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.

Based on thermodynamic calculations, it is shown that metal melting is an equilibrium process that occurs at a constant temperature. In melting, microcrystals mainly disintegrate into nanocrystals. Metal melt is a twophase system consisting of nanocrystals and atomic gas. Nanocrystals ranging in size from one to hundreds of nanometers exist stably in the metal melt.

Modern conventional notions of metallic melt structure are associated with clusters that have no interfacial boundaries. The maximum time of formation and life of the cluster is 10–7s. Clusters are formed statistically, randomly. According to probability theory, even an elementary cubic crystal cannot be formed in a time of 10–7c. The probability of forming a cluster with 100 atoms is zero. It should be considered that the metallic melt is mainly composed of nanocrystals.

The global competition, unstable situation in the world market of rolled metal products, as well as increasing with each day the requirements of consumers of products pose complex tasks for the manufacturer, which must be solved in the shortest possible time. One of these tasks is to expand the range of rebar rolled products in the conditions of the variety rolling shop no. 1 on the continuous small-grade rolling mill 320. Until recently, rolling of reinforcing profiles with a diameter from 10 mm to 40 mm was carried out at the 320 rolling mill. In order to expand the range of rebar products, work was carried out to develop a production technology for profile no. 8 rod fittings with thermal hardening in the mill line for class 500.

According to TU 14-1-4486-88 and TU 14-1-5490-2004, in accordance with international standards DIN EN 10263-4, OJSC «BSW – Management Company of the Holding «BMC» produces hot-rolled products of the following grades of steel: 20Г2Р, 

30Г1Р, 20MnB4, 30MnB4 and 32CrB4 microalloyed with boron. They are used for the manufacture of fasteners instead of previously used steels 35X, 38X and 40X. The use of boron-containing steels reduces the surface defects of hardware; to increase the stability of the mechanical properties of bolts, screws, studs, strength class 8.8 and 10.9 by GOST 1759.4-87; to achieve a high level of toughness at negative temperatures. It is shown that steel 20Г2Р provides stable mechanical properties of products up to M27 (in contrast to steel grades 35X, which are designed exclusively for bolts of class M16 8.8). The boron-containing steels in the delivery state with the structure of granular perlite have high technological plasticity – in the cold, the bolt head is formed and the thread is rolled without tearing in the thread hollows, as is the case with chromium steels of type 40X. It was found that their ductility increases due to the low content of carbon and chromium, as well as the formation of dispersed carbonitride-boride phases of a globular form.

Seamless hot – rolled pipes are a popular metal product on the world market. During operation, pipelines are subjected to cyclic loads associated with temperature fluctuations, vibrations near compressor stations, and pressure drops in the transformed medium. One of the ways to ensure high performance properties is to manage the quality of pipe metal, including that laid in the process of metallurgical production. All the basic physical and mechanical properties of metal materials are structurally sensitive and significantly depend on both the grain size and the degree of uniformity of the grain structure, that is, on the different grain sizes. For metallographic research, samples of pipes with the size of 70,0×12,5 mm of S460NH steel were selected with satisfactory (#1) and unsatisfactory (#2) results of the impact. It was found that the inhomogeneous (multi – grained) microstructure in sample #2 was the reason for obtaining unsatisfactory results of the impact. As a result, it was found that one of the most important characteristics that can guarantee stable and satisfactory results of mechanical characteristics, in particular the impact performance, is a homogeneous grain structure.

The article presents the experience of development and application of enterprise standard samples (ESS) of monolithic and dispersed materials for spectral and chemical methods of steel analysis. The procedure for the development of ESS is described in detail: development of technical specifications for ESS in accordance with the requirements of GOST 8.315, preparation of ESS material, study of the uniformity of ESS material, establishment of metrological characteristics of ESS, preparation of a report on the development of ESS, verification of technical documentation for ESS and metrological examination of documentation, approval of ESS and its registration.

Discusses the problems of protecting the goods during transport from exposure to high humidity and ways of its solutions; the presence of some consumers ‘ requirements for adherence to the maximum values of humidity and confirmation of its actual value in the packed products; the use of paper humidity indicators to control the environment during transit; the principle of operation of the indicator based on the change in color of cobalt salts depending on the composition of the crystalline.

There is a lack of methodology for quality control of paper humidity indicators. The method developed by the laboratory of OJSC «BSW» – Management Company of the Holding «BMC», to determine their sensitivity and accuracy is given. The essence of the test is to assemble an installation that provides a certain value of air humidity. To do this, we use solutions of sulfuric acid of the appropriate concentrations. Air is passed first through water, then through solutions and fed into a flask with an indicator. Depending on the humidity of the supplied air, the corresponding indicator points change colour. Sensitivity and accuracy are evaluated on a colour scale.

Evaluation of applicability of 20MnCrS5 steel for gears of transmissions of mobile machines, manufactured according to European standard EN 10084 was carried out. Experimental and virtual simulation of hardenability of the steel according to the updated method was realized. The assessment of the applicability of 20MnCrS5 case-hardening steel for gears of the domestic mobile machines was made by the criterion of obtaining the cross section of the tooth structures with a hardness 32 HRC for core, 50 HRC for semi-conversion zone, 61–63 HRC for the diffusion layer excluding other physical and mechanical properties of steel.

It is established that at the content of alloying elements close to the maximum limit, the use of this steel is possible for gears with a module up to 10 mm.

The article proposes and theoretically justifies a method for bending high-strength steels with compression. The technology allows to get parts from high-strength steels without cracks along the bending line. In the case of bending according to the proposed method, the deformation is carried out by the combined action of longitudinal and lateral forces. Equitations are derived showing the stress distribution over the cross section in the deformation zone. The article proposes and theoretically justifies a method for bending high-strength steels with compression. The technology allows you to get parts from high-strength steels without cracks along the bending line. In the case of bending according to the proposed method, the deformation is carried out by the action of longitudinal and transverse forces. Equitations were derived for finding the longitudinal compressive force at which the neutral layer in the workpiece moves to the outer surface based on the equations of stress distribution. Equitations are derived for finding the moment created by the longitudinal compressive force, as well as the moment formed by the action of compressive stresses, which made it possible to derive the equation for the external bending moment during bending with compression. Equitation is derived for finding the shoulder of the force action creating an external bending moment. Equitation is derived for finding the force of the punch for bending with compression.

The results of the analysis of theoretical and experimental studies of methods for producing permanent joints of dissimilar metals and alloys are presented, as well as the advantages, implementation problems and prospects of using friction stir welding to join titanium and aluminum alloys. It is noted that most studies focus on friction stir welding of light metals such as aluminum, copper, magnesium and their alloys. Despite the great scientific and practical interest, the friction stir welding processes of alloys and metal-matrix composite materials based on aluminum and titanium have been studied less thoroughly and require additional attention.

Given the variety and complexity of friction stir welding, the lack of a correct assessment of the reactivity, properties and design features of aluminum and titanium alloys can lead to a number of problems associated with a change in the structure of materials and defects in the welding zone, which is accompanied by the inevitable deterioration of the mechanical characteristics of the finished joints.

The problem of the formation of cracks and the conditions of their origin in the cast of metal products have been widely studied in world practice, but the real mechanism of this process is not yet clear enough that it could be applied in production. Hot cracks – one of the most common and the most detrimental defects of steel castings, leading to a significant increase in the cost of products. The formation of hot cracks in steel castings depends on many factors, including the chemical composition of steel, the presence of non-metallic inclusions and gases, conditions of deoxidation and solidification of steel, etc. Therefore, special attention in the real conditions of production should be given to the metallurgical side of the issue. There is no quantitative measure of steel purity in the books of steel, which is divided into chemical, defined by the chemical analysis, and metallographic, defined by the content of non-metallic inclusions. The effect of the general purity of steel on the characteristics of destruction is studied sufficiently, but the data on the individual impact of impurities is very incomplete.

In many respects, pure steel has a clear advantage over steel with harmful impurities. This applies to all mechanical properties associated with destruction or processes occurring on the edge of grains. The cardinal way of obtaining cleaner steel, including the reduction of impurities of non-ferrous metals, is the use of pure original charge mixture.

The article discusses the topical problem of cracking formation after chemical-thermal treatment in the material of sun gears of the second row of quarry dump trucks BELAZ, obtained by the method of CESR rolled steel 20X2H4А, the possible impact of small concentrations of non-ferrous metals (Pb, Zn, Sn, Bi, As, Se) on the development of external and internal cracks in castings and on structural heterogeneity of steel after CESR.

The obtained results allowed to draw conclusions about the impact of non-ferrous metals on the formation of cracks in castings and to establish their limited quantitative characteristics. Based on the results, measures have been proposed to minimize the impact of small amounts of non-ferrous metals on the formation of cracks in castings.

The technology of helical reduction with reverse correction is presented. The key difference of the technology is the change in the feed angle during the reduction process to the region of negative values, which allows reverse correction (reduction in the region of small feed angles) and remove the workpiece from the roll gap. This technology can be used to obtain axisymmetric billets of variable profile. The main parameters that determine the reverse correction process are the rotation speed of the rolls, the rate of change of the feed angle, as well as the dimensions of the rolls and the workpiece. When the feed angle changes (in particular during correction), the workpiece continues to move in the axial direction, which makes it necessary to evaluate the magnitude of this movement. In this work, an accurate calculation of the length of the reduced part of the workpiece with a change in the feed angle is carried out.

The research methods for extraction of palladium from waste electrolyte solutions with the use of chloronitric extraction are described. The methods of investigation of the purification from harmful impurities by selective precipitation to obtain a refined palladium powder are given, the parameters on the technological processes are defined, use of the new technologies and equipment used are justified

A study of the mixed 07С11-KВ fabric (produced by Mogotex) with a coating of steel 12X18H10T, obtained by the method of pulsed cathode arc deposition in a vacuum of 3.5×10^–3 Pa, was conducted. It is shown that optical microscopy has a number of advantages in studying the surface morphology of such objects as compared to scanning electron microscopy. The most contrast image is formed using dark-field illumination. When coating is applied, a droplet phase is formed, the droplet sizes vary from 2 to 10 microns. By the method of electron paramagnetic resonance, it has been established that the spectrum of coated fabric has an asymmetrical spectral line with a width of 101 mT, which indicates a high concentration of magnetic resonance centers and a significant resonant absorption of microwave energy. Resonant absorption at low magnetic fields is determined by clusters of iron, nickel, chromium, titanium, etc., with weak nonresonant absorption. The specific surface resistance of the fabric (side 1 / side 2) is 3.3×10⁵ ohm and 5.6×10⁵ ohm, respectively.

The use of industrial waste is one of the main problems of the modern economy. In Belarus, there is no primary metallurgical processing of natural raw materials, so the use of secondary materials and production waste is a very relevant and important task for the industry, given into account that the cost of metals extracted from secondary raw materials is several times less than the primary ones.

One of the types of such raw materials is tin-lead dross (ash), which consists of tin and lead oxides with inclusions of the metal component beads. The most valuable element in dross is tin, the price of which is much higher than the cost of many non-ferrous metals. The aim of the work was to study the influence of various technological factors on the metallurgical output during the processing of tin-lead ash into solders and ligatures.

In this regard the results of previous studies related to the extraction of tin and lead in the processing of secondary raw materials were summarized, and new data on technological methods for deeper metallurgical processing of dross (ash) were presented. This allowed them to develop options for obtaining high-quality solder type POS 61 and ligatures.

One of the common technological schemes for the laser processing of metal parts is laser «glazing» of the deposited thin layer of powder on the substrate, which makes it possible to obtain microcrystalline and amorphous structures in thin surface layers of parts. Pulse melting of small volumes of metal on the surface provides homogeneous liquids (melts), which, after crystallization, can fix the structure of a liquid with unique properties.

The presence of three energy input ranges for pulsed laser surface treatment (ILPO) has been established. At an average level of energy input, a process of laser surfacing of the material occurs, while a high adhesive bond between the coating and the workpiece is fixed. The deposition of an amorphized iron-based alloy coating on a metal base of St3, 45 20X13 steels begins at a laser radiation density on the treatment surface of 1800–2000 W/mm2, and alloying at 3500–4000 W/mm2. With ILPO, the laser exposure zone (ZLV) has a layered structure – the fusion zone (ZO), the heat-affected zone (HAZ), and the source material zone. To obtain an amorphous-crystalline structure of the coating, the laser pulse frequency should not exceed 3–8 Hz.

The article describes the requirements for lubricants (release coatings) used in injection molding of aluminum alloys and polymeric materials. A methodology for conducting research to determine the tribotechnical characteristics of materials used in the development of the composition of a lubricant for injection molding aluminum alloys and polymer products, as well as the results of a study of tribotechnical characteristics (friction coefficient) are presented. It has been established that as materials used in the development of a multifunctional lubricant composition for casting aluminum alloys and polymer products, it is advisable to use a fraction of soap stock and fus after their preliminary sedimentation (at least 3 months). It is shown that the smallest value of the coefficient of friction at the time of indenter breaking on the surface of the steel disk was obtained using a fus. Moreover, the value of the coefficient of friction is 14–33% lower than the same indicator for other studied lubricants (petroleum jelly, PMS-100 and soap stock). It was found that in the mode of reciprocal movement of the indenter on the surface of the steel disk, the coefficient of friction when using a fus is 1,7–3,3 times lower than when using Vaseline, PMS-100 and soap stock as lubricant.

To create friction pairs operating in severe working conditions, composite materials are now increasingly used. Composite materials obtained with the use of casting technologies are of interest due to the possibility to manufacture wide range of compositions at low price compared to powder metallurgy. Despite the fact that many composite materials have been sufficiently studied, it is of interest to develop new areas of application and give them the properties required by the consumer. In the present work the composite materials on the basis of silumin reinforced with copper granules were considered. Attention was paid to the interaction between the matrix alloy and the reinforcing phase material as determining the properties of the composite material. The analysis of distribution of the basic alloying elements in volume of composite material and also in zones of the interphases interaction is carried out. The analysis of the possibility of obtaining a strong interphase zone of contact between the reinforcing component and the matrix material without significant dissolution of the reinforcing material is carried out.

The results of the study of working conditions of workers in non-ferrous casting shops are presented. It is shown that the main production factors of working conditions are noise, vibration, dust, gas, air temperature, the intensity of infrared (thermal) radiation, the severity and intensity of the labor process. The results of the research have shown that all workplaces have exceeded the permissible values for noise, dust content in the air of the working environment, the intensity of infrared (thermal) radiation and air temperature.

It is noted that the work performed due to the severity and intensity of the labor process can negatively affect the health of employees.

The results of the study of working conditions in heat-treating workshops are presented. It is shown that the main production factors of working conditions are noise, vibration, dust, gas, air temperature, the intensity of infrared (thermal) radiation, the severity and intensity of the labor process.

The results of the conducted research have shown that all workplaces have exceeded the permissible values for noise, the content of harmful substances in the air of the working environment, the intensity of infrared (thermal) radiation and the air temperature. It is noted that the work performed due to the severity and intensity of the labor process can negatively affect the health of employees.

The results of the study of emissions of harmful substances from sources of foundries with different production patterns are given, the share of foundry shops in emissions is determined, calculations of dispersion of harmful substances in the atmosphere are made, and air pollution is estimated in nearby residential areas and enterprise territories.

The assessment of the share of foundries in environmental pollution by machine-building enterprises showed that they make up about 82% of dust, about 60% of carbon oxide, about 70% of nitrogen dioxide, about 93% of phenol, formaldehyde, etc.