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A system was designed to detect possible violations of the operating rules of the enterprise without changing the behavior of the entire system as a whole, as well as to automatically start the assembly of the simulated behavior of a real application using unit and functional testing technologies. In the work, an analysis was made of the subject area of the work process of drivers, managers and operators. It was found that the time to find possible violations exceeds the permissible value. The audit department engaged in verification had problems with the quick unloading of potential violators. The department made unloading and manual search, which led to a longer identification of violations both from the side of drivers and managers. It is possible to solve this problem and increase the efficiency of the process by developing an automatic analysis system. An analysis of the management process was carried out. Based on the analysis, a model of system use cases was developed, from which user and functional requirements were defined and formed. A functional model of the system was introduced. The basic algorithms are described. Connections between system entities were revealed, analysis classes and detailed UML diagrams were compiled. Thus, when performing the work, all the features and nuances of the design of information systems were taken into account, then according to the presented models, you can develop an information system and implement it in various organizational structures.

During contact flash welding of rails, the metal is heated and continuously cooled in the zone of thermal influence. Accelerated heating and subsequent intensive cooling, implemented by the pulsed flashing-off method, lead to the formation of quenching structures. Subsequently, during the operation of the rails welded joint, this leads to the formation of cracks and to brittle destruction. We have investigated the possibilities of using contact heating after welding to avoid the formation of quenching structures in the metal of the welded joint made of R350LHT rail steel. The thermal cycles during welding and subsequent contact heating were recorded. The regularity of formation of the weld metal structure was established including the zone of thermal influence during pulsed contact heating for R350LHT rail steel. It is shown that contact pulse heating slows down the welded joint cooling and prevents the formation of quenching structures. However, contact pulse heating when using suboptimal modes can also lead to the opposite effect. It is determined that with a significant investment of heat by contact heating, cooling rate of the metal exceeds the critical one, transformation process passes through a diffusion-free mechanism with the formation of martensite coarse-grained structure. The use of thermokinetic and isothermal diagrams of austenite decomposition at known thermal welding cycles allows us to significantly narrow the search limits for optimal modes of contact butt welding of railway rails and subsequent contact heating. The use of optimal contact heating modes makes it possible to obtain a minimum length of heat-affected zones with reduced hardness without the formation of quenching structures in the welded joint of railway rails.

A two-level control system for the temperature mode of smelting, out-of-furnace processing and preparation for casting of low-carbon steel G/ET is proposed in the conditions of BOF shop-2 of JSC “United West Siberian Metallurgical Combine”. Depending on the technological scheme, it is possible to design various control systems for the steelmaking complex with sequential, parallel and combined inclusion of individual operations and processes. The control system of a sequential group of objects is considered on the example of steel G/ET. The control system includes an external control loop that allows coordinated control of the shop departments by optimizing the mode of technological process conducting at the facility, taking into account the actual operation performed at the previous facility. The implemented nonparametric algorithm of dual control allows the decision-maker to perform joint operational adjustment of control actions for local control loops. The temperature mode of the melts of low-carbon steel G/ET is analyzed and it is revealed that the processing time of the steel ladle at each stage of the BOF – CCM technological route has a significant impact on the steel temperature mode. In accordance with this, the criteria for temperature control quality are formed. The results of computational experiment showed that the introduction of a control unit with a decision-maker contributes to the rational control of metal temperature mode in the BOF – CCM site, and as a result, obtaining a given chemical composition and temperature of steel within narrower limits. It allows one to eliminate deviations from the contact schedule of the main units, and to increase the number of melts in the series and the rate of continuous casting.

Tribotechnical tests and microstructural studies were carried out. Wear mechanism of nanostructured metalpolymer self-lubricating composite materials has been established. This mechanism involves in the formation of separating polymer layers on the friction surface, which reduces the coefficient of friction and running-in period of parts of friction units. Carbon nanoparticles move along the friction surface, hinder the development of seizure processes during the interaction of microroughnesses of the contacting surfaces of the material and the counterbody during the destruction of the separating polymer layers. It was found that the polymer filler is displaced from the friction zone, carbon nanoparticles are pressed into the open areas of the surface of the copper matrix of the composite when the pressure in the tribocontact is higher than 1.5 MPa. The temperature in the tribocontact increases, the polymer filler degrades, the carbon nanoparticles are removed from the friction zone, the strength properties of the composite decrease, the friction coefficient and the wear rate increase at a sliding speed above 1.5 m/s. The obtained research results can be used in mechanical engineering, transportation industry and power engineering.

Due to the complex composition and high proportion of alloys in traditional ultrahigh strength steel, the dilemma caused by ultrahigh strength and low toughness in casting and forging processes requiring subsequent heat treatment can be mitigated with an efficient and economical rolling process. In this work, the effect of deformation parameters on dynamic recrystallization (DRX) and dynamic recovery (DRV) is discussed through stress-strain analysis, the DRV mathematical model is obtained, and then the dynamic recrystallization activation energy, Zener–Hollomon equation, and hot working equation are obtained. The critical strain of DRX detected by the P-J method is ε c / ε p = 0.631 , which indicates that dynamic recrystallization of this novel steel is relatively easy to achieve by the rolling process. These models and conclusions have potential to be generalized for the formulation of process specification and process configuration without requiring extensive material testing.

Spent electroplating solutions contain small amounts of Pd(II). Cementation of Pd(II) with zinc metal powder is practiced to concentrate the Pd. Dissolution of the cemented Pd metal is necessary to recover pure Pd metal or compounds. In this work, the leaching behavior of Pd metal in inorganic acid solutions (hydrochloric and sulfuric acid) in the presence of an oxidizing agent such as H2O2, NaClO3, or NaClO was investigated. To determine the optimum conditions for Pd leaching, experiments were conducted by adjusting the concentration of the acids and oxidizing agents, reaction temperature and time, and pulp density. Complete leaching of Pd was possible using a hydrochloric acid solution with 3 kinds of oxidizing agents, whereas only NaClO was effective in the leaching with sulfuric acid solution. The chloride ions of HCl and NaClO3/NaClO play an important role in enhancing the leaching of Pd, due to the formation of Pd chlorocomplexes and by decreasing the reduction potential of Pd(II). Compared to H2O2, NaClO3 and NaClO showed some merits as oxidizing agents in terms of reaction time, temperature and low acid concentration. Based on the optimum leaching conditions of single Pd metal, the conditions for the complete leaching of Pd and Zn from the metallic mixtures were obtained.

Separation of ultrafine hematite from quartz and kaolinite gangue minerals using selective flocculation technique is markedly affected by the state of inter mineral interaction which is governed by type and content of polyvalent metal ions. Because of the presence of polyvalent metal ions hetracoagulation of gangue minerals is widely acknowledged, thus selective flocculation of ultrafine hematite from associated gangue minerals is challenging task when their concentration is above 10 ppm. This study has shown that state of strong interaction of gangue minerals with hematite due to presence of 15 ppm Ca2+, 3 ppm Mg2+ and 3 ppm Fe3+ ions can be weakened by addition of optimal dose of Sodium Hexametaphosphate (SHMP) ligand. The optimization of ligand dose is achieved through analysis of Zeta Potential (ZP) as a function of slurry pH. It is noted that 50 ppm of SHMP is sufficient to restore the ZP of hematite, where selective dispersion of the slurry constituents are possible. Our results further showed that conventional strategy of obtaining minimum difference of ±30 mV in the ZP of hematite and gangue minerals quartz and kaolinite would not work especially in the presence of 15 ppm Ca2+, 3 ppm Mg2+ and 3 ppm Fe3+ ions. Attempts to achieve the minimum threshold difference in the ZP of the minerals will cause over dispersion.

The hot cracking susceptibility in the Trans-Varestraint test was evaluated using the nominal strain calculated using the curvature radius of a bending block and the thickness of a specimen based on the theory of material mechanics. The nominal strain was calculated using the material properties at room temperature. Thus, in the Trans-Varestraint test, the non-uniformity of the strain around the weld part due to the temperature distribution is not considered. Therefore, the strain in the Trans-Varestraint test cannot be evaluated correctly. The aim of this study is to reveal the loaded strain at the weld metal to understand the evaluation of hot cracking susceptibility in the Trans-Varestraint test. The loaded strain around the trailing edge of the weld pool of pure iron was measured in-situ using a high-speed camera and high-resolution optical lens. The results of strains measured using image analysis and the finite-element method at the center of the weld bead were compared. Accordingly, it was clarified that the strain was concentrated on the weld part owing to the bending occurring along the weld line, and the strain exceeding the nominal strain was loaded to the trailing edge of the weld pool.

Alloy 825 is a nickel-based alloy that is commonly used in applications where both high strength and corrosion resistance are required, such as tanks in the chemical, food and petrochemical industries and oil and gas pipelines. Components made from Alloy 825 are often manufactured using hot deformation. However, there is no systematic study to optimise the processing conditions reported in literature. In this study, a processing map for as-cast Alloy 825 is established to maximise the power dissipation efficiency of hot deformation in the temperature range of 950 to 1250 °C at an interval of 50 °C and strain rate range of $$0.01\, {\text{s}}^{ - 1}$$ 0.01 s - 1 to $$10.0\, {\text{s}}^{ - 1}$$ 10.0 s - 1 to a true strain of $$0.7$$ 0.7 using a Gleeble-3500 thermomechanical simulator. The processing conditions are also correlated to the Vickers hardness of the final material, which is also characterised using optical microscopy and scanning electron microscopy, including electron backscattered diffraction. The true stress-true strain curves exhibit peak stresses followed by softening due to occurrence of dynamic recrystallization. The activation energy for plastic flow in the temperature range tested is approximately $$450\,{\text{ kJ mol}}^{ - 1}$$ 450 kJ mol - 1 , and the value of the stress exponent in the (hyperbolic sine-based) constitutive equation, $$n = 5.0$$ n = 5.0 , suggests that the rate-limiting mechanism of deformation is dislocation climb. Increasing deformation temperature led to a lower Vickers hardness in the deformed material, due to increased dynamic recrystallization. Raising the strain rate led to an increase in Vickers hardness in the deformed material due to increased work hardening. The maximum power dissipation efficiency is over $$35\%$$ 35 % , obtained for deformation in the temperature range 1100-1250 °C and a strain rate of $$0.01\, {\text{s}}^{ - 1}$$ 0.01 s - 1 -$$0.1\, {\text{s}}^{ - 1}$$ 0.1 s - 1 . These are the optimum conditions for hot working.

This study aims to evaluate the weldability of dissimilar welds with the Inconel 625 and the Hastelloy C-276 nickel-based alloys deposited on ASTM A36 and AISI 1045 carbon steel plates. The welds were carried out by the GMAW process and evaluated by the Trans-Varestraint test. The test results were statistically evaluated, and Fusion Zone solidification processes were simulated in JMatPro software using several dilution levels. The analysis of variance (ANOVA) test results showed that the two different base metals did not affect the weldability of Inconel 625. However, the Hastelloy C-276 alloy showed a significant drop in weldability with the AISI 1045 steel compared to the ASTM A36. The results of the Hastelloy C-276 as the filler metal and the AISI 1045 steel as the base metal showed greater susceptibility to solidification cracking than all the other pairs tested, according to the Trans-Varestraint test. Moreover, the ANOVA test results indicated that the different heat input levels did not influence the sets’ weldability; this was probably because there was only a tiny variation in the dilution levels. The solidification process simulation indicates that higher dilution levels promote the precipitation of a larger secondary phase fraction.

A novel magnesium (Mg) production process utilizing an electrolytic method was investigated for the direct reduction of magnesium oxide (MgO). Electrolysis of MgO was carried out with an applied voltage of 3.0 V using a copper (Cu), silver (Ag), or tin (Sn) cathode and carbon (C) or platinum (Pt) anode in magnesium fluoride (MgF2)−calcium fluoride (CaF2)−sodium fluoride (NaF) at 1273 K or MgF2− lithium fluoride (LiF) at 1083−1093 K. After the electrolysis of MgO in MgF2−CaF2−NaF molten salt, Mg alloys such as Mg2Cu, Cu2Mg, or Mg2Sn phases were produced with current efficiencies of 75.8−85.6% when the concentration of Mg in Mg alloys was 9.1−14.6 mass%. In addition, when the electrolysis of MgO was conducted in MgF2–LiF molten salt, Mg alloys such as Mg2Cu or AgMg phase were produced with current efficiencies of 76.2−81.7% when the concentration of Mg in the Mg alloys was 12.5−13.2 mass%. In addition, to produce high-purity Mg metal from Mg alloys, vacuum distillation was conducted. When vacuum distillation was conducted at 1100−1400 K for a duration of 5 h, the concentration of Mg in the Mg alloys feed decreased from 30.2−34.1 mass% to 0.64−1.75 mass%, and Mg metal with a purity of 99.998−99.999% was obtained under certain conditions. Therefore, the molten salt electrolysis using liquid metal cathode (MSE-LMC) process developed here is feasible for the direct reduction of MgO using an effective and environmentally sound method.

An isothermal diagram of decomposition of supercooled austenite of R350LHT steel was constructed based on the results of dilatometric, metallographic and hardness analysis of this decomposition during continuous cooling and under isothermal conditions. When comparing the thermokinetic and isothermal diagrams, it was found that the thermokinetic diagram plotted during continuous cooling shifts downward and to the right in comparison with the isothermal diagram. This result is fully consistent with the known regularities. During the research, the critical points of R350LHT steel were determined: Ас1 = 711 °С; Мn = 196 °С. This isothermal diagram was used to determine the temperature of the minimum stability of overcooled austenite, which was 500 °C. Under isothermal conditions, pearlite-type structures appear in the temperature range from 700 to 600 °C. At 550 °C, a mixture of pearlitic and bainitic structures is formed. In the temperature range from 500 to 250 °C, bainitic structures are formed: at 500 – 400 °C – upper bainite; at 350 ° C – a mixture of upper and lower bainite; at 300 – 250 °С – lower bainite. Almost in the entire studied temperature range of overcooled austenite isothermal decomposition, an increase in the hardness of the transformation products is observed with a decrease in the holding temperature from 246 HV (at 700 °C) to 689 HV (at 250 °C). However, at a temperature of 500 °C, a slight drop in hardness occurs, which is apparently caused by the appearance of retained austenite during the development of bainitic transformation.

The process of enrichment of potash ore using industrial oils as a hydrophobizing agent in the collective mixture of potassium chloride, which is a composition of salts of higher aliphatic amines, pine oil and polyethylene glycol PEG- 400, has been investigated. A comparative analysis of the influence of industrial oils I-8A, I-12A, I-30A and liquid paraffins on the technological parameters of potash ore flotation has been carried out. The influence of hydrophobizing additives on the adsorption of amine on potassium chloride crystals was investigated by infrared spectroscopy. It has been established that the introduction of industrial oils into the flotation system ensures the recovery of potassium chloride at the same level as when using a collective mixture with liquid paraffins. The best flotation performance when using industrial oils is possible by increasing the consumption of the apolar reagent.

Change is constant, as nothing stays the same. Consider the words of the Chinese philosopher Lao Tzu, “Life is a series of natural and spontaneous changes. Don't resist them—that only creates sorrow. Let reality be reality. Let things flow naturally forward in whatever way they like.” Some changes are the result of biology and the passage of time, within the natural cycle or order of things. Others are self-generated, under our own control and resulting from willful efforts, or dependent upon encounters with significant others—family, friends, colleagues, and others close to us. Still, other changes occur because of circumstance or fate, a proverbial "date with destiny" and often beyond what we feel is our control. Whether it is our personal life or occupational, like metalcasting, this change can facilitate transition and transformation. I have coined the term metalmorphasis and this lecture as reflection of how to embrace change, recognize the opportunities presented and utilize it as a vehicle for new beginnings. This is not just philosophical but also a look how we as metallurgist and metalcasters apply and control input variables (time, temperature, pressure, chemical reactions, etc.) to transform metals and create metalmorphasis.

The article deals with the problems arising during the mechanical and thermal treatment of the TMZ-450D diesel engine cylinder, which is the base part of the engines of small-sized generators and compressors, which are widely used for mobile units in the oil and gas and mining industries. It was found that the metal in the casting has a non-uniform structure, the density of which ranges from 6.75 to 7.25 g/cm3. Redistribution of dislocations and residual stresses in the casting leads to significant changes in the size and shape of the main bore. In addition to the successive changes in size specified by the technology due to the removal of the designated allowance, the dimensions and shape change arbitrarily, uncontrollably in the course of the technological process. It is shown that artificial aging by a thermal method does not provide the desired dimensional stability; therefore, it is proposed to supplement it with natural aging after rough boring for six months. It was revealed that the use of morally and physically outdated equipment makes it necessary to increase the number of finishing operations of honing and, accordingly, to increase the labor intensity of cylinder manufacturing. The use of a two-position boring machine is substantiated, on which the transitions of semi-finishing and fine boring are combined. This completely eliminates the copying of errors that arose when changing the base on previous operations. The use of a two-position modular boring machine ARS-4/Ts of increased accuracy and rigidity significantly increases the accuracy of the bore hole, which makes it possible to reduce the number of honing operations. A variant of the technological process of mechanical and heat treatment is proposed, including natural aging, the use of double boring on a modular boring machine, which will reduce the number of honing operations to one, including rough and finish transitions.

The aim was to investigate the chemical composition of refinery slag obtained during silicon production in order to identify approaches to its further recycling. Research samples were collected from the slag remained after oxidation refining at the JSC Silicon (AO Kremny), RUSAL (Shelekhov, Irkutsk Oblast). The methods of X-ray phase, X-ray fluorescence, metallographic and scanning electron microscopy were employed to investigate the chemical composition of the samples. It was found that the refinery slag under study includes such basic components as elemental silicon, its carbide and oxide, as well as elemental carbon. It was shown that silicon carbide is the product of incomplete reduction, resulting from melting silica-containing ores in a smelting furnace. According to the conducted X-ray fluorescent analysis, the samples also contain (wt %): Ca - 7.40; Al - 3.80; Fe - 0.30; Ba - 0.19; K - 0.14; Na - 0.09; Sr - 0.09; Mg - 0.08; Ti - 0.05; S - 0.02. Calcium and aluminium are present in the slag mostly in the form of oxides. Complex oxides of an anor-thite type were also found: CaO Al2O3 2SiO2. The refinery slag under study also features insignificant amounts of other metal oxides, which are released from the furnace slag forming during the smelting process. The slag produced by oxidation refining during crystalline silicon production is a technogenic raw material containing valuable components. Due to the significant content of silicon in the refinery slag (from 42% to 65%), the existing methods applied to recycle such an industrial material were analysed in terms of additional silicon extraction or production of commercial silicon-containing products, which are in demand in various industries.

This work explains the application of plasticized cellulose triacetate (CTA) membranes with Cyanex 272 di(2,4,4-(trimethylpentyl)phosphinic acid) and Cyanex 301 (di(2,4,4-trimethylpentyl)dithiophosphinic acid) as the ion carriers of lanthanum(III) and cerium(III). CTA is used as a support for the preparation of polymer inclusion membrane (PIM). This membrane separates the aqueous source phase containing metal ions and the receiving phase. 1M H2SO4 is applied as the receiving phase in this process. The separation properties of the plasticized membranes with Cyanex 272 and Cyanex 301 are compared. The results show that the transport of cerium(III) through PIM with Cyanex 272 is more efficient and selective than lanthanum(III).

The results of investigations of the features of the behavior of the components of mixtures of refractory carbide powders with metals during explosive pressing are presented. It is shown that the main factor determining the compaction of mixtures is the dynamic flow of one of the phase components of the mixture into the initial pores of the powder. As the phase component of the mixture, the movement of which limits the degree of compaction and leads to the formation of a continuous matrix in the structure of the material pressed by the explosion, both the metal binder and the carbide component of the material can act.

The results of a study of the wear resistance of coatings based on cuprides of titaniumin the temperature range of 20-600 С are presented. It is shown that the wear resistance of nickel-doped coatings exceeds the wear resistance of binary coatings. With an increase in the Ni content of more than 10 %, their resistance to wear increases slightly.

Specific heat capacity (Cp), density (ρ), and thermal conductivity (λ) of phenolic-bonded 3D-printed sand (3DPS) molds have been determined in the temperature range of 20–1400 °C using differential scanning calorimeter (DSC), dilatometer, and hot wire method. The results have been used to simulate the thermal gradient in a sand mold during casting aluminum using a commercial simulation software. The simulated results have been compared with laboratory-measured results and simulated results using the software’s database for conventional mold making. Our results show that available database for sand thermal properties cannot explain the thermal gradient in 3DPS molds and this manufacturing process affects the thermal properties of the mold compared to traditional mold making. It is necessary to collect data for a variety of 3D-printed sand molds to ensure accurate modeling simulation in the foundry industry.

The article presents the study of the nature of dust and smoke generation during gas-oxygen blasting of a converter bath. The main reasons causing metal waste have been determined. Influence of the process main parameters on metal loss has been studied during dust removal and evaporation of iron in the reaction zone. The authors have estimated the process of metal pulverization due to CO bubbles floating, determined by the rate of their rise to the bath surface. Specifics of temperature regime of the reaction zone and heat balance have been determined when adding fuel to the oxygen flow. Adding fuel to oxygen makes it possible to increase heat input into the bath, while reducing the rate of decarburization. This enables reduction of dust discharge during rupture and crush of metal films by gas bubbles. The effect of combustion products oxygen use on metal impurities oxidation is considered. By the example of blasting carbon and alloyed steel for mill rolls, it has been shown that the degrees of CO2 and H2O decomposition in the bath are the main qualities of gas-oxygen blasting. These indicators determine the oxidizing and heating properties of the blast. Assessment of change in total, consumed heat and its losses with exhaust gases, depending on degree of the oxygen flow dilution with natural gas (methane), has been carried out. Under these conditions, use of submersible combustion torches with change in their oxidizing ability makes it possible to solve various technological tasks, including provision of an effective way to reduce dust emission in converter process.

In this manuscript, the latest developments pertaining to sensitization are discussed. Sensitization leads to intergranular corrosion and intergranular stress corrosion cracking. The advantages and disadvantages of conventional methods to combat sensitization are elaborated. Emerging/newer techniques such as grain boundary engineering, creation of orientation gradients, and high density of twinning to improve resistance to sensitization are also covered. Detection and monitoring of deleterious phase precipitation such as carbides, nitrides, and other intermetallic phases during operation necessitate making use of nondestructive testing (NDT) methods. Possible information that we get from NDT is for material characterization includes the size, shape, and location of a defect. Herein, the significant developments for monitoring and detection of phases concerning sensitization by NDT are discussed. These range from magnetic methods to ultrasonic techniques. The multi-physics approach is essential to fully utilize NDT to ensure/predict the lifetime of the components used in the industry. Further, proper selection of suitable NDT for defect detection can avert accidents, catastrophic failures, and economic losses due to corrosion degradation. For this, the corrosion engineer/corrosionist properly apply the suitable techniques (prevention, monitoring, and assessment) to address the issues of sensitization among the wide choice available.

In this article, we review existing approaches to recycling technogenic raw materials (ore dumps, metallurgical production slag, mill tailings of ore-dressing plants, etc.), containing non-ferrous and noble metals, which are accumulated in almost non-ferrous metallurgy industries. An analysis of existing technologies for processing technogenic raw materials (pyrite cinders and flotation tailings of concentration plants), which include enrichment, pyro- and hydrometallurgical and combined ways of extracting valuable components, was conducted on the basis of a review of published sources. It was shown that enrichment (screening, desliming in a hydrocyclone, enrichment using a concentration table, magneticliquid separation, flotation), pyrometallurgical and combined ways for extracting noble metals from this type of raw materials are unprofitable. The most satisfactory results were obtained using hydrometallurgical methods to extract valuable components from technogenic raw materials. Various solvents, such as sodium cyanide, thiocarbamide, sodium thiosulphate and sodium sulphite were tested as leaching agents. Cyanation proved to be the most effective way to extract noble metals from technogenic raw materials; however, this process is characterised by a high consumption of sodium cyanide. Therefore, it is of importance to discover an approach to extracting valuable components from such problematic products in order to make their processing more cost-effective by reducing cyanide consumption while maintaining gold extraction. According to the obtained results, gold-containing raw materials are promising in terms of extraction of nonferrous and noble metals using hydrometallurgical technologies. Future research should identify rational methods for processing technogenic gold-containing raw materials in order to make the technology more profitable for extracting valuable components.

The joining of plastics is required because component geometries are severely restricted in conventional manufacturing processes such as injection molding or extrusion. In addition to established processes such as hot plate welding, infrared welding, or vibration welding, hot gas butt welding is becoming more and more important industrially due to its advantages. The main benefits are the contactless heating process, the suitability for glass fiber reinforced, and high-temperature plastics as well as complex component geometries. However, various degradation phenomena can occur during the heating process used for economic reasons, due to the presence of oxygen in the air and to the high gas temperatures. In addition, the current patent situation suggests that welding with an oxidizing gas is not permissible depending on the material. On the other hand, however, there is experience from extrusion welding, with which long-term resistant weld seams can be produced using air. Investigations have shown that the same weld seam properties can be achieved with polypropylene using either air or nitrogen as the process gas. Experimental investigations have now been carried out on the suitability of different gases with regard to the weld seam quality when welding polyamides, which are generally regarded as more prone to oxidation. The results show that weld strengths are higher when nitrogen is used as process gas. However, equal weld strengths can be achieved with air and nitrogen when the material contains heat stabilizers.

At the Navoi Mining and Metallurgical Combine, which uses a large number of machine parts for mining operations, the issue of optimizing the compositions of wear-resistant chromium cast irons while maintaining their operational characteristics has arisen. The paper presents the results of studying the phase composition of the cast alloy, as well as the effect of heat treatment of cast iron with a high chromium content on its structure and properties. As heat treatment operations, quenching in various modes and low tempering were used. The study made it possible to systematize the known literature data on the heat treatment parameters of a group of wear-resistant chromium cast irons, as well as to optimize their heat treatment modes for parts operating in mining and processing industry.

One of the effective methods for studying any process is its physical modeling, during which it is possible to verify the concepts and hypothesis obtained previously by theoretical modeling. In the laboratory of metal forming of NUST “MISIS” there is ERW mill 30 – 50 for the production and simulation of processes for the continuous forming of longitudinal welded pipes of small and medium diameter, their welding and calibration. This article discusses the deformation zone of a pipe billet, using the first two stands of a molding mill as an example with a calibration of a roll tool for a pipe diam. 50×1.5 mm. Based on the analysis of methods for calculating the parameters of real roll calibers, a model of contact interaction of the pipe billet with the first and second roll open stands was developed and areas of the deformation zone were determined including their sizes: non-intensive and intense impact; input and output contact zones; springing up. Analyzing the conditions of contact interaction of the pipe billet with roll calibers, parameters of the pipe billet in contact with the first-caliber rolls were determined in seven sections, taking into account the features of continuous forming. An analysis of the results has shown that the maximum longitudinal deformation occurred at the edge of the billet in section B – B and was equal to 1.04 %, and for the pipe billet bottom it was 0.92 %. For the experiment, a grid was applied to the pipe billet using a laser engraver. During forming, the trajectory deviation of the pipe billet bottom from horizontal axis was recorded, and sizes of the forming sections were determined. Comparison of theoretical and experimental values has shown that the discrepancy between them does not exceed 7 %.

The paper describes an extensive study of features peculiar to physical and mechanical processes occurring in metal in the deformation zone during the continuous extrusion of Cu-ETP rectangular busbars 10×60 mm in size. Finite element computer simulation was used to obtain the values of extrusion power parameters. It was noted that moment and force values increase to the point of filling the press chamber free space with metal reaching a maximum of 12.26 kN·m and 1.54 MN, respectively. The stress-strain state analysis of metal in the deformation zone made it possible to obtain distribution fields of accumulated plastic strain, strain rate intensity and average stresses, and to build the graph of metal temperature variation over time during extrusion. Maximum levels of accumulated plastic strain and compressive stresses are observed in the contact zone of the workpiece with the press container abutment. The most intense metal deformation heating also occurs there. The comparison of modeling and microstructural study results indicate that a significant portion of the cast structure grinding work occurs at the entrance to the deformation zone and at the abutment zone subjected to the highest level of compression stresses. Metal deformation during the die passage leads to an oriented crystal structure formed with a grain size of 25–30 μm. Sample hardness measurement results are consistent with the results of structure analysis in the studied areas of the deformation zone. When the workpiece passes through the compression container abutment section, deformation heating occurs, which leads to a decrease in hardness from 93 to 67 HV. After the metal passes through the die, recrystallization processes continue in it leading to a slight increase in grain size and, accordingly, a decrease in hardness from 79 to 74 HV, which continues until the busbar contacts a cooling medium.

Made available in DSpace on 2021-06-25T10:24:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-06-01 The aim of the present study is evaluating the feasibility of Oxy Fuel Welding (OFW), using liquefied petroleum gas (LPG), for the joining of the glass fiber/polyetherimide composite and aluminum alloy 2024-T3, which combine the effectiveness of the joint and the low cost of operation. A statistical experimental design was performed to determine by OFW parameters, and the samples were welded and evaluated after Lap Shear Strength (LSS) loading as the planning response variable. For a better result of the joint strength, through the mechanical interlock between the laminate and the AA2024-T3, anodization process was performed. A maximum value of LSS with 6.20 MPa was obtained, with optimized values reaching 6.32 MPa. The results of mechanical resistance of the hybrid junction involving the anodized AA2024-T3 were doubled, being 13.80 MPa in relation to the maximum obtained from the joint without treatment, confirming the increase of the interaction between these two materials. This fact was confirmed by the roughness test and optical microscopy. After welding, the AA2024-T3 structure was converted into a new structure of equiaxed grains, from the recrystallization of the grains, the hardness value being reduced by approximately 24%. From the TGA and EDS analyses, there was no significant difference in the degradation temperature of the thermoplastic composite, confirming the efficacy of the process for hybrid joint AA2024-T3 and GF/PEI composite, and there is no indication of contaminant that could interfere with the quality of the weld. Materials and Technology Department School of Engineering São Paulo State University (UNESP) Technology School of Pindamonhangaba FATEC Materials and Technology Department School of Engineering São Paulo State University (UNESP)

The lightweight construction of steel structures is often limited by the mechanical properties of the weld metal. The strength values of modern base materials are not achieved in the weld metal. There is a considerable need to develop welding consumables that allow the processing of modern fine-grained structural steels without limiting their potential. The Physical Vapor Deposition (PVD) coating of welding wire electrodes can increase the strength of the weld metal of a Mn4Ni2CrMo welding wire electrode by up to 30%. By using different coating elements, the Hall–Petch relationship can be exploited and such an increase in strength can be achieved. Especially by applying titanium, vanadium, and yttrium coatings, the strength of the weld metal can be increased. Due to a multilayer structure of the coating, the weld metal and the process can be influenced independently of each other. The effects of mono-element coatings and multi-component coatings on the weld metal and the process are discussed. PVD coatings allow welding wire electrodes to be individually adapted to the requirements.

The effect of the austenitization route on the bainitic reaction kinetics of an alloyed (3.2C–2.8Si–1.8Ni–1.4Cu–0.4Mn–0.2Mo–0.1Cr) austempered ductile iron was studied. Two-step, conventional and rapid austenitization heat treatments were employed to produce different austenite grains sizes (94, 39, and 15 μm, respectively) and, in one case, secondary graphite precipitation. The overall bainitic transformation kinetic at 350 °C was described using the Johnson-Mehl-Avrami-Kolmogorov equation, and the values of the Avrami's adjustable parameters were discussed. The austempering reaction of the coarser austenite microstructure with secondary graphite precipitation featured the fastest kinetics, while the one derived from the medium austenite grain showed the slowest reaction rate. The increase in the graphite/austenite interfacial area reduced the half-transformation time (t50-value) by one magnitude compared to the austenite grain boundary area. The austempered samples from the rapid austenitization route comparatively featured the best tensile properties and the highest ISO and ASTM standards grades despite the considerable proportion of grain boundary allotriomorphic ferrite.

Available fatigue recommendations are typically developed for arc-welded joints. Some of them may need to be adjusted to fit fatigue life of joints manufactured with non-conventional welding techniques since they show different mechanical properties. Laser beam and friction stir welded butt and overlap joints made from aluminium are addressed in this paper focused on a comparison between different fatigue assessment methods. For an evaluation, S-N data from published papers was collected. Additionally, fatigue tests on laser beam and friction stir welded overlap joints were carried out. For a fatigue assessment, the nominal stress, notch stress and effective stress approach were applied. The comparison of the endurable nominal stresses showed a comparatively high fatigue strength of the tested friction stir welded overlap joints in comparison to literature data. The notches at the interface of the overlap joints were observed to have an asymmetric geometry compared to the common symmetric one, frequently found in literature, leading to a lower stress concentration. A comparison between endurable nominal stresses and the classes FAT 28 for butt welded and FAT 12 for overlap welded joints resulted in a conservative design for the majority of specimens. An evaluation based on notch stresses lead to partly non-conservative results that could be explained by the mild notches present at the laser-beam welded butt joints. For the effective stress approach, an evaluation of the micro-structural length was performed and a FAT-value is proposed.

A 50.8-mm-deep gas tungsten arc weld was made with matching filler metal in cast Haynes 282 alloy. The narrow-gap joint was filled with 104 weld beads. Visual and dye-penetrant inspection of cross-weld specimens indicated that the cast base metal contained numerous casting defects. No visible indications of physical defects were found in the weld deposit. The weld heat-affected zone was characterized by microcracking and localized recrystallization. The cause of the cracking could not be determined. Hardness testing showed that a softened region in the as-welded heat-affected zone was nearly eliminated by post-weld heat treatment. Tensile testing up to 816 °C showed that cross-weld specimen strengths ranged from 57 to 79% of the cast base metal tensile strength. The stress-rupture strengths of cross-weld specimens are within 20% of base metal reference data. Failures of both tensile and stress-rupture specimens occurred in the base metal.

The purpose of the paper is to determine the conditions for the maximum transition of fluorine from the technogenic raw materials of primary aluminum production (mature sludge) into solution under alkaline leaching. The object of research is the mature sludge, which is formed from technogenic finely dispersed materials of aluminum production in the baths with Soderberg anodes (tailings of coal foam flotation, gas cleaning sludge, electrostatic precipitator dust) and stored close to the enterprise. Analytical studies of the initial sample and leaching products have been carried out according to the certified methods using chemical, X-ray phase and titrimetric analysis methods. It is shown that, the main percentage of the three sludge components belongs to the dust of electrostatic precipitators (~ 79.7%) and coal foam flotation tailings (~ 15.8%). It has been determined that the gas cleaning sludge features the richest composition of useful components (in the sum of F, Na and Al ~ 63%). According to the data of X-ray phase analysis, the sludge sample from the sludge storage mainly contains cryolite (up to 78.7%), carbon (11.9%), calcium-magnesium carbonate from the dolomite series (4.44%), and trace amounts of corundum and fluorite. The results of the conducted experiments on fluorine leaching from the sludge sample by the caustic soda solution allow to estimate the main process parameters: temperature - 75–80°С, duration - 60 min, NaOH concentration - 3.0% (with the W:T ratio of 10:1 and a stirrer speed of ~ 1005– 1010 rpm). According to the analytical data on the chemical composition of leaching cake, the fluorine content in the solid phase reduces by 88.1%. The experiments carried out on alkaline leaching of fluorine from the sample of mature sludge formed under primary aluminum production by the electrolysis of cryolite-alumina melts in the baths with self-baking anodes allowed to find out that the maximum decrease of fluorine content in the sample is achieved under the conditions of maintaining the process parameters including temperature, duration, reagent concentration in optimal modes.

From the analysis of data on beneficial use of red mud and oily mill scale, a new direction of recycling has been formulated: the joint processing of these wastes to produce liquid products. Technological modeling of the stage of joint water treatment of a mixture of red mud and oily mill scale was performed at an enlarged laboratory unit. The yields and compositions of the products were determined. A batch of washed sludge was sent for research on obtaining ironcontaining raw materials for subsequent pyrometallurgical processing. With component ratio of 1:1, solid to liquid ratio of 4, temperature of 95 °C and duration of 2 hours, 6.3 kg of the mixture were processed, 6.58 kg of washed precipitate with a moisture content of 21.3 % and 12.6 dm3 of the final solution were obtained. The specific volume of water evaporation was determined to be 31.3 dm3/h per 1 m2 of pulp surface. Compositions of the precipitate iron (54.4 %) and the final solution (1.1 – 1.3 mg/dm3) were established, which indicates an almost complete accumulation of iron in the precipitate. Concentrations in the products of processing impurities were determined: silicon, aluminum, phosphorus, sulfur, sodium oxide and organics. According to the results, a technological scheme for the joint processing of red mud and oily mill scale was developed and ways of using the process products were outlined: sludge – for iron, filtrate – for industrial treatment, evaporated and wash water – for leaching. Using the example of cooperation between enterprises of the Kamensk-Uralsky Industrial Unit, the hardware process diagram is considered. It is advisable to use the data obtained to implement the technology, in particular, to develop technological regulations for the design of a pilot installation.

The article presents results of the research of high-temperature gas corrosion of sections of EcoSoderberg electrolyzers’ gas-collecting bells (GSB) made of high-strength VCh50 cast iron with spherical graphite. The gravimetric method was used to study the specific mass losses of the sections due to corrosion. The microstructure of cast iron, structure, chemical and phase composition of corrosion products were studied using optical, electron microscopy and electron microprobe analysis. It was established that the specific weight loss of the sections during operation reaches 0.36 – 0.46 g/(cm2·month). Corrosion of cast iron sections of EcoSoderberg electrolyzers’ GSB is characterized by high unevenness by area. There are cases of decommissioning sections due to local through “burnouts” with a weight loss of 19 – 24 kg. With relatively uniform corrosion, the maximum allowable weight loss of the sections is 25 – 30 kg. To make predictive estimates based on experimental data, dependence of the sections’ mass loss on the operating time was obtained. It was found that the corrosion products of the sections consist of iron oxides and alloying elements of cast iron. Most samples are characterized by increased content of C, S, F, K, Al, and Na. Corrosion products have a pronounced layered structure and contain a large number of defects in the form of pores and cracks. The layers differ in chemical, phase composition, and macrostructure. All the studied samples are characterized by cyclic alternation of relatively dense layers of iron oxides Fe2O3 and Fe3O4 and more porous layers between them. The layers are characterized by increased content of C and F. Sulfur is evenly distributed over the thickness of corrosion products. The studied samples of corrosion products have high defectiveness, friability, large number of pores, cracks, discontinuities, and low adhesion to the surface of cast iron. This is due to the presence of phases and compounds with different coefficients of thermal expansion. The mechanism of corrosion products layers formation was established and scientifically proved.

Sulfur is added to low-alloyed steel FAS3420H to improve the free-cutting property of the steel. Elongated MnS inclusions usually deteriorate the mechanical and process performance of steels, so the control of shape and size of MnS is essential. The statistical analysis of MnS inclusions in as-cast and rolled steels at different positions shows that the distribution and aspect ratio of MnS in rolled steel are closely related to the quantity and size of MnS in as-cast one. The in situ observation and experimental results reveal that homogenization treatment effectively reduced MnS inclusions size and transformed their shape to globule or ellipsoid. Significant change of quantity and size of MnS inclusions was identified only when the soaking time exceeds 5 h at 1,250℃. Additionally, a kinetic model is presented to quantitatively characterize the behavior of MnS inclusions during homogenization process.

The burden charging operation in blast furnace is one of the most important operations during iron-making process. In this paper, we focus on the study of precise burden charging operation, which involves two aspects: How to obtain and form the optimal burden surface shape. For the first problem, we construct a mapping model between the burden surface characteristic parameters and the comprehensive operational performance indicators of the blast furnace, and transform the search of optimal burden surface shape into the target optimization problem. The second problem refers to establishing a suitable burden charging strategy based on the basic burden surface and the optimal burden surface. In our work, by adaptively adjusting the opening degree of the throttle valve, it is possible to control accurate burden volume during the rotation of the charging chute, which can make sure to spill the appropriate burden volume on the suitable charging units. In the simulation of experiments, we collected the real industrial data during iron-making process and demonstrated the efficiency of the proposed model.

The article proposes a variant of the rheological model of hot deformation – the law of hyperbolic sine, which, in contrast to the standard one, takes into account not only the strain rate and process temperature, but also the strain ratio. Material constants included in the law of hyperbolic sine are replaced by polynomial functions of the strain ratio with coefficients calculated using the corresponding method developed. The paper describes applications of the rheological model proposed in low-density aluminum-lithium alloys 1424 of the Al–Mg–Li–Zn system and V-1461 of the Al–Cu–Li–Zn system, for which flow curves in the temperature range 400–480 °C and strain rate range 1–60 s–1 up to a strain ratio of 0.6 are defined by physical simulation at the Gleeble 3800 unit. The influence of the initial material state was also investigated – samples were taken from both the ingot and hot-rolled plates. Constants were determined for the rheological model of hot deformation including the Zener–Hollomon parameter and the law of hyperbolic sine for the entire range of stresses and strains. After approximating the dependences of the model parameters on true strains with a 4th degree polynomial law, a rheological model was created that describes the alloy behavior in the temperature-rate range under study. The features of changes in hyperbolic sine law parameters depending on the strain ratio were established. It was shown that, in general, parameters for the cast material are higher than for the rolled one. A comparison between the standard and proposed models showed that the use of the standard model over the entire strain interval leads to too high flow stress values (up to 12 %).

Hard alloys are popular materials widely used in the toolmaking industry. Refractory carbides included in their composition make carbide tools very hard (80 to 92 HRA) and heat-resistant (800 to 1000 °С) so as they can be used at cutting speeds several times higher than those used for high-speed steels. However, hard alloys differ from the latter by lower strength (1000 to 1500 MPa) and the absence of impact strength, and this constitutes an urgent problem. We studied the influence of thermal cycling modes on the mechanical and tribological properties of VK8 (WC–8Co) hard alloy used in the manufacture of cutters and cutting inserts for metal working on metal-cutting machines. As the object of study, we selected 5×5×35 mm billets made of VK8 (WC–8Co) alloy manufactured by powder metallurgy methods at Dimitrovgrad Tool Plant. The following criteria were selected for heat treatment mode evaluation: Vickers hardness, flexural strength, and mass wear resistance (as compared to the wear of asreceived samples that were not heat treated). Plates in the initial state and after heat treatment were subjected to abrasion tests. Wear results were evaluated by the change in the mass of plates. Regularities of the influence of various time and temperature conditions of heat treatment on the tribological properties of products made of VK group tungsten hard alloys were determined. An increase in the number of thermal cycling cycles improved such mechanical properties of the VK8 hard alloy as strength and hardness. When repeating the cycles five times, an increase in abrasive wear resistance was obtained compared to the initial nonheat-treated sample. The elemental composition of the VK8 hard alloy changed insignificantly after thermal cycling, only a slight increase in oxygen was observed on the surface of plates. The grain size after thermal cycling increased in comparison with the initial VK8 hard alloy. It was found that VK8 hard alloy thermocyclic treatment leads to a change in the phase composition. X-ray phase analysis showed the presence of a large amount of α-Co with an hcp-type lattice on the surface of a hard alloy and a solid solution of WC in α-Co. A change in the cobalt modification ratio causes a decrease in microstresses. An analysis of the carbide phase structure state showed that the size of crystallites and microstresses changed after thermal cycling. The lattice constant of the cobalt cubic solid solution decreased, which may indicate a decrease in the amount of tungsten carbide and carbon dissolved in it. Statistical processing of experimental results included the calculation of the average value of the mechanical property, its dispersion and standard deviation in the selected confidence interval.

This work presents the results of prior austenite state on the phase transformation behavior in a medium manganese steel alloyed with Al. The austenite was plastically deformed at two different temperatures. The first was at 1050 °C to ensure its recrystallization before cooling. The second treatment included deformation at 900 °C to keep high dislocation density in the austenite. The analysis of recrystallization process or its lack on the phase transformation behavior was analyzed. The study included thermodynamic calculations to analyze proper conditions of selected heat treatments. The dilatometric analysis of the phase transitions dependence on deformation temperatures was carried out. Deformation continuous cooling transformation diagrams were formed on this basis. The metallographic investigations were performed to determine microstructure constituents after cooling. The investigation proved the presence of ferrite untransformed during the austenitization step at 1100 °C. The dominant phase was bainite which was kept present up to 100 °C s−1 cooling rate. The amount of martensite increased with increasing the cooling rate. For the non-recrystallized austenite, more bainite was present in the microstructure for higher cooling rates compared to the recrystallized one. This was the result of higher density of preferable places for bainite nucleation in the non-recrystallized austenite. The Vickers hardness measurements were conducted after the applied heat treatments. The hardness of steel increased together with applying the higher cooling rates, which corresponded to the higher martensite amount. These values were higher for the non-recrystallized austenite because of higher dislocation density.

The article considers research on the history of nitrided ferroalloys appearance and development of technologies for nitrogen-containing steels and ligatures. The most important advantages of nitrogen as an alloying element are its availability and almost unlimited reserves in nature. The technology of nitrogen extraction does not cause any harm to the environment and is not accompanied by the formation of waste. New technologies of nitrided ferroalloys and new compositions of nitrogen-containing ligatures emerged as a response to the creation of new grades of nitrogen-alloyed steels. At the same time, researchers in Europe, the United States, and the Soviet Union made the greatest contribution to the development of nitrided steel and ferroalloys technology. Nitrided ferrochrome emerged from the need for alloying stainless steels of various classes. Nitrided ferrovanadium was created for microalloying high-strength low-alloy steels. For nitrogen alloying of transformer steel, an alloying material based on silicon nitride was developed. Nitrogen-containing compositions based on manganese are universal alloying materials for a wide range of applications. Technologies of nitrided ferroalloys developed in the direction of creating compositions with the maximum nitrogen content with minimal consumption of material resources. Currently, technologies for direct introduction of nitrogen gas into liquid metal during out-of-furnace processing are being successfully developed. Alloying with its solid carriers remains a universal method for smelting nitrogen-containing steels. Nitrogen in nature occurs exclusively in a gaseous form, so for introduction to steel, it is necessary to fix it in the composition of a solid substance. At the same time, such a nitrogen-containing material must be compatible with the steel melt and technological in use. This problem is completely solved by the technology of self-propagating high-temperature synthesis (SHS), which allows obtaining composite ferroalloys based on nitrides, with properties that are unattainable for the furnace process.

The regularities and formation mechanisms of structural-phase states and properties at different depths in the rail heads along the central axis and fillet after differential quenching of 100-meter rails and extremely long operation (with passed tonnage of 1411 million tons gross weight) have been revealed by the methods of the state-of-the-art physical materials science. As revealed, the differential quenching is accompanied by the formation of morphologically multi-aspect structure presented by grains of lamellar perlite, ferrite–carbide mixture, and structure-free ferrite. The steel structure is characterized by the α-Fe lattice parameter, the level of microstresses, the size of coherent-scattering region, the value of interlamellar distance, the scalar and excess dislocation densities. As shown, the extremely long operation of rails is accompanied by the numerous transformations of metal structure of rail head: firstly, a fracture of lamellar pearlite structure and a formation of subgrain structure of submicron (100–150 nm) sizes in the bulk of pearlite colonies; secondly, a precipitation of carbide phase particles of nanometer range along the boundaries and in the bulk of subgrains; thirdly, a microdistortion growth of steel crystal lattice; fourthly, a strain hardening of metal resulting in the increase (by 1.5-fold) in scalar and excess dislocation densities relative to the initial state. A long-term operation of rails is accompanied by the formation of structural constituent gradient consisting in a regular change in the relative content of lamellar pearlite, fractured pearlite, and structure of ferrite–carbide mixture along cross-section of railhead. As the distance to the rail fillet surface decreases, a relative content of metal volume with lamellar pearlite decreases, and that with the structure of fractured pearlite and ferrite–carbide mixture increases. As determined, the characteristic feature of ferrite–carbide mixture structure is a nanosize range of grains, subgrains and carbide-phase particles forming it. The size of grains and subgrains forming the type of structure varies in the limits of 40–70 nm; the size of carbide-phase particles located along the boundaries of grains and subgrains varies in the limits of 8–20 nm. A multiaspect character of steel strengthening is detected that is caused by several factors: firstly, the substructural strengthening due to the formation of fragment subboundaries, whose boundaries are stabilized by the carbide-phase particles; secondly, the strengthening by carbide-phase particles located in the bulk of fragments and on elements of dislocation substructure (dispersion hardening); thirdly, the strengthening caused by the precipitation of carbon atoms on dislocations (formation of Cottrell atmospheres); fourthly, the strengthening being introduced by internal stress fields due to incompatibility of crystal-lattices’ deformation of α-phase structural constituents and carbide-phase particles.

Weld defect recognition plays an important role in the manufacturing process of large-scale equipment. Traditional methods generally include several serial steps, such as image preprocessing, region segmentation, feature extraction, and type recognition. The results of each step have significant impact on the accuracy of the final defect identification. The convolutional neural network (CNN) has strong pattern recognition ability, which can overcome the above problem. However, there are two problems: one is that the pooling strategy has poor dynamic adaptability and the other is the insufficient feature selection ability. To overcome these problems, we propose a CNN-based weld defect recognition method, which includes an improved pooling strategy and an enhanced feature selection method. According to the characteristics of the weld defect image, an improved pooling strategy that considers the distribution of the pooling region and feature map is introduced. Additionally, in order to enhance the feature selection ability of the CNN, an enhanced feature selection method integrating the ReliefF algorithm with the CNN is proposed. A case study is presented for demonstrating the proposed techniques. The results show that the proposed method has higher accuracy than the traditional CNN method, and establish that the proposed CNN-based method is successfully applied for weld defect recognition.

It is found that when a tungsten anode is electrochemically dissolved in a acidic fluorides of alkali metals (K,Na)H2F3 and hydrogen fluoride at a temperature of t ~ 37°C, the resulting atomic fluorine reacts completely with tungsten to form WF6. The latter dissolves in the melt, forming complex compounds (K,Na)2WF8 and (K,Na)WF7, which is accompanied by an increase in the melting point of the electrolyte. The addition of up to 23 mol % LiF and saturation of the electrolyte by WF6 lowered its melting temperature below 18°C, which, in an electrochemical process at a temperature of 35–40°C and an anode current density of 0.3–0.5 A/cm2, made it possible to obtain simultaneously gaseous WF6 at the anode and H2 at the cathode. During the gas-phase deposition of tungsten, dense layers are formed from the resulting gaseous mixture with a stoichiometric ratio of components at a temperature of 550–600°C, and the resulting HF is captured by an electrolyte and used to produce a mixture of WF6 + H2, ensuring the circulation of reagents and the absence of stored waste. Based on the results, a short fluoride cycle in tungsten technology is presented. It uses two operations: the electrochemical synthesis of a gaseous mixture of WF6 + H2 in an electrolyzer with a filling anode made of fragments of metal tungsten and the reduction of WF6 by hydrogen with capture the resulting HF, allowing one to reduce the chain of technological devices in the cycle by almost 2 times with a significant reduction in production costs. The hardware and technological scheme of the production chain for the environmentally friendly production of tungsten products with a capacity of ~48.5 t/year, which can be replicated and modified to produce the necessary products, is presented.