unit for the control system of the duplex induction melting process.

Features of Cast Iron Smelting in Induction Crucible Furnaces

The article describes the trend towards increased use of induction crucible furnaces for cast iron smelting. The use of gas cupola’s duplex process – induction crucible furnace – has been proved the effective direction of scientific and technical advance in the foundry industry. Gas cupolas and induction furnaces are used for cast iron smelting at the Penza Compressor Plant where in the 1960s the author developed and introduced gas cupolas for the first time in the world. In the article, the author represents the findings of the investigation on thermodynamics of crucible reduction of silicon, which is pivotal when choosing the technological mode for cast iron smelting in induction furnaces. The author proposes a new reaction crucible diagram with due account of both partial pressure and activity of the components involved into the process. For the first time ever, the electrochemical mechanism of a crucible reaction has been studied and the correctness of the proposed diagram has been confirmed.