Metallurgical Research Articles

Optimal Control of the Dynamics of Physical and Chemical Processes of Blending and Melting of Copper Concentrates

This paper presents the developed model of dynamics of the physicochemical processes of electromelting of copper concentrates, which was obtained taking into account the available a priori information, which makes allowance for the main features of an object and describes the change of the basic variables of the process state (quantitative aspects of material flows and power, the composition of charge, matte, and slag). Such a model can be used in the field of automation of technological processes in metallurgical and mechanical engineering, and manufacturing. Due to the complexities of the technological process, it was advisable to use classical methods.

Minimizing Porosity in 17-4 PH Stainless Steel Compacts in a Modified Powder Metallurgical Process

Nowadays, powder-based manufacturing processes are recognized as cost-efficient methods frequently employed for producing parts with intricate shapes and tight tolerances in large quantities. However, like any manufacturing method, powder-based technologies also have several disadvantages. One of the most significant issues lies in the degree of porosity. By modifying the morphology of the gas-atomized spherical 17-4PH stainless steel powder via prior ball milling and then raising both the pressure of cold compaction (1.6 GPa) and sintering temperature (1275 °C), the porosity could be reduced considerably. In our novel powder metallurgical (PM) experimental process, an exceptionally high green density of 92% could be reached by employing die wall lubrication instead of internal lubrication and utilizing induction heating for rapid sintering. After sintering (at temperatures of 1200, 1250, and 1275 °C), the samples aged in the H900 condition were then mechanically tested (Charpy impact, HV hardness, and tensile tests) as a function of porosity. Sintering at 1275 °C for one hour enabled porosity reduction to below 4%, resulting in 1200 MPa yield strength and 1350 MPa ultimate tensile strength with significant (16%) fracture strain. These values are comparable to those of the same alloy products fabricated via ingot metallurgy (IM) or additive manufacturing (AM).

Influence of nickel plating on the welding metallurgical mechanism, microstructure, and shear performance of C101/80Au20Sn/C101 solder joints

Herein, electroplated and electroless plating processes were used to plate nickel (Ni) on the surface of C101 alloy, which is a low-carbon steel with a carbon content of approximately 0.1% and Fe primarily contributing to the rest of the content and which is commonly used in metal packaging, and electroplated Ni and electroless Ni C101/80Au20Sn/C101 solder joints were prepared. The welding metallurgical mechanisms, microstructures, and shear performances of the two types of solder joints were investigated through experimental observation, material characterization, shear testing, and finite-element analysis (FEA). The diffusion of Ni atoms within the two platings was evaluated using first-principles calculation. Results indicated that the atomic arrangement of the electroplated Ni layer was polycrystalline, whereas that of the electroless Ni layer was primarily amorphous. The orientation of Ni grains in the electroplated-Ni joints affected the growth of (Ni,Au)3Sn2 throughout the welding metallurgical process. The [111] orientation suppressed the growth of (Ni,Au)3Sn2, resulting in a discontinuous distribution of (Ni,Au)3Sn2 at the Ni/solder interface and considerable variations in the thickness of (Ni,Au)3Sn2. Amorphous Ni in the electroless Ni layer promoted the growth of (Ni,Au)3Sn2, resulting in a continuous (Ni,Au)3Sn2 layer having a relatively uniform thickness. The shear strength of the electroplated-Ni joints was considerably lower than that of the electroless-Ni joints. FEA results demonstrated that the locations of stress concentration in the electroplated- and electroless-Ni joints were at the (Ni,Au)3Sn2/solder interface and within the solder matrix, respectively. First-principles calculations showed that the diffusion performance of Ni atoms in the electroless Ni layer was considerably superior to that of Ni atoms in the electroplated Ni layer.

The Influence of Slide Burnishing on the Technological Quality of X2CrNiMo17-12-2 Steel.

Metal products for the metallurgical and machinery industries must meet high requirements in terms of their performance, including reliability, accuracy, durability and fatigue strength. It is also important that materials commonly used to manufacture such products must meet specific requirements. Therefore, various techniques and technologies for modifying the surface layer are becoming more and more widely used. These include burnishing, which may be dynamic or static. This article studies the process of slide burnishing of surfaces of cylindrical objects. The burnishing was performed using a slide burnisher with a rigid diamond-tipped clamp on a general-purpose lathe. The tests were performed for corrosion-resistant steel X2CrNiMo17-12-2. The aim of the research was to determine the impact of changes in burnishing conditions and parameters-feed rate, burnisher depth and burnishing force at a constant burnishing speed-on the surface roughness and hardness. Additionally, the microstructure was assessed in the critical areas: the surface and the core. Another phenomenon observed was surface cracking, which would be destructive due to the occurrence of indentation. In the paper, it was stated that the microstructure, or rather the grains, in the area of the surface layer was oriented in the direction of deformation. It was also observed that in the area of the surface layer, no cracks or other flaws were revealed. Therefore, slide burnishing not only reduces the surface roughness but hardens the surface layer of the burnished material.

New Certified Reference Material of Tungsten Concentrate for Developing Multielement Analysis Techniques

A new multielement certified reference material of tungsten concentrate (GSO 11541–2020) – wolframitehubnerite concentrate (hard-alloyed), KVG(T) was developed. Its metrological characteristics were established via results of interlaboratory experiment. The analytical results were obtained at the testing laboratories of 13 scientific and manufacturing organizations of Russia, Belarus, Kazakhstan, and Uzbekistan using single-element chemical analysis methods (gravimetric, spectrophotometry, atomic absorption spectrometry, etc.), as well as modern multielement methods (atomic emission spectrometry with arc discharge or inductively coupled plasma, inductively coupled plasma mass spectrometry, X-ray fluorescence spectrometry). The mass fraction values for ten elements certified; for eleven elements recommended; and for 39 elements, as well as hygroscopic and crystallization water, are given as information data. This CRM is intended for certification and validation of single and multielement methods, as well as quality assurance in analysis of the ores and products of their processing in mining, metallurgical, and chemical industries and in scientific research. The information potential of GSO 11541–2020 is higher than that of imported reference materials.

Enhancing point cloud data fusion through 2D thermal infrared camera and 2D lidar scanning

Sensor data fusion from multiple sources plays a pivotal role in advancing our understanding of real-world phenomena. This paper focuses on the integration of a thermal imager and a lidar to simultaneously capture four-dimensional (XYZT) space coordinates and temperatures. The fusion of data relies on establishing correspondence between overlapping lines in the lidar’s 3D point cloud and the infrared (IR) camera’s 2D thermal map. The presented combination method offers several key advantages. Firstly, it simplifies the calibration process. Furthermore, it can achieve near real-time performance, enabling prompt data analysis. Moreover, the method demonstrates high accuracy in capturing spatial information and temperature measurements. The thermal IR camera used in the experiment features a 1280 × 1024 pixel cooled indium antimonide (InSb) detector, operating in the short wavelength infrared (MWIR) spectral range of 1.5 to 5.5 µm. It provides temperature readings with ± 1 K accuracy and sub-30 mK resolution. On the other hand, the lidar system delivers centimeter-level precision within a range of approximately 1 to 12 m, even in well-lit outdoor environments. The experimental results validate the effectiveness of our combined system, successfully generating high-quality four-dimensional (4D) point clouds. The integration of the thermal IR camera and profilometer presents an intriguing tool with significant potential in various industrial applications. For instance, it can be employed to accurately assess gas leaks, enhance metallurgical processes, and improve safety on construction sites.

Copper Alloying Improves the Microbiologically Influenced Corrosion Resistance of Pipeline Steel

Microbiologically influenced corrosion (MIC) has long been a critical issue due to its potential to cause severe damage to equipment and the associated risk of operational failures, leading to significant financial losses. This study investigates the resistance to MIC caused by sulfate-reducing bacteria (SRB) in four types of pipeline steel materials, which are soon to be introduced to the market. Two of these materials have been alloyed with copper during the metallurgical process. The uniform corrosion rates of the copper-alloyed materials were found to be 0.012 ± 0.002 mm/y, 0.060 ± 0.01 mm/y, and 0.010 ± 0.001 mm/y under test conditions of 25 °C, 40 °C, and 60 °C, respectively. In contrast, the unalloyed steels exhibited corrosion rates of 0.370 ± 0.033 mm/y, 0.060 ± 0.01 mm/y, and 0.378 ± 0.032 mm/y, respectively. The data indicate that the copper-alloyed materials demonstrate superior resistance to MIC, as confirmed by corrosion morphology, weight loss measurements, and electrochemical data. These findings suggest that copper alloying can significantly enhance the MIC resistance of steel materials, offering a promising direction for future material development.

The road to carbon neutrality in the metallurgical industry: Hydrogen metallurgy processes represented by hydrogen-rich coke oven gas, short-process metallurgy of scrap and low-carbon policy

Abstract With the acceleration of global industrialization, the concentration of carbon dioxide is increasing in the atmosphere, and its negative impacts have seriously affected all walks of human life, so achieving carbon neutrality has become an urgent task for achieving sustainable development. As an important energy-intensive industry, the metallurgical industry occupies an important position in the global carbon-neutral agenda. In China, the metallurgical industry is actively researching and developing a new green metallurgical model of “replacing carbon with hydrogen”, exploring the feasibility of utilizing renewable energy sources to produce hydrogen from electrolysis to reduce iron ore, and at the same time utilizing hydrogen-rich coke oven gas to get rid of the over-reliance on coke; at the same time, the government’s policies provide support and incentives to elevate sustainable development and technological innovation in the metallurgical industry. support and incentives to elevate sustainable development and technological innovation in the metallurgical industry. Against this background, this paper describes the key initiatives taken by the metallurgical industry in the process of achieving carbon neutrality, including the metallurgy using hydrogen processes using hydrogen-rich coke oven gas as a source of reducing gas, short-process metallurgy of scrap, and technology that reduce emissions and save energy. Through case studies and policy analyses of new green metallurgy, this study demonstrates the potential and achievements of the metallurgical industry in achieving global carbon neutrality. It concludes with a call for the metallurgical industry to continue to strengthen innovation and work with governments and academia to pave the way toward carbon neutrality. Through new metallurgical technologies, improved energy and resource efficiency, and sustainable development, the metallurgical industry will make a significant contribution to the goal of global carbon neutrality.

Computational Fluid Dynamics Modeling of Multiphase Flows in a Side-Blown Furnace: Effects of Air Injection and Nozzle Submerged Depth

The side-blown smelting process is becoming popular in the modern metallurgical industry due to its large potential for dealing with complex materials. To further enhance its efficiency, it is essential to comprehensively understand the complex gas–liquid flow behavior in the smelting bath. In this study, the volume-of-fluid method is employed to establish computational fluid dynamics modeling on a 1:5 scaled model of a side-blown furnace. The simulation was validated against the experimental results. Notably, the influences of the nozzle’s submerged depth, injection velocity, and angle were systematically investigated. The results show that increasing the injection velocity from 29.44 to 58.88 m/s resulted in 52.97%, 116.67%, 500.00%, and 5.88% increases in the interface area, liquid velocity, liquid turbulent kinetic energy, and gas penetration depth, respectively. The maximum gas–liquid interface area, gas penetration depth, velocity, and turbulence of the liquid were found at an injection angle of 30°. Furthermore, increasing the submerged depth increased the interface area and the velocity of the liquid but decreased the turbulent kinetic energy of the liquid. Overall, increasing the injection velocity is considered a more effective measure to strengthen the smelting intensity.

Numerical study on the effect of high efficient cooling nozzles and varying cooling intensity on metallurgical transport behaviors during the slab continuous casting

In this study, the spray characteristics of the cooling water flux of the traditional single nozzle and novel dual nozzle were innovatively and effectively incorporated into a 3D/2D flow-temperature-concentration segmented model. The model was used to investigate the effects of spray characteristics on the flow, heat distribution, solute transport, solidified shell, and mushy zone of steel in the continuous casting. The results showed that various flow patterns of liquid steel in the turbulent zone significantly affected the temperature and carbon concentration distribution. Until Zone 7, the cooling water fluxes in the six cases remained unchanged. The peak temperatures of cases 1 and 4 in Zone 7 were 1253.11 and 1273.51 K, respectively, indicating that the spray characteristic was the primary cause of the variations in slab surface temperatures. The cooling water fluxes in the six cases change from Zone 8 onward. The six cases had differences of −21.39, 17.87, 46.95, −22.08, 16.86, and 45.68 K between the initial and final temperatures in Zone 8, respectively, meeting the requirement of keeping the maximum temperature recovery rate of slab surface under 100 °C/m. However, the final temperatures for cases 2, 3, and 6 were 1225.62, 1196.50, and 1218.91 K, respectively. These temperatures fall within a realistic plastic temperature range, which must be higher than 1220 K. As a result, the plastic cracking in the slab was possible. The maximum temperature gradient differences of the six cases between feature lines at the end of Zone 8 were 0.793, 0.814, 0.829, 0.185, 0.179, and 0.179 K/mm. These results showed that the optimization effect on the temperature gradient difference was insignificant as the cooling intensity rose. However, the carbon concentration uniformity was marginally improved by increasing the cooling water flux. Finally, a state-owned steel company in China chose case 5 (dual nozzle with moderate cooling intensity at the slab solidified end) as the optimum option for the slab continuous casting caster. The dual nozzle enhanced and promoted the efficient and homogeneous production of the metallurgical process.

A clean metallurgical process for vanadium precipitation from vanadium-rich solutions

Ammonium salt vanadium precipitation process has excellent performance in industrial production, but its shortcomings such as high cost and environmental impact are not conducive to sustainable development. In this paper, ethylenediamine was selected as the precipitant, and vanadate was precipitated from acidic simulated vanadium-rich solutions by the ammonium salt precipitation process. The high purity V2O5 product was obtained after calcination. Under optimal conditions, the precipitation rate of vanadium reached 94.8 %, and the purity of vanadium was as high as 99.1 %. The vanadium precipitation product was hexamethyl ammonium, and the vanadium product was V2O5. It can be derived by the differential method that the reaction order was n = 2.4, the reaction rate equation was CV-1.4=kt+a, and the apparent activation energy was 27.8097 kJ/mol, which can be classified as the diffusion-controlled reaction. This innovative process enables a savings of 5050 yuan per ton of V2O5. On this basis, a complete V2O5 production process with zero waste discharge was designed.

The effect of NaOH and KOH on the strength-mechanical properties of alkali-activated composites based on granulated blast-furnace slag

Abstract Alkali-activated systems are a more sustainable alternative to Portland cement concrete. The activation of latently hydraulic and pozzolanic raw materials in these composites is one of the many investigated factors, where the price ratio and the ability to optimally activate the mentioned precursors with the given activator play a major role. The subject of the presented work is a comparison of the influence of NaOH and KOH on the development of the strength-mechanical properties of alkali-activated materials based on granulated blast furnace slag - the secondary raw material of metallurgical processes.

ВАРИАНТ КОМПАКТИРОВАНИЯ МЕЛКОДИСПЕРСНЫХ ЖЕЛЕЗОСОДЕРЖАЩИХ МАТЕРИАЛОВ ДЛЯ МЕТАЛЛУРГИЧЕСКОГО ПЕРЕДЕЛА

The paper presents the results of a study of options for compacting fine iron-containing materials for metallurgical processing. The authors have proposed a method that involves the use of, in addition to an iron-containing material, a thermoplastic binder material. In this case, aggregation of the mixture and strengthening of the resulting aggregates is carried out simultaneously in a closed mold under the influence of pressure and temperature not lower than the softening temperature of the thermoplastic material. It is possible to obtain a compact unit, convenient for storage and transportation, that successfully performs the functions of a charge component during cupola and blast furnace melting of cast iron.

RISKS OF INJURY AND HEALTH DAMAGE WHEN USING BLACKSMITH EQUIPMENT

The article identifies the need to analyze the risks of injury and health damage when using blacksmith equipment which is due to the implementation of the latest technologies for the successful economic development of the country, the introduction of a risk-oriented approach, as well as the implementation of international standards in all sectors of the economy. It was noted that international standards are based on the use of a risk-oriented approach in solving issues of safety and occupational health of employees. Therefore, this requires the implementation of new approaches and the formation of new relationships in particularly dangerous areas of production. The general state of occupational injuries and deaths of workers in Ukraine for the period starting from 2022 to 2024 (four months of the current year) is given. The given data indicate an increase in the number of accidents at work which is further complicated by the war. These data indicate an increase in injuries at work which is a bad indicator and the need to implement modern risk-oriented technologies in the metallurgical industry. Analyzing the situation in the metallurgical industry where blacksmith equipment is widely used it should be noted that the main causes of injury and death of workers are organizational. This proves that the risk management system at enterprises is imperfect and needs to be improved and brought into line with international standards. Scientific approaches to determining the risks of injury and damage to the health of workers (operators) when using blacksmith equipment are considered. It is shown that modern technologies of metal processing by forging as one of the methods of pressure processing, use more and more robotic complexes which have risks associated with the organization of work in the conditions of the probability of physical impact of their individual elements and substances on workers. The dangerous and harmful factors that accompany the work of operators when using the MKP10 forging manipulator are given. The operation of the MKP10 manipulator is considered as an example. Tables and diagrams of the manipulator are made in accordance with the DSTU ISO 12100:2016 standard. The calculation of the risk indicator of the MKP10 manipulator was also performed which showed that the risk is average in terms of its damage and probability indicators. This leads to the need to apply risk management to control such risk and reduce it to acceptably small values.

Оцінка клініко-функціональних показників ризику розвитку пневмоконіозу в поєднанні з хронічним обструктивним захворюванням легень у працівників гірничорудної та металургійної промисловості

Оцінка клініко-функціональних показників ризику розвитку пневмоконіозу в поєднанні з хронічним обструктивним захворюванням легень у працівників гірничорудної та металургійної промисловості

Cost Analysis of the Recent Projects for Overseas Vanadium Metallurgical Processing Plants

Cost Analysis of the Recent Projects for Overseas Vanadium Metallurgical Processing Plants

Utilisation of titanium-containing wastes in the cement industry: A literature review

The metallurgical industry is among the leaders in waste production which has a high potential for recycling. The review paper considers the problems of metallurgical industry waste management and some possible ways of their solution. Waste acidic pickling solutions of titanium (titanium sludge) can be used as an additive to cement clinkers both to improve the characteristics of building materials and the efficiency of their production process. The influence of calcium fluoride (CaF2) and titanium dioxide (TiO2) on cement clinkers at different concentrations of substances and sintering temperatures has been reviewed. The data on changes in the content of free lime (f-CaO), patterns of formation and distribution of clinker phases: alite, belite, celite and calcium aluminiferite have been presented. Mechanisms of CaF2 and TiO2 inclusion in the composition of various cement phases have been explained. The conclusion has been made that the application of titanium-containing wastes allows not only to recycle them, but also to obtain construction materials with improved characteristics.

Development of a mechanism for managing the level of investment in R&D of city-forming enterprises (by the example of the metallurgical industry)

The object of the study is investment in R&D of enterprises. The problem of developing a mechanism for managing the level of R&D investment at industrial enterprises has been solved. The results are obtained: – gradation of R&D investment levels at enterprises based on the application of the beta coefficient calculation methodology adapted to the R&D sphere; – distribution of city-forming enterprises of the metallurgical industry by R&D investment levels: high level – 27 % of surveyed enterprises, average – 18 %, low – 55 %, critical – 0 %; – development of a matrix based on the comparison of the level of R&D investment and the level of sales volumes of the enterprise's products calculated according to one algorithm. For each cell of the matrix, management decisions of strategic nature are proposed to increase the level of R&D investment. The results obtained are explained by the assumption of a linear relationship between the size of R&D investment of a particular enterprise over time and aggregate industry R&D investment (as a benchmark). The tendency of R&D investment growth in the industry, regularity of R&D investments of the surveyed enterprises were confirmed, time series of R&D investment both at the evaluated enterprise and in the industry as a whole were processed using trend smoothing. The features of the obtained results lie in the application of comparable coefficients (investments in R&D), as well as in the application of the developed assessment in the management of the enterprise. The practical significance of this study results is the possibility of applying the obtained conclusions and recommendations to increase the level of R&D investment of large industrial enterprises in the volume, scope and conditions corresponding to the developing economy

Analysis of the international competitiveness of domestic metallurgical enterprises

Introduction. The relevance of the research topic is determined by the globalization trends of economic development, the growing competitive activity of enterprises, the increase in competitive tension in world markets, the formation of specific forms of competition. The purpose of the paper is to determine and structure the factors of international competitiveness of domestic metallurgical enterprises at the mega-, macro-, meso- and micro-levels, to identify the most priority positions for winning and maintaining the market. Results. Based on the analysis of the dynamics of metal products production during 2021-2023, the current state of operation of the largest metallurgical enterprises, the dynamics of foreign investments in the metallurgical industry of Ukraine, the main reasons for the deterioration of the competitive positions of the domestic MMC on the international market of metal products are determined. The negative and positive factors that determine the international competitiveness of MMC of Ukraine at the mega-, macro-, meso- and micro-levels are analyzed. The result of the analysis is the conclusion regarding the absolute predominance of the influence of external factors in the conditions of full-scale military aggression of the Russian Federation, the significant dependence of the development of MMC of Ukraine on the state of world markets. And vice versa, domestic metallurgy has an inverse effect on the global production of metal products, because it has significant resource, production and scientific potential. Considering the specifics of metallurgical enterprises, the state of the world economy and globalization processes, the factors of competitiveness of metallurgical enterprises are structured according to the degree of susceptibility to changes in the conditions of globalization (flexible, difficult to change) and according to the degree of influence on the level of global competitiveness (moderate influence, significant impact). Conclusions. The analysis of the factors of international competitiveness of the domestic metallurgy showed that in the conditions of its sharp decline, the priority for the industry is not to lose its own competitive advantages, including through the search and effective use of positive factors of international competitiveness. At the same time, the basis of increasing the international competitiveness of the metallurgical industry is to increase the competitiveness of domestic metallurgical enterprises both on the domestic and international markets. It has been proven that when developing a strategy for increasing international competitiveness, it is appropriate to determine the result of focusing on the factors of a more intensive manifestation of the classification feature, that is, on flexible factors of significant influence.

Temperature‐dependent viscosity effects on heat transfer characteristics of grade three fluid in electromagnetohydrodynamic flow between large parallel plates maintained at uniform temperatures

AbstractHeat transfer characteristics in the electromagnetohydrodynamic flow of a third‐grade fluid between parallel plates have already been examined by researchers, but studies on the effect of temperature‐dependent viscosity on velocity, temperature, and heat transfer coefficients are very few. The present study investigates the heat transfer behavior of a third‐grade fluid flow between large parallel plates, taking temperature‐dependent viscosity when magnetic and electric fields are imposed externally. The plate walls are subjected to uniform temperatures. Consideration of temperature‐dependent viscosity results in the formulation of the phenomenon by nonlinear, coupled differential equations, which are solved by applying the least‐square method (LSM). Solving coupled, nonlinear equations by the LSM requires a great deal of modification in the implementation process. The obtained results in terms of dimensionless velocity are validated with the results of earlier studies and are also in a close match with the results of the Adomian decomposition method of the current study. Results indicate that for a higher value of the viscosity parameter, at first, velocity increases with an increase in the non‐Newtonian parameter. Beyond a certain value of the non‐Newtonian parameter, velocity starts reducing. Temperature, at all points of any cross‐section, increases up to a certain non‐Newtonian parameter and then reduces with the rise in the same parameter. For higher values of the viscosity parameter and low non‐Newtonian parameters, the upper plate requires an enhanced rate of cooling. Whereas, for higher values of the non‐Newtonian parameter at higher viscosity parameters, a lower heating rate is required. The results of the mathematical model can serve to be useful in the field of liquid metal flows in metallurgical industry, micropumps, medical and biological sectors, and microelectromechanical applications.