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In developing materials for the nuclear industry, it is crucial to enhance both alloy composition and processing methods. This study focuses on investigations of applying radial-shear rolling (RSR) to a Zr-1%Nb alloy ingot, aiming to refine its microstructure and improve its properties for nuclear applications. This method, with complex vortex metal flow inside of a casted workpiece, has not been previously tested for processing zirconium ingots, so experimental verification of its applicability is of scientific interest. The 30 mm diameter ingot, produced by vacuum induction melting, was initially rolled to 20 mm at 800 °C to eliminate defects and refine the cast structure. A second rolling stage reduced the diameter to 13 mm at 530 °C, resulting in an ultrafine-grained structure. The RSR method effectively combines structural refinement and defect healing within fewer cycles, making it suitable for producing components for nuclear reactors. This approach demonstrates a potential reduction in traditional processing steps, providing a more efficient route for preparing high-quality materials for nuclear applications. [ABSTRACT FROM AUTHOR]

Cabeço Redondo is a fifth century BC archaeological site located on the left bank of the Guadiana river in the municipality of Moura (southern Portugal). The site was severely damaged by agricultural works in 1990, but among the preserved remains recorded by later archaeological surveys, a set of copper-based debris from a metallurgical workshop stands out. The set includes copper ingots, namely a large 6.4 kg fragment, a small plano-convex bronze ingot and numerous metal lumps and prills. Metal lumps and prills have a diverse elemental composition, characterised as pure copper, binary and ternary bronzes, very probably being intermediate or waste products from the manufacture of artefacts. In order to determine the provenance of the copper used by this workshop, nine samples including ingot fragments were selected for Pb isotope analysis by MC-ICP-MS, which results were complemented by minor and trace element contents determined by ICP-QMS. Crossing analytical data with archaeological evidence suggests that the majority of those metal items has an extra-peninsular provenance located on the Central Mediterranean. However, the small bronze ingot may have copper from the Iberian Peninsula, namely from the Torrubia mine (Los Pedroches Batholith complex, Central Iberian Zone). The combination of this evidence with other known imports from this period suggests an important trade originating in Central Mediterranean regions, whose products reach the inland regions of southwestern Iberian Peninsula via routes that are still uncertain. [ABSTRACT FROM AUTHOR]

Cyprus had an important place in the ancient Mediterranean trade thanks to its geostrategic location. The island, drew attention with its copper resources and ceramic products in the Bronze Age. Archaeological remains unearthed in Uluburun and Cape Gelidonya shipwrecks support this situation. The cargo of shipwrecks and the route they followed show both the extent of maritime trade during this period and Cyprus’ position in these commercial activities. The high ratio of Cypriot copper and ceramics to the total amount of goods in the shipwrecks is instructive in terms of understanding the role of Cyprus in the maritime activities. The hypothesis of their potential Cypriot origin is supported by the higher quantity of Cypriot-origin products found on these wrecks compared to others. The fact that Cyprus is an important port on the route followed by merchantships and even the view that it could be the initial departure point of them, makes it worth to consider. Accordingly, in this study, the Cape Gelidonya and Uluburun shipwrecks, and the Cypriot goods they contain are examined, and the active role of Cyprus in the maritime trade of the period is investigated. [ABSTRACT FROM AUTHOR]

In this work, a novel internal heat absorption technology using inorganic material rods is employed during the solidification process of steel ingots, aiming to control their solidification and improve the quality of the final product. The study investigates the effect of the insertion depth of inorganic materials on the solidification microstructure and macrosegregation of 2.5-ton 42CrMo ingots. The mechanical properties of samples from the product are also tested. A numerical simulation model for casting 2.5-ton ingots is established and implemented in Ansys Fluent fluid simulation software, with inorganic material rods set at different preset depths. The simulation explores the physical processes of the melting and floating of inorganic materials in molten steel, as well as their effects on the temperature and flow fields of the material. The results show that deeper insertion of inorganic materials (200 mm from the hot top) reduces the tendency for macrosegregation compared to that at the insertion depth of 100 mm. Specifically, the positive segregation area decreases by 10.35%, while the negative segregation area decreases by 15.32%. Moreover, deeper insertion results in a significant refinement of the solidification microstructure, ultimately enhancing the mechanical properties of the products machined from the ingots (i.e., the yield strength increased by 4.7%). The numerical simulation results indicate that as the placement depth of inorganic materials in the ingot mold increases, the cooling effect becomes more significant, the flow area of molten steel initiated by the inorganic materials expands, and the linear velocity of the double-circle flow increases. This further explains why the solidification quality of the ingots improves with the increasing placement depth of inorganic materials. [ABSTRACT FROM AUTHOR]

Previous research revealed that the quality of the ingots produced by different primary or secondary alloy suppliers can differ remarkably. In this way, the quality of the liquid metal and the castings produced from it can be affected by the impurity content of the ingots used as charge material. In this work, a modified reduced pressure test (RPT) technique, which is based on the remelting of samples extracted from ingots, was applied to investigate the quality of primary AlSi9Mn ingots made by horizontal direct-chill (HDC) casting and gravity casting techniques. For the evaluation of metal quality, image analysis of the cross sections was applied. Pore area fraction, number density, normalized bifilm index, and normalized total pore perimeter were determined, and the relationships between the different metrics were analyzed. The results were compared with the melt quality assessment of the as-melted batches made from the ingots. Solidification simulations, thermal analysis, and microstructural investigations were conducted to investigate the solidification conditions of traditional and remelted RPT samples. Based on the results, the HDC cast ingots possess lower oxide and gas concentrations, which can be traced back to the differences in the melt preparation and casting technologies of the ingots. The comparison of the parameters evaluated by image analysis revealed that there is a strong linear relationship between normalized bifilm index and normalized total pore perimeter. The possible sources of error in ingot quality evaluation are highlighted. [ABSTRACT FROM AUTHOR]

This study discusses the problem of continuous casting of high-alloy, martensitic steel into a (300–400) mm × (2000–2500) mm slabs for production of a 70–100 mm thick sheet. At the beginning of the technology development, the specialists encounter the formation of a considerable number of surface defects in the slabs, such as "scabs," "longitudinal cracks along the scabs," and "flash." The causes of the defects are determined during the course of this study. The shrinkage in the steel sample is measured, and that in the ingot crust in the casting mold is calculated. A new mold setting (tapering) is developed. The submerged nozzle design and slag-forming mixture composition for the mold are optimized. A new polynomial for calculating the liquidus temperature of high-carbon, high-chromium steels is developed and tested in practice. The use of the developed algorithm enabled to optimize the overheating of the steel. The application of the technology developed has considerably enhanced the quality of the slabs. [ABSTRACT FROM AUTHOR]

The results of experimental studies of the process of electroslag remelting of titanium in a chamber furnace at different values of pressure in the melting space, from vacuum to excess pressure, are given. Experiments were carried out during the melting of ingots with a diameter of 85 and 105 mm from titanium alloys VT1-0 and VT22 using fluoride-chloride flux AN-T4. The pressure of the inert gas in the furnace chamber was varied from 20 to 300 kPa. It is shown that in the entire studied range of pressures, the electroslag process proceeded stably with the formation of ingots with a high-quality side surface and a dense structure, without pores, slag inclusions and other internal defects. Experimental data on the effect of pressure in the melting space on the gas composition and structure of titanium ingots are given. the possibility of reducing the hydrogen content in titanium alloys by carrying out the electroslag process in vacuum conditions is shown. It was also established that the VT1-0 titanium ingot, melted under vacuum conditions, is characterized by a larger grain size compared to the ingot obtained under excess pressure. [ABSTRACT FROM AUTHOR]

Works have been performed on optimization of the technological scheme of producing ingots for consumable electrodes with a stable chemical composition and properties. The paper presents the results of studying an ingot of 195 mm diameter from a titanium aluminide-based alloy of Ti-28Al-7Nb-2Mo system, made by double electron beam remelting. Further ingot remelting in the arc furnace was performed, which allowed producing a homogeneous and defect-free ingot of an optimal composition of Ti-28Al-7Nb-2Mo-0.3 (Y, Re, B). The influence of modifying on the structure and properties was studied. It was determined that addition of surfactants promotes refining of the structural components and improvement of the alloy mechanical properties. [ABSTRACT FROM AUTHOR]

The rare earth metal ingots obtained by molten salt electrolysis method have oxide layers, salt layers, and other impurities on the surface, which require polishing processing. However, currently, manual polishing processing has problems such as low processing efficiency and resource waste. By designing a flexible end effector and adopting a parallel fuzzy Proportion Integration Differentiation (PID) control strategy for constant force control of the end effector, automation and high efficiency of rare earth metal ingot grinding are achieved.

In developing materials for the nuclear industry, it is crucial to enhance both alloy composition and processing methods. This study focuses on investigations of applying radial-shear rolling (RSR) to a Zr-1%Nb alloy ingot, aiming to refine its microstructure and improve its properties for nuclear applications. This method, with complex vortex metal flow inside of a casted workpiece, has not been previously tested for processing zirconium ingots, so experimental verification of its applicability is of scientific interest. The 30 mm diameter ingot, produced by vacuum induction melting, was initially rolled to 20 mm at 800 °C to eliminate defects and refine the cast structure. A second rolling stage reduced the diameter to 13 mm at 530 °C, resulting in an ultrafine-grained structure. The RSR method effectively combines structural refinement and defect healing within fewer cycles, making it suitable for producing components for nuclear reactors. This approach demonstrates a potential reduction in traditional processing steps, providing a more efficient route for preparing high-quality materials for nuclear applications.

Experimental-production melting of low-grade nickel scrap was conducted to obtain nickel ingots of not lower than NP2 grade, which are furtheron used to produce semi-finished products in the form of hot- and cold-formed seamless pipes, including capillary, thin-walled and particularly thick-walled pipes, rings, squares, hexagons, etc. It is shown that during electron beam melting a significant removal of impurity elements from the nickel scrap occurred, and metal quality began to correspond to nickel grade not lower than NP2. In order to further study the produced ingot quality, comprehensive research work was performed on manufacturing semi-finished products in the form of elongated soft rods of 40 mm diameter and wire of 3 mm diameter. It was determined that mechanical properties of semi-finished products from EBM nickel fully meet the standard requirements. It is shown that electron beam melting is an efficient method of producing nickel ingots from secondary raw materials, as it allows ensuring a high level of the produced material quality, and the semi-finished product quality fully meets the standard requirements by chemical composition, structure and mechanical properties. [ABSTRACT FROM AUTHOR]

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This paper investigates the behavior of transverse defects under significant total strain in conditions of complex vortex metal flow implemented through the radial shear rolling (RSR) method. The aim of this study is to assess the applicability of RSR processing for the in-depth transformation of small ingots of special steel into bars, particularly for the manufacturing of structural elements in specialized construction projects such as nuclear power plants. Although a substantial total strain is anticipated to enhance the steel structure and contribute to defect closure, the question of the development or closure of potential casting defects remains unclear. To address this issue, model tests were conducted to simulate the implementation of RSR processing. Defect behavior data under very complex vortex metal flow and high strain conditions were obtained for the first time and have scientific merit. A small steel ingot with a 32 mm diameter, containing a simulated artificial defect in the form of a transverse through-hole with a 5 mm diameter, was employed. During rolling, the workpiece diameter was progressively reduced by 2 mm with each subsequent pass, reaching a final diameter of 20 mm. Additionally, to provide a more detailed visualization of the defect evolution process, the same defect was modeled in an aluminum bar over six passes, and changes in defect volume and shape were analyzed after each pass. A highly detailed 3D visualization of the actual defect evolution was achieved based on cross-sections from experimental workpieces. These data corresponded to the total strain levels obtained by finite element method (FEM) simulation. Notably, a consistent similarity was observed between the test results for both metals, revealing a reduction in defect volume of up to 67.7%. The deformational welding of defects in the outer sections, encompassing one-third of the rod's radius, occurred in the initial passes. However, defects in the axial zone of the rods remained unclosed, lengthening and gradually decreasing proportionally to the elongation of the rod, akin to conventional rolling. Consequently, the radial shear rolling (RSR) method is unsuitable for ingots with substantial discontinuities in the axial zone post-casting. Nevertheless, the method ensures the total welding of defects located in the outer zones of the ingots, even with minor applied deformations and a slight decrease in the diameter of the deformed ingot. Such data were obtained for the first time and should contribute to future investigations in this field. [ABSTRACT FROM AUTHOR]

The paper presents the results of investigation of the influence of electroslag remelting on the properties of metal of ingots of high-manganese steel, alloyed by aluminium and chromium. Features of structure formation in high-alloy manganese steels are considered. These steels demonstrate ductility and lower density, alongside strength, and are difficult for pouring alloys, prone to hot cracking, formation of a coarse structure and development of macro- and microliquation. Studies have been performed, which confirm the conclusions that steels of this type require a thorough control of solidification conditions. Obtained results illustrate a significant influence of the cooling rate on cracking, manganese and aluminium segregation and parameters of the alloy dendritic structure. Electroslag remelting resulted in improvement of the structure and led to reduction of the size of nonmetallic inclusions in the studied metal without any significant changes in Mn, Al and Cr content, which is one of the conditions for producing large-sized homogeneous ingots. Metallographic examinations showed that the microstructure of all the studied steel specimens is characteristic for austenitic steel with dendritic crystal growth. Dendritic structure in the metal of ESR ingot is homogeneous, distances between the first and second order axes in the ingot middle and upper parts are equal to 136.6-146.5 and 60.54-8.92 μm, respectively. Completing formation of the required final microstructure of the studied steel takes place after further heat and thermodeformational treatment. ESR of cast billets allows reaching the required level of metal homogeneity and specified level of properties with a smaller number of stages and duration of thermomechanical treatment, and reducing resource consumption. [ABSTRACT FROM AUTHOR]

In this work, a novel internal heat absorption technology using inorganic material rods is employed during the solidification process of steel ingots, aiming to control their solidification and improve the quality of the final product. The study investigates the effect of the insertion depth of inorganic materials on the solidification microstructure and macrosegregation of 2.5-ton 42CrMo ingots. The mechanical properties of samples from the product are also tested. A numerical simulation model for casting 2.5-ton ingots is established and implemented in Ansys Fluent fluid simulation software, with inorganic material rods set at different preset depths. The simulation explores the physical processes of the melting and floating of inorganic materials in molten steel, as well as their effects on the temperature and flow fields of the material. The results show that deeper insertion of inorganic materials (200 mm from the hot top) reduces the tendency for macrosegregation compared to that at the insertion depth of 100 mm. Specifically, the positive segregation area decreases by 10.35%, while the negative segregation area decreases by 15.32%. Moreover, deeper insertion results in a significant refinement of the solidification microstructure, ultimately enhancing the mechanical properties of the products machined from the ingots (i.e., the yield strength increased by 4.7%). The numerical simulation results indicate that as the placement depth of inorganic materials in the ingot mold increases, the cooling effect becomes more significant, the flow area of molten steel initiated by the inorganic materials expands, and the linear velocity of the double-circle flow increases. This further explains why the solidification quality of the ingots improves with the increasing placement depth of inorganic materials.

In order to implement the electron beam melting technologies the E.O.Paton Electric Welding Institute of NASU developed a multifunctional electron beam unit UE-5810 of megawatt class, designed for producing ingots of titanium and its alloys of up to 20 tons weight. Description of a multipurpose universal electron beam unit UE-5810 and its specification are given. Functional features of the components of the unit, technological fixtures and electron guns are described. Electron beam unit UE-5810 is a reliable highly efficient installation of industrial type for melting highly reactive metals and alloys, as well as treatment of the produced ingots by glazing. [ABSTRACT FROM AUTHOR]

Hot compression tests are carried out at temperatures ranging from 900 °C to 1050 °C, strain rates ranging from 0.001s−1 to 1s−1 and deformation degree ranging from 60% to 70% on the Gleeble-3500 thermal simulator. Strain-compensated Arrhenius constitutive model, activation energy maps, hot processing maps and microstructure evolution are used to analyse the flow behavior of as-cast Ti-55511 alloy. At low temperature (≤950 °C), the flow softening behavior is mainly related to cracks, deformation bands (DBs) and DRV at high temperature (≥1000 °C) and high strain rate (≥0.1s−1), and DRV at high temperature (≥1000 °C) and low strain rate (≤0.01s−1). DBs and cracks are the main forms of hot deformation instability. There is a competitive relationship between DRV and DBs. Under high strain rate (≥0.1s−1), DBs are more likely to occur. Under low strain rate (

The research undertaken for this paper was inspired by the results of theoretical analyzes and strong experimental evidence confirming the possibility to induce the phenomenon of viscous flow (typical for liquids) in the process of low-temperature KOBO extrusion of metals. Thus, despite the constant solid state of the metal, the KOBO plastic deformation process requires much lower stress (low flow resistance) in comparison with conventional extrusion. On the other hand, the KOBO method is particularly attractive due to the generation of high strength properties in the product/extrudate favorable for low (room) temperature deformation as well as superplastic features at higher temperature ranges. This paper presents the results of the studies on the efficiency of low-temperature KOBO extrusion of hardly-deformable materials in massive form (Mg4Li, AK11, Cu6.5P) and fragmented fractions (2014, 7075, AZ91, titanium grade 2). Particular attention was paid to the structure and mechanical properties of the obtained extrudates, which were rated as exceedingly favorable. As such, the paper provides new technological arguments for the application of the KOBO method in plastic deformation of materials as it guarantees their functional properties. [ABSTRACT FROM AUTHOR]

The bulk Ti28Zr40Al20Nb12 refractory high entropy alloy (RHEA) ingot with total mass of 20 kg was produced by vacuum induction melting followed by mould casting. The bulk ingot shows dual-phase structure: the soft (Ti, Nb)-rich bcc matrix and the hard Al3Zr5-type hcp phase. The variation of cooling rate of the bulk ingot affects both microstructure and compression properties. Phase morphology changes from smaller grains at the edge to coarse grains at the center of the ingot. The total volume fraction of hcp phase at the edge is above 40%, which decreased to around 30% in the intermediate region and the center of the ingot. Whereas, the fraction of hcp phase inside the grains inversely increased to be larger than 10% at the center. Crushing destruction happened for all samples during compression. The compression strength for samples prepared from the edge of the ingot ranges from 640 to 944 MPa, which dramatically increases to over 1500 MPa for the intermediate regions. The highest strength of 1950 MPa was obtained in the specimen prepared from the center of the middle area of the ingot. When comparing the sample properties along the axial direction, it is found that the samples prepared from the bottom areas were of higher embrittlement than those from the top or middle areas due to larger cooling rate. The findings indicate that more efforts should be devoted to investigate the processing of bulk RHEAs ingot with respect to their potential application. [ABSTRACT FROM AUTHOR]

In this work, a study on large-diameter GaAs ingot growth is presented. Optimized temperature control technology is developed. Horizontal and vertical temperature application technologies with optimum conditions are investigated. The design result is verified through thermal analysis. In addition, polishing process technology for large-diameter GaAs substrates is developed. Simulation data were used to carry out experiments to determine the optimum temperature conditions. As a result of the defect analysis, the final manufacturing result is found to have excellent thickness variations. This presents the validity of the manufacturing process developed in this work. [ABSTRACT FROM AUTHOR]

Abstract Origins of medieval lead artefacts are hard to establish due to re-smelting and mixing. One can obtain conclusive evidence from ingots that served for bulk trade and originated directly from the mines. This paper aims to analyse the thirteenth century lead ingot from Wrocław (Poland). To establish its origins we analysed its structure and chemical composition. We used archaeometric methods: light and electron microscopic observations, X-ray fluorescence spectrometry, X-ray diffraction, infrared spectroscopy, inductively coupled plasma-optical emission spectrometry and Pb isotopic analysis. We compared our measurements with measurements of analogical ingot found on Kraków Market Square and a database of lead ores from Europe and the Middle East. The research indicated that both ingots originated from -Kraków and Silesia Upland Pb–Zn ore deposits (Poland), intensively mined from the twelfth century. The results complement the view of trade routes established based on written records and add valuable data for future comparative studies.

analysis of technologies, allowing titanium wastes to be used in the melting process in ingot production, was performed. It is shown that for this purpose, a promising and cost-effective schematic is the one which includes electroslag remelting with preliminary manufacture of a consumable electrode completely from standard wastes of sheet scraps of Vt1-0 titanium. the structure and properties of electroslag ingots of titanium of 90x90 mm cross-section and 85 mm diameter was studied. the ingots were produced with application of electroslag remelting in an open mould with sliding current conduit and the slag pool surface protection by argon. chemical composition of electroslag ingots of unalloyed titanium practically does not differ from that of titanium of Vt1-2, Vt1-l grades, and a whole range of grades of unalloyed titanium from foreign manufacturers, except for a somewhat higher content of oxygen and nitrogen. ultrasonic testing of the ingots did not reveal any internal defects. macrostructure, which was studied on longitudinal and transverse templates, is coarse-crystalline, dense and homogeneous without any defects of technological origin. The angle of inclination of the columnar crystallites to the ingot axis is 40x45°, grain size is 1.8-2.5 mm. The microstructure consists of transformed β-grains of 140175 μm size. After annealing (620 °), the mechanical properties of electroslag ingots were as follows: = 224; σt = 590 MPa; σ0.2 = 560 MPa; δ = 7.5 %; ψ = 13.5 %. Technical measures were determined to improve the ductility of electroslag titanium by reducing the content of oxygen and nitrogen in the ingots, and refining the cast grain size. Technological properties of electroslag titanium (cutting treatment and weldability) are on the level of VT1-L. The possibility of pressure treatment (hot forging) was established with deformation coefficients of 40 and 90 % of titanium from electroslag ingots. The manufactured semi-finished products did not have any internal or surface defects. [ABSTRACT FROM AUTHOR]

Proceeding from the results of the performed package of research work, it was established that the chemical composition of metal in the surface-melted layer of high-temperature titanium alloy VT9 corresponds to standard requirements; and a lowering of aluminium content, an alloying element with vapour pressure higher, and an increase in the content of molybdenum and zirconium, alloying elements with vapour pressure lower than that of titanium, is observed. Investigations of the surface-melted layer showed that the penetration depth of the surface layer in ingots of high-temperature titanium alloy VT9 of 600 mm diameter reaches 8 mm, the ingot surface is high-quality mirror-like with characteristic vacuum etching, even microrelief without cracks, tears or lacks-of-fusion, its roughness is within the range of 3-4 class at a waviness of 0.2-0.6 mm. The surface-melted layer of the ingot has a finer structure, compared to base metal, and it consists of areas with isolated a-plates of 1.0-2.5 µm thickness, where the a-plates are gathered into colonies of 10-50 µm width, and the gaps between them are taken up by dispersed particles of 1-2 μm size, which can be the products of metastable phase decomposition. [ABSTRACT FROM AUTHOR]

This paper investigates the behavior of transverse defects under significant total strain in conditions of complex vortex metal flow implemented through the radial shear rolling (RSR) method. The aim of this study is to assess the applicability of RSR processing for the in-depth transformation of small ingots of special steel into bars, particularly for the manufacturing of structural elements in specialized construction projects such as nuclear power plants. Although a substantial total strain is anticipated to enhance the steel structure and contribute to defect closure, the question of the development or closure of potential casting defects remains unclear. To address this issue, model tests were conducted to simulate the implementation of RSR processing. Defect behavior data under very complex vortex metal flow and high strain conditions were obtained for the first time and have scientific merit. A small steel ingot with a 32 mm diameter, containing a simulated artificial defect in the form of a transverse through-hole with a 5 mm diameter, was employed. During rolling, the workpiece diameter was progressively reduced by 2 mm with each subsequent pass, reaching a final diameter of 20 mm. Additionally, to provide a more detailed visualization of the defect evolution process, the same defect was modeled in an aluminum bar over six passes, and changes in defect volume and shape were analyzed after each pass. A highly detailed 3D visualization of the actual defect evolution was achieved based on cross-sections from experimental workpieces. These data corresponded to the total strain levels obtained by finite element method (FEM) simulation. Notably, a consistent similarity was observed between the test results for both metals, revealing a reduction in defect volume of up to 67.7%. The deformational welding of defects in the outer sections, encompassing one-third of the rod’s radius, occurred in the initial passes. However, defects in the axial zone of the rods remained unclosed, lengthening and gradually decreasing proportionally to the elongation of the rod, akin to conventional rolling. Consequently, the radial shear rolling (RSR) method is unsuitable for ingots with substantial discontinuities in the axial zone post-casting. Nevertheless, the method ensures the total welding of defects located in the outer zones of the ingots, even with minor applied deformations and a slight decrease in the diameter of the deformed ingot. Such data were obtained for the first time and should contribute to future investigations in this field.

The influence of permanent and pulsed longitudinal magnetic fields with the induction B = 0.16-0.30 T on the quality of outer surfaces of titanium ingots of 85 mm diameter, produced by esr process, was studied. It is shown that alongside the positive effects of magnetic field action, manifested in increase of ESR process efficiency, improvement of chemical homogeneity of the ingots, and refinement of their crystalline structure, application of magnetic fields leads to deterioration of the quality of formation of the ingot side surface. Here, the degree of surface deterioration depends on magnetic field induction and duration of its pulses. It is found that application of pulsed magnetic fields leads to deterioration of the ingot surfaces to a smaller extent than application of permanent magnetic fields. Described are the mechanisms which negatively affect the quality of ingot surface formation under the impact of the longitudinal magnetic field. They consist in removal and solidification of electrode drops near the mould walls and periodical change of the skull crust thickness as a result of the slag and metal pool melt vibration. [ABSTRACT FROM AUTHOR]

Laboratory experiments of steel ingots under three cooling modes and industrial trials of continuous casting (CC) blooms and billets were conducted, respectively. Corresponding results of the macrosegregation and the solidification structure were investigated. The mechanism of the positive segregation in the columnar-to-equiaxed transition (CET) zone was proposed. For laboratory experiments of ingots under three cooling modes, including water cooling, water cooling for 15 s followed by air cooling, and air cooling, obvious positive segregation was generated in the CET zone, and the degree of segregation was 1.024, 1.025, and 1.015, respectively. For industrial trials of three kinds of steel, CC bloom, round bloom, and billet, positive segregation was formed in the CET zone, and the degree of segregation was 1.06, 1.04, and 1.06, respectively. With the growth of columnar dendrites, solute elements were rejected on the liquid–solid interface. The downward flow near the columnar tip region and the upward flow in the center melt can carry the solute-rich melt to the molten pool. When the CET occurred, equiaxed grains accumulated around the columnar dendrite tips, and the solid network became less permeable. The liquid flow in the network was significantly suppressed, and thereby the solute-enriched liquid was 'arrested' locally. Solute-enrich liquid would be further sucked into the interdendritic region owing to the solidification shrinkage. As the sample was fully solidified, the obvious positive segregation was found at the CET zone. [ABSTRACT FROM AUTHOR]

Abstract—A technique is developed to calculate the head parameters for the production of nickel superalloy ingots by vacuum induction melting and subsequent casting of a melt into molds. It is based on methods of approximate calculations of heat conduction processes and the classical heat exchange theory. The application of this technique makes it possible to design the optimum head sizes in an automated mode with allowance for the type of head, the material of the insulation top insert, the mold wall thickness, the temperature and time parameters of casting, and other technological parameters and to ensure localization of shrinkage defects in the head part of the ingot and its dense macrostructure. The adequacy and reliability of the developed calculation technique has been experimentally confirmed on an ingot made of a granulated EP741NP nickel superalloy. The absence of shrinkage defects in the ingot volume makes it possible to use for the subsequent production of granules by centrifugal spraying without additional vacuum arc remelting, which significantly increases the profitability of production. [ABSTRACT FROM AUTHOR]

Origins of medieval lead artefacts are hard to establish due to re-smelting and mixing. One can obtain conclusive evidence from ingots that served for bulk trade and originated directly from the mines. This paper aims to analyse the thirteenth century lead ingot from Wrocław (Poland). To establish its origins we analysed its structure and chemical composition. We used archaeometric methods: light and electron microscopic observations, X-ray fluorescence spectrometry, X-ray diffraction, infrared spectroscopy, inductively coupled plasma-optical emission spectrometry and Pb isotopic analysis. We compared our measurements with measurements of analogical ingot found on Kraków Market Square and a database of lead ores from Europe and the Middle East. The research indicated that both ingots originated from -Kraków and Silesia Upland Pb–Zn ore deposits (Poland), intensively mined from the twelfth century. The results complement the view of trade routes established based on written records and add valuable data for future comparative studies. [ABSTRACT FROM AUTHOR]

The paper investigated the heat resistance of sheet materials based on the Cr-Fe-Co-Ni-Cu system, depending on copper content in the alloy. it is shown that the content of copper in the composition of high-entropy alloys significantly affects the heat resistance of the material: in the case of CrFeCoNiCu alloy foils, the increase in specific mass at a temperature of 900 °C occurs 8 times more intensively than in CrFeCoNi foils, due to activation of the diffusion of copper atoms, its coming to the surface of the foil and formation of scale based on CuO and NiO oxides with a significant number of defects in the structure. CrFeCoNi alloy foils are characterized by higher heat resistance due to formation of scale based on Cr2O3 oxide on the surface with fewer defects and greater continuity. the average mass growth rate of the CrFeCoNi alloy sample is about 0.041 mg/(cm²h). [ABSTRACT FROM AUTHOR]

A new method of upsetting the workpieces with conical ledges has been proposed and investigated in the paper. A workpiece's relative height before upsetting was H/D = 3.0. Stress–strain state (SSS) has been investigated to determine the level and sign of the compressive stresses in the workpiece. Moreover, the parameter of the stress state in the place location of the axial defects has been evaluated. The degree of axial defect closing and a convexity value has been determined. These parameters have been determined for different dimensions of diameters and heights. It has been established that an upsetting workpiece with conical ledges leads to a uniform strain distribution into the workpiece body. During upsetting on the lateral surface and in the axial zone, there are compressive stresses due to the appearance of a concave workpiece shape. Moreover, there is a decreasing dimension of the axial defects and convexity lateral surface. Effective workpiece geometrical parameters have been determined. Relative diameter (d/D) and height (h/D) of the ledges should be equal from 0.5 to 0.7 and from 0.4 to 0.6, respectively. Recommended degree of upsetting is 50%. Determined recommendations have been verified experimentally during forging ingot with 66,500 kg weight. Obtained experimental data confirmed the results of finite element method (FEM) modeling. The investigation results have been implemented in the industry. [ABSTRACT FROM AUTHOR]

The use of continuously cast round blooms as a substitute for cast ingots has attracted wide interest because it can improve yields and reduce operating costs through continuous operation. However, central voids and segregations, which are the most common internal defects in continuously cast round blooms, must be eliminated through the cogging process to ensure adequate mechanical properties. In general, because the diameter of a round bloom is not large owing to the limited facility capacity, the permissible amount of forging reduction may be insufficient to completely close the internal defects. Accordingly, it is necessary to apply a more efficient cogging method to eliminate internal defects, particularly central voids, in a round bloom. Therefore, an innovative square cogging process using a square-shaped billet was implemented in this study to concentrate deformations within the central region of a Ø 1000 mm round bloom. A comparison of shop-floor operations between round and square cogging processes for the manufacture of main shafts shows that the square cogging operation noticeably increases the void closure efficiency with a reduced number of forging blows. Furthermore, the square-cogged products show improved mechanical properties as a result of the enhanced forging effect. Finite element simulations of the square cogging process also confirm the experimental results and validate the feasibility of the square cogging process. [ABSTRACT FROM AUTHOR]

In this work, a study on large-diameter GaAs ingot growth is presented. Optimized temperature control technology is developed. Horizontal and vertical temperature application technologies with optimum conditions are investigated. The design result is verified through thermal analysis. In addition, polishing process technology for large-diameter GaAs substrates is developed. Simulation data were used to carry out experiments to determine the optimum temperature conditions. As a result of the defect analysis, the final manufacturing result is found to have excellent thickness variations. This presents the validity of the manufacturing process developed in this work.

A complex of research work was performed on the base of eBm technology to produce high-strength complex titanium alloys of Ti-Al-Zr-Si-Mo-Nb-Sn system with silicon content, higher than the thermodynamically stable value in the solid solution. alloys of this system are promising for creation of a new class of materials with a high level of heat-resistant characteristics. It is shown that EBM allows producing ingots of high-temperature titanium alloys of Ti-Al-Zr-Si-Mo-Nb-Sn system, which are characterized by sufficient chemical homogeneity and absence of casting defects. It is found that tin presence lowers silicon solubility in the test alloys and intensifies silicide release. Here the structure is also refined. It is found that additional alloying elements influence silicon solubility in titanium, forming complex silicides of (Zr, Ti)5si (ti, Zr)3si type in the test alloys. It is shown that the microstructure of the test cast alloys consists of platelike a-phase packets within primary ß-grains, having different crystallographic orientation. [ABSTRACT FROM AUTHOR]

To process ingots of FeGa alloy single crystals into wafers, Fe17% Ga alloy crystals were cut using multi-wire sawing or electric discharging and rolling. Further, their properties of magnetization and magnetostriction were analyzed using electron backscatter diffraction (EBSD) and X-ray diffraction (XRD). It was observed that the magnetization and magnetostriction curves changed with increasing rolling reduction. Although magnetization was negligibly affected by deformation, the shape of the magnetostriction curve of the as-grown crystal could be modified by a slight reduction in rolling or a slight plastic deformation. EBSD results show that rolling introduced dislocations to form heterogeneous dislocation cell walls and decreased the surface roughness of the wafers. The pole figures obtained by XRD indicate that the samples were single crystals; however, the crystal orientation was different from the ideal orientation after rolling. Residual stress measurements using the cos ¡ method revealed that compressive and tensile stresses remained in the polycrystalline surface layers of the samples cut by multiwire sawing and electric discharging, respectively. Moreover, the stresses were affected by the tensile strains or magnetic fields when the residual stresses were relatively small in the sample. Although the magnetization and magnetostriction of a single crystal are affected by rolling, they are not significantly reduced by small rolling reductions. [ABSTRACT FROM AUTHOR]

Complex works were performed to study the quality of wrought semi-finished products, manufactured from an ingot of VT9 titanium alloy. Electron beam remelting technology was used to produce ingots of 600 mm diameter and 1.5 m length, from which semi-finished products were manufactured in the form of hot-pressed rods of 315 mm diameter. Results of investigations of structural and mechanical properties of semi-finished products in the form of hot-pressed rods are given. It is shown that the metal of the produced ingots and wrought semi-finished products after the respective heat treatment meets the requirements of the standards. [ABSTRACT FROM AUTHOR]

For creation of the high-tech equipment that is used in energy, heavy engineering, chemistry and transport, the unique large-sized steel products are required. In the manufacture of such products, large forging ingots in the mass to 600 tons are used. However, an increase in the mass of the ingots leads to the formation of chemical and physical heterogeneity, enlargement and unfavorable distribution of non-metallic inclusions, of the development of segregation defects in them, which reduce the strength and exploitation characteristics of the metal. In this connection, the quality forgings and finished parts are not always meet the producing demands and the loss of metal, in the form of technological waste and rejects are reaching significant values. It is known that eccentric zonal segregation, especially it’s the most dangerous variety - cords, significantly reduce the quality and properties of products from large steel ingots. In connection with the continuous expansion of the production of large ingots, the problem of creating optimal technologies for their formation, which reduce or exclude the possibility of the formation of chemical heterogeneity and cords in steel during crystallization, it is currently important and relevant. In this paper it are presented the results of studies of the structure, gas distribution, physical and chemical heterogeneities in the cross section and height of an ingot in the mass of 140 tons, which was casted in vacuum from steel 25KHN3MFA. It is shown that depending on the temperature and time conditions of ingot hardening, among which the crystallization interval (due to the chemical composition of steels), cooling intensity in different volumes in height and cross section of ingot, temperature gradient before the crystallization front, solubility of alloying elements and gas content in the melt, etc. Based on this, when developing technology for large ingots to ensure their quality, optimal structure and properties should take into account not only their dimensions, but also the combination of these thermokinetic parameters on the crystallization process, dendritic structure formation, manifestations of liquation in different ingot volumes.

In connection with the need to reduce the negative impact of the main defects of the forging ingots, the changes in their thermal state due to endogenous vibrational processing of the melt during crystallization are studied. Vibration processing of an ingot of steel 40XH weighing 7.6 tons was carried out in the upper part for 13 min after the completion of casting of steel at a frequency of 50 Hz and an amplitude of 1.5 mm. Based on the results of temperature measurements of the side surfaces in the upper, middle and bottom parts of the vibrated and control ingots, the regression equations were obtained for the change in their thermal state during crystallization for 200 minutes. A regular increase in temperature was established under conditions of endogenous vibration processing up to 30 °С in the upper part of the ingot with its gradual decrease over 100 minutes, and in the middle part by 10-15 °С over 50 minutes. In the bottom part, no temperature differences were noted during the first 25 minutes. In the next time interval, the temperature of the research ingot steadily decreases by 35-50 °C compared with the control. The obtained results indicate an increase in temperature in the upper part of the experimental ingot due to endogenous vibration treatment of the solidifying melt and a regular redistribution of temperature fields along the height of the ingot. An increase in the temperature gradient in the indicated volumes of the ingot as a result of endogenous vibration processing leads to an increase in convection and mixing of the melt, advancement of the crystallization front mainly in the direction of the upper part, the formation of a fine-crystalline structure and a greater length of the bottom cone without contamination with non-metallic inclusions, a decrease in the manifestation of axial segregation and an increase in mechanical properties metal ingot. The use of endogenous vibration treatment of steel ingots during their crystallization is a promising technological solution that opens new opportunities for controlling the processes of crystallization and structure formation, improves the quality of metal properties of large forged ingots.

The method of upsetting of large ingots has been investigated in this work. The proposed method consists in upsetting of profiled workpieces with concave faces. An angle of the concave faces was 150°. A relative depth of the concave faces has been varied in range 15%…25% from workpiece's diameter. Strains effective and mean stresses in the longitudinal cross-section of the workpiece with concave faces after upsetting have been determined by FEM. A value of compressive stresses has been determined based on a parameter of the stress state. FEM allowed to find what a rational depth of the concave faces should be, which has to be 15 % from workpiece's diameter. Maximum closing of the internal defect take place for this depth of the concave faces. Results of the FEM have been tested by experimental investigations. It has been established that upsetting of the four-beam workpieces improved a quality of the massive parts.

It is shown that when specifying the efficiency of EBM process, the phenomenon of thermogravitational convection is a weighty factor, which determines the thermal state of the ingot. A mathematical model of interrelated hydrodynamic and thermal processes in the crystallizing metal, taking into account the phenomena of thermogravitational convection, was formulated for a steady-state mode of the process of electron beam melting of titanium into a straight-through cylindrical mould. The thermal state of the ingot as well as the position of the crystallization front at a continuous feeding of liquid titanium from the cold hearth into the mould depending on metal temperature at the inlet and speed of ingot drawing for a laminar mode of hydrodynamic flow in the liquid pool was determined. It is found that at increase of metal temperature at the inlet into the mould in the studied range (2040-2100 K) shifting of the point of maximum pool depth from the ingot axis becomes smaller. Calculations within the constructed mathematical model were used to study the impact of the rate of liquid metal feed from the cold hearth into the mould on the shape and depth of a liquid pool. It is found that at increase of ingot drawing rate by 30 % the liquid pool depth increases by 1.5 times, and the point of the maximum liquid pool depth becomes close to the ingot axis. 10 Ref., 1 Table, 9 Figures. [ABSTRACT FROM AUTHOR]

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The paper deals with the vibration effect on the porous structure of alloyed steel. It is shown that the use of vibration in this mode affects positively decreasing porosity and the nature of the pores in size distribution in the ingot. Mechanical properties of the ingot, such as tensile strength and toughness, after the vibration action are also improved.

Spent nickel‐metal hydride (NiMH) batteries contained some valuable metals which are worthy of recovery. This study focuses on the reclamation of spent NiMH batteries using an alternative approach, thermal separation process (TSP). Spent NiMH batteries were mixed with cullet, limestone, and dolomite. The mixture was heated to 1,450°C and cooled to room temperature without forced convection. During the TSP, the output‐materials were divided into slag, ingot, and flue gas according to the boiling points and densities of metals. Results show that metals having a relatively low boiling points, such as Cd, Hg, Pb, and Zn, were mostly vaporized into flue gas. Among the metals retained in molten materials, Co, Cu, Fe, and Ni predominately went into the bottom layer and formed the ingot; on the contrary, Al, Ca, Mg, and Si stayed in the upper layer and formed slag. Therefore, the main components of slag were Si (316,000 mg/kg), Ca (289,000 mg/kg), and Mg (32,400 mg/kg) and the major crystalline phases were CaSiO3, CaMgSi2O6, and Ca2MgSi2O7. The slag was pended as non‐hazardous materials and could be reused as road pavement or building materials. The ingot had high levels of Ni (408,000 mg/kg), Fe (349,000 mg/kg), and Co (55,400 mg/kg) and could act as an additive in stainless steel manufacturing process. [ABSTRACT FROM AUTHOR]

A stress-strain state and a resize of an axial defect during upsetting have been studied in the article. Theoretical research based on a FEM has been conducted. We upsetted cylindrical steel workpieces which had the axial defect equal to 10 % of the workpiece diameter. Upsetting has been carried out by flat, concave-conical and convex plates (solid or with hole). The results of the study show that a ratio of dimensions has the main influence on the workpiece shape. The maximal closure of the axial defect is provided with upsetting by concave-conical solid plates. Upsetting by flat plates does not provide the closure of axial defects. Convex plates provide the uniform stress-strain state along the workpiece cross section. The hole in the plates increases the non-uniformity of strain distribution and also does not provide the axial defects closure. [ABSTRACT FROM AUTHOR]

The aim of paper was determination of influence of the casting velocity in horizontal continuous casting process on solidification phenomenon and next primary structure of aluminum ingots. In the range of studies was conducted the experiment concerning continuous casting of Al ingots with diameter 30 mm at velocity from 30 to 80 mm/min. Moreover was developed adequate to the real the virtual model of cooled water continuous casting mould, which was used in simulation of solidification process of Al continuous ingot, made in ANSYS Fluent software. In result was determined the influence of casting velocity and temperature of cooling water on position of crystallization front inside the continuous casting mould. While the shape and size of grains in primary structure of Al continuous ingots were determined on the basis of metallographic macroscopic studies. On the basis of the results analysis was affirmed that increase of casting velocity strongly influences on position of crystallization front and causes increase of temperature of ingot leaving the continuous casting mould. In result the increase of casting velocity supposedly leads to decrease of temperature gradient on crystallization front what creates coarse grains in primary structure of aluminum continuous ingots and caused low usable properties i.e. suitability to plastic deformation.

The paper describes the process of ingot casting from a modelling material into a special ingot mould made for these tests. As a modelling material we chose stearin (tristearin, glycerol tristearate), which proved to be suitable for this kind of laboratory tests. Casting was done in two ways - using a vertical ingot mould and a horizontal one. Observation of the ingot after solidification confirmed the fact that the cavity filling took place in the laminar flow of the melt.

The microstructure and mechanical properties in submicrovolumes of lead brass of the LS59-1A brand are studied. Metallographic analysis of the structure of the samples under study is performed using scanning electron microscopy (EDS). It is revealed that globular inclusions of free lead (1–2 vol %), which are localized along grain boundaries in interdendritic regions, are also contained in the microstructure of LS59-1A brass along with main phases (the α solid solution of alloying elements in copper and β phase—a solid solution based on the CuZn electronic compound). In addition, exogenous CuO + ZnO nonmetallic inclusions and pores are revealed in the microstructure. Oxide inclusions and iron and manganese-containing compounds are localized along the interfaces of α and β phases. Hardness and Young modulus of α and β phases are measured by the nanoindentation method. An insignificant difference between the values of H for dendrites of the α phase and the interdendritic space of the β phase is found, which evidences a high degree of homogeneity of mechanical properties of the LS59-1A ingot. A calculation of the additional pressure appearing at the boundary of α and β phases when material is loaded by an external force due to the difference of Young moduli showed that it is 23-fold higher than the external force, which can be the cause of fracturing the LS59-1A ingots during mechanical treatment. These results are discussed from standpoints of modern notions on the metallographic quality-control method of brass ingots in manufacturing conditions. [ABSTRACT FROM AUTHOR]

Any metal must be processed from its ore before employing it in various industrial applications; this is the similar case with Silicon (Si) as well. Occurring in the form of silicates in the earth's crust, Si must be processed to achieve high purity for industrial applications. A major share of Si goes into the production of its wafers on which miniaturized circuits can be integrated and these wafers are also used in making solar cells. These wafers are produced by dividing Si chips into smaller parts, and the Si chips are produced by slicing Si ingots. Once the ingot is produced there is no scope to increase the purity of the Si, and the wafers will have purity less than or equal to the ingot purity and the solar cells produced will have equivalent conversion efficiency. Hence, the production of Si ingot plays a very crucial role at the back-end in determining the final purity of the wafer or efficiency of the solar cell. The pace at which the technology is developing today forecasts a huge demand of high purity Si wafers and alternate energy sources are also which in turn demands further increase in purity that makes the Si ingot production highly important. The present-day use of very large-scale integration techniques and the advancement towards the ultra-large-scale integration further makes Si chips foremost resourceful. The current review work aims to compile the capabilities of existing Si ingot production methods which are already employed in industries and production methods that are still being researched upon, and to present critical analysis which has been done to provide the method to be chosen to produce Si ingot based on application, production quality and quantity. [ABSTRACT FROM AUTHOR]

The regularities of the effect of the variation in the chemical composition of the new Russian β‑solidifying TiAl-alloy (Ti–44.5 Al–2 V–1 Nb–2 Cr/1 Zr–(0–0.1) Gd, at %) within the chromium content from 1.5 to 2.5 at % (2.0–3.5 wt %) and zirconium from 0.5 to 1.5 at % (1.2–3.5 wt %), as well as the effect of gadolinium microalloying on the phase composition and the structure of ingots, have been studied. The ingots were obtained using double vacuum-arc remelting with the subsequent vacuum-induction melting and pouring of the melt into the steel chill mold at the melting-casting unit with a cold crucible. It is shown that 0.1 at % gadolinium microaddition results in a decrease in the average size of the macro grains from 3000 ± 500 μm to 400 ± 80 μm in the peripheral part of the ingots after the first remelting. It was found that the phase composition of TiAl-alloy compositions with Cr and Zr is represented by three main phases: γ-TiAl, α2-Ti3Al, and β-phase. The volume fraction of β-phase does not exceed 2–3% in ingots containing Zr, while it reaches 5–6% in ingots containing Cr. It was revealed that the microstructure of the ingots of all studied chemical compositions has a lamellar morphology. Sprouting of lamellar colonies through the grain boundaries was noted for ingots containing Zr. [ABSTRACT FROM AUTHOR]