On the basis of thermodynamic calculations it is shown that crystallization of metals is a thermodynamic process, which takes place mainly at constant temperature. The exception is crystallization at very high cooling rates of the metal melt when the released solidification heat is not enough to stabilize the crystallization temperature of the liquid metal. In crystallization, the specific interfacial surface energy of crystals is not a constant value, but is proportional to their dimensions (bend radius).

Nanocrystals of crystallizing phases exist in the metal melt steadily. Metal crystallization aggregates nanocrystals and free metal melt atoms into microcrystals. Mechanism of dendritic crystallization of metals is proposed.

Thermodynamic calculation of formation of spherical gas bubbles different in water – wetting on flat surfaces by metal melt is made. This process consists of two stages. The first stage is formation of equilibrium gas bubble in the form of ball segment. The second stage is its swinging into a spherical bubble. Calculations were made for gas bubbles with constant volume. It is shown that Gibbs energy of spherical gas bubble formation on water – wetting metal melt substrate is three times less than on nonwettable melt substrate. Thus, gases released by solidification of the castings will preferably be formed and removed as bubbles on the molten metal surfaces of the crystallizable phases of the alloys and directly affect on their microstructure.

Various modifiers are used for non-furnace processing of cast iron. Some of them are designed for inoculating modification, which improves mechanical properties and eliminates the appearance of whiteness in castings, while others are designed for spheroidizing processing, in particular for producing cast iron with spherical and vermicular graphite. Some have both spheroidizing and inoculating properties. The main part of inoculating and spheroidizing modifiers is made on iron-silicon, Nickel and copper bases.

In addition to the chemical composition, the size of the modifier particles, as well as their shape, are of great importance for modification. The optimal size of the fraction depends significantly on the non-furnace processing technology. Thus, for the larger the bucket and the longer the casting the longer the modification effect is required. One of the methods to achieve this is to increase the particle size of the modifier to 50 mm. When intraform processing of cast iron with spherical and vermicular graphite, magnesium-containing modifiers have strict limits on the upper size (4...5 mm), and in addition, the content of small fractions (less than 0.6...1 mm) is not allowed.

The use of «heavy» magnesium-containing ligatures for spheroidizing modification of cast iron in order to obtain higher physical and mechanical properties has scientific and practical interest. Numerous studies show that for maximum effect the formation of the structure of the spheroidal graphite, dispersed pearlite metallic base of SGI (spheroidal graphite iron) relevant question is not only selection of the chemical composition of magnesium alloys, but also of the fractional composition, as well as effective method of input into the liquid melt.

The purpose of this work was to study the technological features of obtaining cast iron with spherical graphite by bucket modification of copper-magnesium ligature.

The researchers used a Leo–1420 scanning microscope, a Polam l-213 optical microscope, and a VEGA II LMU electron microscope with an INCA ENERGY 350 microanalyzer. High-speed induction melting plant, a set of equipment for analyzing the technological and mechanical properties of high-strength cast iron were used.

Earlier experimental studies have shown the real possibility of obtaining in the laboratory a «heavy» copper-magnesium alloys as the alloying of magnesium metal with copper, followed by rapid cooling with use of rolling and plastic deformation of powder alloys. Analysis of test results of samples of such alloys showed that it depends on the value of its additives into liquid iron in the structure of formed graphite phase in compacted and globular form. At the same time, the metal base of cast iron is additionally alloyed with copper, which has a favorable effect on the strength characteristics of SGI.

However, an urgent problem is the possibility of the appearance of a cementite phase in the structure of high-strength cast iron as a result of its increased supercooling due to the process of spheroidization of the graphite phase. This phenomenon is compounded by the fact that the copper-magnesium ligature, in contrast to the «light» ligature, does not contain silicon active graphitizer. This feature must be taken into account when obtaining high-strength cast iron of high grades.

The effect of heat treatment on the structural-phase state and hardness of small-sized castings made from the Cu-Cr-Al copper alloy obtained by casting in a water-cooled metal mold is studied. Using X-ray diffraction analysis, it was found that the castings consist of a matrix solid solution based on copper. The increased value of the crystal lattice parameter of the copper phase is associated with aluminum atoms dissolved in it. After a low-temperature (450 °C) tempering for 10 hours, the crystal lattice parameter of the matrix solid solution decreases, which is associated with the formation of the Al8Cr5 intermetallic compound on the surface of the casting.

It is established that after heat treatment (hardening and tempering), the hardness of castings from the Cu-Cr-Al alloy increases by 1.5 times.

The influence of crystallization conditions (continuous and centrifugal casting) of small-sized BrА1Fe4Ni4 bronze castings on the structure, phase composition, and hardness was studied. It was found by metallographic and X-ray diffraction methods that the castings consist of (α + γ')-eutectoid, α phase and AlCu, Al₂Cu₃ intermetallic compounds. The matrix phase in the alloy, crystallized by centrifugal casting, due to its higher alloying with Al atoms, has an increased value of the crystal lattice parameter, compared with the case of continuous casting. The hardness of the casting obtained by centrifugal casting increases compared with continuous casting, which is due to the formation of a more dispersed structure, as well as a large solid solution hardening of the matrix phase of the casting.

The Republic of Belarus has defined requirements for project management, which are recommended for all participants involved in project activities, and provide for the organization of a systematic approach to the development and implementation of projects involving architectural and construction activities for the construction, reconstruction and restoration of buildings and structures. Comprehensive pre-investment study of the project reduces the risk of starting an inefficient project, because in the process of developing the investment justification: the costs associated with construction and installation work are defined more accurately; engineering-geological and geodetic surveys of the territory under construction and technical conclusions based on the results of the survey of the technical condition of buildings, internal and external engineering systems of buildings are taken into account; all principal decisions are made on the supply of engineering and transport infrastructure; the project’s impact on the environment is assessed, and public discussions are held on the environmental impact assessment report with the state environmental expertise; determine the possibility and options for adjusting the parameters of the investment project, the adopted technology and architectural and planning solutions in order to improve the effectiveness of the project, if the data obtained indicate insufficient profitability of the project.

This article describes the main provisions on the implementation of the pre-investment stage (development of pre-project documentation, business plan) of an investment project implemented in the metallurgical industry.

The adhesive strength of the metal cord, i. e. the strength of its adhesion to the compound, is one of the most important indicators of the quality of the metal cord. Increasing the amount of adhesive strength allow to improve the performance of finished tires.

Determination of the adhesive strength value can be performed by different methods. All methods are based on extracting (pulling) metal cord from a block of vulcanized rubber and fixing the required load. Each method has its own characteristics that affect the amount of adhesive strength. Therefore, when conducting comparative tests, it is necessary to use one of the selected methods.

The study of factors that affect the amount of adhesive strength is necessary to identify the causes that lead to its change.

The article analyzes how the quality of the used compound affects the adhesive strength. Tests with the use of compounds with various defects were considered and carried out; probable factors leading to deviations in the adhesion strength indicators were determined.

The requirements for the content of hexavalent chromium in cements and raw materials for its manufacture are described. The problem with the utilization of dust from gas treatment plants of metallurgical plants at metallurgical enterprises is given. The influence of the chemical composition of the dust of gas cleaning plants of metallurgical plants on the determination of hexavalent chromium is established. A method for measuring the hexavalent chromium in the dust of gas cleaning plants of metallurgical plants by the photometric method is described. A method has been developed for extracting hexavalent chromium from dust at the cleaning units of metallurgical plants for subsequent photometric determination. An extraction method has been established to prevent underestimation of the hexavalent chromium content. The determination of hexavalent chromium was based on the formation of a blue-violet complex with diphenylcarbazide. Calibration was carried out on aque solutions with a known concentration of hexavalent chromium. For the preparation of calibration solutions, potassium dichromate of chemical purity was used. The concentration of hexavalent chromium in each calibration solution was carried out by a calculation method, overlapping the entire measurement range. The measurement of optical density was carried out on a photoelectric colorimeter type KFK-3, at a wavelength of 540 nm. Analysis of the obtained calibration dependence showed a good correlation. The calibration factor was calculated using the least square method. Extraction of hexavalent chromium from the sample to be analyzed was performed with water. The reducing effect of iron was eliminated with a solution of phosphoric acid. The developed technique is used when conducting certification control of dust from gas cleaning units of metallurgical plants, as well as during research.

A validation procedure was carried out. Obtained acceptable limits of repeatability and reproducibility of the method.

Optical emission spectroscopy is used to determine the mass fraction of elements such as carbon, silicon, manganese, phosphorus, sulfur, chromium, nickel, copper, aluminum, molybdenum, vanadium, titanium, arsenic, tin, boron, calcium, etc. Most of the analytical lines of the analyzed elements are located in the visible light spectrum, but the analytical lines of carbon, phosphorus and sulfur are located in the ultraviolet radiation spectrum.

Ultraviolet radiation (UV radiation) is electromagnetic radiation that occupies the spectral range between visible and x ray radiation. The wavelengths of UV radiation are in the range from 10 to 400 nm. The area of UV radiation is divided into: near from 400 to 200 nm; far from 380 to 200 nm; vacuum from 200 to 10 nm.

Structural particularities of the structure of the optical system of stationary spectrometers allow determining the mass fraction of chemical elements, including phosphorus and sulfur, with sufficient accuracy and reliability. This article discusses the possibility of determining the mass fractions of phosphorus and sulfur, the analytical lines of which lie in the area of ultraviolet radiation, using portable optical emission spectrometers.

The article describes the process of mechanical correction of cold-formed fittings produced in coils on industrial rightsized cutting machines of rotary and roller types. The main qualitative characteristics of the reinforcement are given, such as: ultimate tensile strength, offset yield stress, the ratio of ultimate tensile strength offset yield stress, conditional yield strength, total elongation at maximum load and the relative area of crumpling. To assess the effect of mechanical correction on the properties of cold-formed periodic profile fittings, statistical data is used for testing samples of fittings produced in coils and straightened before manual testing and samples of the same fittings transferred from consumer companies after mechanical correction on right-sized rotary type cut machines.

Tensile testing of samples was performed on testing machines in the laboratory of physical and mechanical tests No. 3 of the OJSC «BSW – Management Company of the Holding «BMC» in accordance with the requirements of ISO 15630-1:2010 «Steel for concrete reinforcement and pre-stressing. Test method. Part 1. Reinforcing rods, wire rod and wire» and ISO 6892:2016 «Metal Materials. Tensile test. Part 1. Method of test at ambient room temperature».

The article deals with issues related to the use of calcium carbide in steelmaking, instead of secondary aluminum and other deoxidizing materials, in order to reduce the cost of deoxidizing steel and slag.

It was assumed that reducing the content of aluminum in the metal of the reinforcing steel grade would improve its spillability, and by improving the spillability, the yield of usable metal would increase. It was also expected that as a result of the use of calcium carbide for deoxidizing the coating slag in the ladle, the degree of contamination of cord steel with non-metallic inclusions would decrease.

During the tests, the optimal amount of additive material was determined. In General, as a result of the work carried out, it was found that calcium carbide can be used for deoxidation of slag and metal during extra-furnace steel processing

The methods of adding the material are described in detail. The results of this work are presented.

The article deals with the issues of determining the thickness of layers and coatings for various purposes in metallographic research. The role of the material for filling metallographic sections in determining the layer thickness is demonstrated. It is shown that when filling the sample with plastic masses, the error in determining the layer thickness can be 0.2...0.4 microns, which is significant for thin layers. Sample preparation options for determining the thickness of titanium nitride layers with a thickness of 1 microns or less are considered. It is shown that with the optimal method of sample preparation, it is possible to visualize a layer less than 1 microns thick, and also determine its thickness in the image processing program.

Recommendations to assign steel grades most commonly used in industry and energy of the Republic of Belarus to a specific group and subgroup of the international standard ISO/TR 15608 are presented. These recommendations were made on the basis of a comparative analysis of the base metal chemical composition and its mechanical properties, given in the national and foreign standards for sheet and pipe metal rolling. Analysis of mechanical properties have been included conditions of thermal and thermomechanical treatment of the base metal. The information presented in the article can be useful for a wide range of welding specialists in documentation development for welding processes (WPS, WPQR), issuing welders attestation certificates (qualification test certificate) and other technological documentation.

The option of creating a composite material based on high manganese steel by the method of dynamic alloying in the superdeep penetration mode by flows of powder particles is considered. The dynamic effect of powdered microparticles on a matrix billet transforms the original cast steel into a composite material and leads to a change in mechanical properties.

The article deals with the comparative application of optical and raster microscopy for non-metallic objects and non-conducting surfaces. It is noted that this issue is not covered much in the special literature. There are practically no publications that compare and describe photos of the structure of materials obtained using fundamentally different microscopes, in particular, metallographic and raster. The causes of image distortion in a raster electron microscope in the study of dielectrics are considered. Comparative images of the oxidized surface, fabrics and natural leather obtained using raster and optical microscopy are presented. The advantages of optical microscopy in the study of non-conducting surfaces are shown.

Based on the simplest representations, questions of relativistic compactification of reference systems with relative virtual motion, non-locality of pseudo-reference frames of world constants and Schrödinger’s thesis on the completeness of the general and incompleteness of the particular are considered.