Vol 2019, No 12 (2019)

It is proposed to consider the oxidation potential of the ladle slag coating as the factor affecting the modification efficiency. Conditions of modifiers effective influence on steel are determined. Samples of industrial steels smelted with the determined conditions accordance are obtained. The impact of new rapidly quenched modifiers with rare-earth metals on the molten medium carbon steels 40Kh and 38KhM was studied by method of viscometry. Such steels have no hysteresis of viscosity. According to the alloys influence on the liquid steel supercooling during solidification, limits of the rational using of new alloys are established.

The process of making R6M5 steel by remelting with oxygen blowing in a 20-t electric arc furnace is considered. To improve the technical-and-economic indices of the furnace operation, the following measures are tested on a series of pilot heats: the introduction of oxygen under the metal melt surface in a molten-metal bath using a consumable uncooled tube and heating of the scrap in a charging bucket by effluent gases to a temperature of 250–370°C. These measures lead to a decrease in the heat time, the metal loss, and the specific consumption of electric power and oxygen.

The state of stress in the welded joints of new nickel and titanium alloys in a high-pressure compressor during heat treatment is simulated. The QForm software package is used to simulate the results of heat treatment and to find heat-treatment conditions. The designed thermal locks made of nickel and titanium alloys are shown to minimize the technological risks of cracking and to retain the geometric sizes of the welded joints during heat treatment.

The general laws (continuity equation) and the influence of boundary factors on diffusion equations for the internal oxidation zones in multicomponent alloys are presented. The diffusion equations in a continuous oxide layer and the internal oxidation zone are given. The combined solution of these equations provides sufficiently full information about the kinetic regularities of the phase formation in the reaction diffusion zones. This solution also allows one to construct a concentration distribution of the components in the internal oxidation zone and an external oxide layer.

A mathematical model is developed to describe the electromagnetic energy transfer between the phases of an electric arc furnace. This model is used to study the efficiency of operation of a DSP-100 electric arc furnace with the coplanar arrangement of a secondary current lead for short, medium, and long arc discharges. The energy processes in the furnace are found to be determined by both the potential gradients in arc discharges and the electromagnetic coupling of the phases, which causes redistribution of the total power released in arc discharges between the phases. Recommendations for the application of a phase-by-phase controlled reactor during long-arc operation are made.

The microstructure of a 1417M alloy after magnetohydrodynamic (MHD) treatment has been studied. An electric field induced in the aluminum alloy melt is shown to cause electric transfer and to homogenize its structure. During the formation of an ingot upon MHD treatment, intermetallic phase dendrites are preferably oriented along the lines of the induced electric field.

The paper presents the results of experimental studies of the effect of high-temperature coatings on turbine and compressor blades made of high-temperature nickel and titanium alloys on the service life characteristics during gas corrosion, thermal loading, and thermomechanical loading: quantitative cracking resistance characteristics, fracture toughness K_1C, and fatigue life.

The deposition of a ceramic layer of a thermal barrier coating, which is performed by medium-frequency magnetron sputtering of targets using an experimental industrial installation in the FGUP VIAM, is considered. The microstructure of the ceramics is studied and electron microprobe and X-ray diffraction analyses of the prepared coating are conducted.

Technological techniques are proposed to process copper-smelting slags to perform zinc recovery and selective solid-phase iron reduction in tube furnaces under laboratory conditions and to melt the reduction products in arc steelmaking furnaces to form cast iron, ferrosilicium, or building steel. Cast iron milling media, building steel bars, ceramic proppants for the oil industry, and sand for concrete production are fabricated and their properties are studied. A technological scheme is developed for combined processing of slags and a set of commercial equipment is chosen. The economic efficiency of the process of production is estimated.

The additive articles made from the powders fabricated by electric discharge dispersion of the wastes of cobalt–chromium alloys are studied. These articles are shown to have a fine-grained structure without inclusions and discontinuities, and their porosity decreases with increasing fusion temperature. An increase in the fusion temperature 120°C in the temperature range under study is found to decrease the porosity of the articles by a factor of 4.5.

The possibility of predicting the fracture of large forgings made of a heat-hardenable Cr–Ni–Mo steel with a different-scale structure is estimated.

The influence of export–import operations on the steelmaking production and the consumption of steel products in the world after the 2009 global financial crisis is estimated. Export is shown to prevail over import in terms of the rolled products in CIS, Asia and the world market, and export operations with first-stage cast steel products are most popular on the CIS market. The European market is characterized by a lower concentration of contractors participating in international export–import operations in comparison with the world steel market and its regional segments. The possibilities of expansion and intensification of metal trading on the world market are analyzed using the concept of bifurcation points for the distribution of a product on a market and information about this product.