Vol 2018, No 6 (2018)

The results of the manufacture of high-purity scandium and critical analysis of the existing technology of rare-earth metals (REMs) are reported. Carbothermic and distillation technologies and equipment for manufacturing REMs are considered. An optimizing calculation of electric-furnace condensers is reported.

A full technique of production of a 29N26KKhBTYu-VI precision alloy is developed and implemented. A 500-kg ingot has been melted in Russia for the first time. This ingot is used to form an experimental batch of forged billets 90 mm in diameter and to fabricate hot-rolled metal billets 20 and 30 mm in diameter. The temperature–time deformation conditions, including data on the ductility of the alloy at the deformation temperature and the technological parameters of each processing stage, are studied. A comprehensive metallographic investigation of the alloy is performed.

A modern technique is proposed to calculate the electrical parameters of the characteristic sections of the power-supply circuits of ore-smelting furnaces, namely, laminated stacks, flexible part, and tubular busbars of the power-supply circuit of an electrode. This technique is based on the results of numerical simulation of the electromagnetic field of a set of conductors with the ANSYS software package and on a mathematical model for calculating the inductance of a system of two rectilinear conductors arbitrarily located in space.

Differential thermal analysis is used to study the processes that occur during the interaction of erbium fluoride with potassium chloride–sodium fluoride melts, which are used as a flux for the metallothermic synthesis of an Al–Er master alloy. The flux compositions under study are used to synthesize Al–Er master alloys and can be recommended for the preparation of intermediate alloys with a high alloying-element content (15 wt % or more). Experimental studies allowed us to synthesize master alloys having a new chemical composition. The microstructure and the chemical and phase compositions of the master alloys are studied.

Steel 05Kh21AG15N8MF forgings 250 mm in diameter with a nitrogen content higher than 0.60%, which is necessary for a high-strength austenitic structure, are fabricated by plasma arc remelting. An experimental batch and strips are made of this steel. The chemical composition, the macrostructure, the mechanical properties, the intergranular corrosion resistance, and the hardness of the forgings are studied.

The shift of the liquid metal bath with respect to the axis of a melted electrode during the passage from an alternating current to a direct current is considered. A method is proposed to stabilize the liquid metal bath using the centrifugal forces induced by the rotation of a consumable electrode. The experimental data are used to calculate the optimum centrifugal force, and a computer model is developed with the Design Exploration unit of the Ansys Multiphysics software package. The electromagnetic force is determined at various distances of a molten drop from the electrode. The simulated data are used to perform electroslag melting with a fixed liquid metal bath along the ingot axis. The geometry of solidification front is determined and the possibility of controlling a crystal structure is shown.

The influence of the conditions of complete and incomplete postwelding annealing on the strength properties of the welded joints of a VT41 alloy is studied. These annealing conditions are developed for the ring welded joints of a VT41 alloy. The optimum conditions are determined for the production of large welded joints of a VT41 alloy for a high-pressure compressor in an advanced engine. The mechanical properties of the base and weld metals are compared after complete and incomplete postwelding annealing. The microstructure of the welded joints after heat treatment is investigated.

The properties of the coatings fabricated by plasma-jet hard-facing with a powder mixture of the dispersed wastes of VK8 hard alloy, R6M5 high-speed steel, and Kh15N60 nichrome taken in the same proportions are studied. The microhardness and the wear resistance of coatings are higher than those of the 30KhGSA steel substrate by a factor of 1.4 and 1.3, respectively. The coatings have a very small number of pores, and the arithmetical mean deviation of the coating profile is Ra = 0.73.

The electrical conditions of operation of ac and dc 0.5- to 25-t furnaces, namely, the installed, active and net powers, the maximum electric arc voltage, the electric arc operating current, and the electrical efficiency, are considered and compared. The parameters of a dc twin furnace, where one power supply is used for two furnaces and the periods of melting and finishing of a liquid metal in these furnaces are separated in time, are analyzed.

Heterogeneous different-scale structures in large forgings made of a heat-hardenable Cr–Ni–Mo steel are compared. The effect of heterogeneity on the properties of the metal is evaluated.

A technology is developed to refine the wastes of cast high-temperature alloys in the form of scrap, crop ends, and chips for the production of cast bars from in order to involve these wastes in making cast high-temperature alloys. The quality of the alloys melted using the refined wastes meets the requirements of the specifications.

The prospects of development of the enterprise are analyzed using the information on its industrial and economic activity in 2009–2016; this time period is characteristic of the crisis and postcrisis stages in the world and Russian economics. The technical-and-economic indices that reflect the most important aspects of the enterprise activity are estimated. The long-term measures taken by the management and the staff allow them to develop business dynamically in strategic perspective.