Artykuły (CN-jcme)

Permanent URI for this collectionhttps://repo.agh.edu.pl/handle/AGH/102800

Artykuły czasopisma Journal of Casting & Materials Engineering

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Access status: Open Access ,
3D Microstructure Reconstruction of Tetragonal Zirconia Polycrystalline
(AGH University Press, 2025) Grabowski, Grzegorz
The microstructure of a material is fundamental to its properties and behavior under mechanical and thermal loads. Understanding the internal structure of a material and controlling the microstructure at the stage of ceramic materials synthesis are essential for designing materials with desired properties. This study focuses on the three-dimensional reconstruction of the microstructure of yttria-stabilized tetragonal zirconia polycrystalline (TZP). The goal was to create accurate digital models of the microstructure which could be used for further material analysis. The study utilized images obtained through scanning electron microscopy (SEM), on the basis of which the fundamental stereological parameters were determined. The microstructure reconstruction was performed using the Laguerre tessellation method, allowing for the generation of three-dimensional digital models of the microstructure that represent the material’s internal structure. The results confirm that, based on the basic stereological parameters obtained from two-dimensional cross-sections, three-dimensional reconstruction of the microstructure of polycrystalline zirconia is possible. This work, therefore, represents a step towards the effective design of ceramic materials with high performance parameters, through the control and optimization of their microstructure.
Access status: Open Access ,
A casting mould for rapid tube hydroforming prototyping
(AGH University of Science and Technology Press, 2020) Kochański, Andrzej Witold; Sadłowska, Hanna
In recent years, hydroforming has clearly expanded its range of industrial applications due to the growing interest in products which combine high strength with low weight. A current limitation of this technology was its economically justified production volume since the costs of producing tools eliminates the possibility of using hydroforming technology in prototype and single part production. The paper presents a freshly patented solution that allows for single part hydroforming. The new technology combines traditional hydroforming machines with a new approach to tool production. The new rapid die is made quickly and cheaply. The use of materials known from the production of foundry moulds causes the die to deform during hydroforming, but it is a controlled deformation. Thanks to the use of numerical modelling, the deformation of the mould cavity is predicted and taken into account at the design stage. The article presents important issues that need to be considered in the design of this innovative process.
Access status: Open Access ,
A Characterization of the Impact Toughness of Hot-rolled HSLA Steel
(AGH University Press, 2024) Hamryszczak, Tomasz; Śleboda, Tomasz; Lypchanskyi, Oleksandr; Pańcikiewicz, Krzysztof
Due to the wide use of HSLA steels in difficult conditions, e.g. at low temperatures, it is extremely important to test the impact strength of these steels. This is equally important because most of those structures are made by welding these steels, and the welding process itself has a significant impact on the properties of joints and welding zones. In this work, the authors analyzed two selected representative HSLA steels rolled in the Krakow branch of ArcelorMittal Poland S.A. – the only place in Poland where HSLA steels in the form of hot-rolled strips can be produced on an industrial scale. Impact tests were performed in accordance with technical acceptance standards, and then the fracture surfaces after impact tests were characterized using light and scanning microscopy. In the next part of the work, a set of previously gathered data were analyzed to determine the influence of thermomechanical rolling process parameters on the level of impact strength and the influence of chemical composition on it.
Access status: Open Access ,
A diffusion model of binary systems controlled by chemical potential gradient
(AGH University Press, 2022) Wróbel, Marek; Burbelko, Andriy A.
The paper presents a model of diffusion in a single phase with chemical potential gradient as the driving force of the process. Fick's laws are strictly empirical and the assumption that the concentration gradients are the driving forces of diffusion is far from precise. Instead, the gradient of chemical potential $\mu_{i}$ of component i is the real driving force. The matter of governing equations of models that incorporate this approach will be raised and discussed in this article. One of more important features is the ability to acquire results where diffusion against the concentration gradient may occur. The presented model uses the Finite Difference Method (FDM) and employs the CALPHAD method to obtain chemical potentials. The calculations of chemical potential are carried out for instant conditions - temperature and composition - in the entire task domain by Thermo-Calc via a TQ-Interface. Then the heterogeneity of chemical potentials is translated into mass transfer for each individual element. Calculations of two modelling tasks for one-dimension diffusion field were carried out. First: isothermal conditions with linear initial composition distribution and second: constant temperature gradient with uniform chemical composition in the specimen. Results for two binary solid solutions: Fe-C and Fe-Si, in the FCC phase for the given tasks will be presented. Modelling allows us to estimate the time needed to reach a desired state in a particular equilibrium or quasi-equilibrium state. It also shows the path of the composition change during the process. This can be used to determine whether the system at some point is getting close to the formation of another phase due to significant deviation from its initial conditions.
Access status: Open Access ,
A morphological characterization of high yield chitin from periwinkle shells
(AGH University of Science and Technology Press, 2021) Chiosa Odili, Cletus; Gbenebor, Oluwashina Philips; Haffner, Henry Adekola; Adeosun, Samson Oluropo
Research on obtaining chitin from periwinkle shell is scarce due to the very low yield of chitin from this kind of shell. This study reports a method of processing periwinkle shells to obtain high yield, bio-medically suitable chitin. The experiment was designed using IM and 2M concentrations of HCl for demineralization and a 1M NaOH concentration for deproteinization. FTIR, SEM, XRD and DTA analytical tools were used to characterize the extracted chitin. The FTIR spectral, XRD patterns and SEM analysis, revealed the complete removal of calcium carbonate by the acid concentrations used. The particle-like form of periwinkle shell was transformed to sheet-like fiber and globular-like fiber of $\alpha$-chitin by increasing the concentration of HCl from1M to 2M respectively. The crystal size increased from 11.2Ǻ (1M HCl) to 13.4Ǻ (2M HCl). The yield of chitin from periwinkle shell also increased from 52% to 71% using 1M and 2M HCl respectively. Thus, acid concentrations can be used to alter the structure of chitin with different mechanical properties.
Access status: Open Access ,
A new flexible and economic technology for the low pressure sand casting of steel alloys
(AGH University of Science and Technology Press, 2021) Krumm, Steven; Scheidhauer, Nico; Wolf, Gotthard; Dommaschk, Claudia
Low pressure casting is a very well established process for the casting of aluminium alloys. In the field of ferrous materials, however, the process has so far only found a few applications. The crucial reasons for this are the low flexibility and poor economic efficiency of the existing technologies. Since 2016, a new technology has been developed at the Foundry Institute of the TU Bergakademie Freiberg, in which an induction crucible furnace can be used as a melting unit and, in combination with a cover including a casting pipe, as a casting unit. The new technology stands out from existing low-pressure casting technologies for ferrous materials, particularly in terms of its flexibility and cost-effectiveness. The main focus of the activities was the development of a casting pipe as well as the verification of its lifetime, the elaboration and verification of process parameters and sequences as well as the upscaling of the technology for an industrial application. In all considerations, the focus was on both the technical feasibility and the economic efficiency of the process. The result is extensive expertise that can be used in the future to offer a finished product for industrial applications as a plug-and-play solution together with an induction furnace construction company.
Access status: Open Access ,
A novel approach to quantifying the effect of the density of sand cores on their gas permeability
(AGH University Press, 2022) Sundaram, Dinesh; Svidró, József Tamás; Svidró, Judit; Diószegi, Attila
The density of moulding mixtures used in the foundry industry plays a significant role since it influences the strength, porosity, and permeability of moulds and cores. The latter is routinely tested in foundries using different solutions to control the properties of the moulding materials that are used to make moulds and cores. In this paper, the gas permeability of sand samples was measured using a custom-made setup to obtain the gas permeability in standard units instead of the usual permeability numbers (PN) with calibrated units. The aim of the work was to explore the effect of density variations in moulding materials on their gas permeabilities. Permeability in this work is quantified in SI units, square metres [m$^{2}$]. The setup works based on Darcy's law and the numbers obtained from the measurements can be used to deduce the gas permeability, $k$, of a sample. Two furan resin bonded mixtures with the same grain size distribution were hand-rammed with varying compaction forces to obtain a variation in density. Cylindrical samples (50 × 50 mm) were prepared using a silica sand aggregate sourced from a Swedish lake. The results of the measurement provided the difference in gas permeability between the samples that have varying densities. The results of permeability were then extrapolated by modifying the viscosity value of the air passed through the sample. In order to find the effect of apparent density variation on the pore characteristics of the samples, mercury intrusion porosimetry (MIP) was also performed. The results were in line with the gas permeability measurements.
Access status: Open Access ,
A simulation and experimental investigation of the thermal characteristics of refractory bricks produced using fireclay and agroforestry wastes
(AGH University Press, 2022) Obidiegwu, Eugenia Obiageli; Esezobor, David Ehigie; Mgbemere, Henry Ekene; Chiosa Odili, Cletus
Manufacturing and processing industries usually consume large quantities of materials and energy in the course of their operations. The energy supplied for high-temperature processes are used partially for the actual technical process and between 30 to 40% of the energy escapes through the walls of the reactor into the atmosphere, leading to a high degree of thermal inefficiency and fuel consumption. This paper studies the thermal behaviour of insulating refractory bricks produced from a blend of fireclay and agroforestry wastes. The fireclays used were obtained from Ukpor deposit in Anambra State (Latitude 5.95°N, Longitude 6.92°E), Osiele deposit in Abeokuta, Ogun State (Latitude 7.18°N, Longitude 3.45°E) and Kankara Katsina State (Latitude 11.93°N, Longitude 7.41°E), all of which are in Nigeria. Samples were prepared with various weight percentages (60-100 wt.%) clays and (0-40 wt.%) of agroforestry waste, with grain sizes between 212 and 600 µm. Raw materials and the developed refractory bricks were characterised using appropriate standard techniques. The chemical, mineralogical constituents and phases present in the microstructure were examined. Physical and thermo-mechanical properties were investigated. The insulating refractory bricks developed have porosity of 78.83% , cold crushing strength (CCS) 3.144 kN/m$^{2}$ and thermal conductivity 0.04-0.046 W/(m$\cdot$K) that compare favourably with imported bricks 75-85%, 2.756 kN/m$^{2}$ and 0.049 W/(m$\cdot$K) in both physical, mechanical and thermal properties respectively. The reason is that the agroforestry waste used (coconut shell), served to create the pores that improve insulation after burning. Also the ash that remains serves as reinforcement to improve the mechanical properties. The thermal behaviour of the bricks was studied using Finite Element Method and shows a strong correlation with the experimental findings. This indicates that the produced insulating bricks have the thermal properties required for insulation of furnaces.
Access status: Open Access ,
A statistical analysis of evaporative pattern casting process parameters for the production of aluminum alloy components
(AGH University of Science and Technology Press, 2020) Omidiji, Babatunde Victor
Four process parameters were investigated with the aim of determining their influence on the mechanical properties of some test castings, bars, cylinders and plates. The influence was quantified in terms of percentage contribution. Analysis of variance (ANOVA), regression, main effects and interaction effects plots were employed to carry out the statistical analysis. As regards the tensile strength of the test castings, the geometry of components (GOC) dominated, contributing 90.83% and the pouring temperature (PT) contributed 91.90% influence on the hardness property. These dominating potentials of these two parameters limited the interaction of the parameters studied in the research.
Access status: Open Access ,
A study of the properties of forming mixtures containing polystyrene wastes
(AGH University of Science and Technology Press, 2021) Dan, Olena; Trofimova, Larisa Alekseevna
Expanded polystyrene is widely used as a material for packaging, in modern construction as a heat and sound insulation layer, in thermal insulation systems for buildings, as well as tanks and pipelines. It is additionally used in foundry engineering for the production of models which are gasified during the production of castings from ferrous and non-ferrous alloys under the contact with liquid metal. The use of expanded polystyrene products is associated with waste generation, both in production and in consumption. About 40-50 kg/person of polystyrene waste is generated per year. The peculiarity of polymeric wastes is their resistance to aggressive environments. They do not rot and the destruction processes in natural conditions proceed rather slowly, with the formation of harmful substances that poison the environment. Therefore, the problem of the processing of waste from polymeric materials is of great importance, not only from the standpoint of environmental protection, but also due to the fact that in conditions of a shortage of polymer raw materials, this waste becomes a powerful raw material resource. This article describes the prospects for recycling expanded polystyrene wastes in foundry engineering. In this work, the properties of molding and core sands containing a combined binder, consisting of a solution of expanded polystyrene wastes in turpentine and clay were investigated, and their main characteristics (weight during stretching and crumbling) were determined. Molding and core mixtures, which contain only a binder in the form of a solution of expanded polystyrene in turpentine, have a crude strength of not more than 0.01 MPa. The introduction of a mixture of clay in the amount of 2-3% allows a crude strength of the mixture of up to 0.05 MPa to be obtained. After drying, the investigated mixtures containing a solution of expanded polystyrene wastes and clay have a tensile strength of up to 2.1 MPa. Mixtures into which a solution of polystyrene wastes and clay was introduced have an insignificant gas capacity and satisfactory gas permeability.
Access status: Open Access ,
Alloys for Hot Dip Galvanising on Thin-Walled Materials
(AGH University Press, 2024) Lewartowski, Piotr; Leszczyńska-Madej, Beata; Włoch, Grzegorz; Żabiński, Piotr
Wydział Metali Nieżelaznych
The article reviews alloy additives to zinc and their impact on the quality of coatings achieved on structural steel. It also analyses the impact of the concentration of acid used for the chemical stripping of raw material on the zinc coating thickness of the steel. The zinc layer thickness changed depending on the concentration of alloy elements in the bath. It was stated that aluminium and bismuth have a low impact on the decrease in zinc coating thickness, while in the case of tin, a small change to the content (from 0.6% to 0.8%) significantly decreased the zinc layer thickness. Furthermore, it was found that, during the hot dip galvanising of steel, particular alloy elements are extracted from the bath. This results in the need to supplement alloy elements through periodical melting in for the purpose of maintaining the assumed bath composition. It was observed that, together with the increase in alloy elements concentration, zinc uptake (galvanised component weight ratio to black component weight) decreases, improving the process economics.
Access status: Open Access ,
An analysis of the features of cast composite materials based on light alloys reinforced by particles
(AGH University of Science and Technology Press, 2022) Dan, Olena Leonìdìvna
Light alloys are widely used in industry and everyday life due to their high physical and mechanical properties, wear and corrosion resistance, as well as low cost. In this regard, the use of light alloys as a basis for composite materials is both justified and expedient. The potential of these materials has not been fully used to this day, despite the growing interest in metal matrix composites and extensive investigations aimed at the development of production technology and the introduction of advanced systems based on light matrices. The article presents a short review of the analysis of the main components of the technology of cast composite materials based on light alloys of aluminum and magnesium reinforced by particles. Particular attention is paid to the choice of the matrix alloy, the type, size and amount of reinforcing particles introduced into it, as well as the thermal-time and kinetic parameters of the process.
Access status: Open Access ,
An analysis of the prospects of the use of magnetic water treatment in foundry engineering
(AGH University Press, 2023) Dan, Leonid; Trofimova, Larisa Alekseevna
Scientists are currently focused on creating technologies that produce positive results without affecting the environment. One such technology is magnetic water treatment. In this paper, an analytical review of publications devoted to the application of magnetic treatment of water in various branches of engineering, agriculture, and medicine is carried out. Current views on the structure of water molecules, as well as the theories explaining the influence of the magnetic treatment of water on its properties, are reviewed. The results of studies of the influence of water treated by a magnetic field on the properties of molding sand are analyzed, including those in which the authors of the article took part. It is shown that the magnetic treatment of still water can increase the green strength of the molding sand containing this water from 0.035 to 0.052 MPa, and that of water in motion to 0.075 MPa. Thanks to this, the amount of binder in the molding sand can be reduced. It is concluded that the use of magnetically treated water in foundries is promising.
Access status: Open Access ,
An Analysis of Transient States in the Power Supply System of a Selected Industrial Robot
(AGH University Press, 2025) Nowocień, Sebastian; Ziółkowski, Eugeniusz
Industrial robots are controlled by dedicated controllers powered by a single-phase or three-phase power supply system. The main power parameters characterizing the power supply system of these robots are: nominal supply voltage (1-phase: 100–120 V, 200–240 V or 3-phase 200–575 V AC), frequency of the supply voltage (50 Hz or 60 Hz), the nominal power consumed by industrial robot. The dynamics of power consumption in the power supply system of the controlled robot can be studied by recording instan¬taneous values of voltages and currents in each phase of the power grid. In this article, results are presented for the measurements of mentioned instantaneous values for a chosen single-phase powered robot, taken by specialized recorder. The measurements obtained from the recorder allows the calculation of numerically various energetic values in the power supply system of the robot: peak-peak values, RMS values, coefficients of deformation and values of harmonic amplitudes (FFT), values of active, reactive and apparent power and the power coefficient (tg?). The analysis of the waveforms of the instantaneous values of voltage and current allows the determination of the occurrence of transient states during the work of robot axes and characterizing its duration and the range of value changes. The analyses conducted can be used to properly design the protection systems of the power supply system, the eventual selection of filters for higher harmonics, and to determine the effective power consumption of the studied robot. The analyses of the transient states which occurred during the work of the studied robot in this publication significantly expand the knowledge about the dynamics of power consumption and its possible impact on the quality of electricity in the power supply grid.
Access status: Open Access ,
An evaluation of combustion kinetics for the synthesis reaction of the reinforcing phase during casting
(AGH University of Science and Technology Press, 2020) Wiktor, Tomasz; Sobula, Sebastian; Burbelko, Andriy A.; Ptasznik, Michał
The computer modeling of the solidification process in castings with local composite reinforcement (LCR) obtained as a result of in situ reactions of self-propagating high temperature synthesis (SHS) is difficult due to limited data on the thermo-physical parameters of exothermic effects and the kinetics of the synthesis reaction. In the present study, Hadfield cast steel casting was manufactured with LCR containing titanium carbide particles obtained in situ by the SHS method. Reaction kinetics of titanium carbide synthesis in the composite casting were determined on the basis of temperature measurements in the area of LCR during the process. For the estimation of the reaction, the Fourier Thermal Analysis method was used. The paper presents the results of temperature measurement and the results of the calculation of SHS reaction kinetics. It was found that the reaction time under the conditions of the analyzed casting is below 3 s.
Access status: Open Access ,
An evaluation of the effect of ultrasonic degassing on components produced by high pressure die casting
(AGH University of Science and Technology Press, 2020) Silva López, Manel da; Bajusz, Attila; Pabel, Thomas; Petkov, Tose; Plantà, Xavier
Ultrasonic treatment is known to be efficient for aluminium melt degassing with the additional benefits of being both economical and environment friendly. This paper describes the effect of ultrasonic degassing on the preparation of an AlSi9Cu3(Fe) alloy for High Pressure Die Casting (HPDC). The degassing efficiency was assessed in terms of the indirect evaluation of the melt, by means of the reduced pressure test and the porosity evaluation of the cast parts. Additionally, the corresponding hydrogen content was estimated with an experimental equation reported in the literature. Ultrasonic degassing shows greater efficiency in terms of hydrogen removal from the melt than conventional N$_{2}$ + Ar lance bubbling. Components produced by HPDC without degassing, with ultrasonic degassing and with lance degassing, were analysed by computed tomography and by metallography. The results show that the components produced by HPDC after ultrasonic degassing have a similar porosity level to components degassed with conventional lance bubbling, both showing an important improvement over components produced without degassing treatment. Hardness values were similar for all different treatment conditions and well over the minimum value established for the alloy by the corresponding standard.
Access status: Open Access ,
An Experimental Derivation of Transient Nonuniform External Boundary Conditions for the Solidification Process Modeling of Equiaxed Investment Castings
(AGH University Press, 2024) Olson, Weston; Stemmler, Michael; Fernandez, Erik; Kapat, Jayanta
The external heat transfer mechanisms acting on the external mold surfaces for equiaxed casting processes are very complex. The mechanisms are multi-mode, transient, and nonuniform, consisting of very complex radiative and convective definitions. In this work, a real-life mold, SGT6-5000 FD 3/4 Blade 4 cast in Alloy-247, was instrumented with thermocouples and temperature readings were recorded throughout the entire casting sequence of events. Analytical models based on the first law of thermodynamics, Fourier’s law, Newton’s Law of Cooling, and diffuse gray radiation for an N-sided enclosure were developed to use the thermocouple data as input to back calculate the emissivity of the mold, as well as the spatially varying heat transfer coefficients for a number of local regions. The derived external heat transfer mechanisms are presented as transient Biot numbers. The derived emissivity and nonuniform heat transfer coefficients for these surfaces were then validated in ProCAST numerical simulation by comparing the external mold temperature profiles. An extensive iterative, curve fitting, extrapolating, and averaging procedure was exercised to derive an expression for emissivity across the entire temperature range associated with the casting process. The predicted temperatures on the nodes corresponding to the thermocouple locations agree within reasonable error with the experimental data. The model also qualitatively predicted the shrinkage porosity detected via x-ray imaging for this casting. The current study confirms the hypothesis of previous work by the current authors with respect to the transient nonuniform boundary condition concept. Unique values of heat transfer coefficients were observed at different vertical positions along the airfoil. The analytical models were also able to capture phenomena associated with specific sequences of the casting process. This work provides the analytical models, and procedure, needed to derive these spatially varying conditions. The current authors contribute to the intellectual know-how of the large gas turbine casting industry which by other foundries is considered highly proprietary and strictly confidential. This paper should be used to set the precedence for how foundries derive and validate the external boundary conditions used in solidification process modeling.
Access status: Open Access ,
An IT system for the remote burden optimization of foundry furnaces
(AGH University of Science and Technology Press, 2021) Ziółkowski, Eugeniusz
The burden calculations for foundry furnaces are one of the most important steps in preparing the production of liquid casting alloys. These calculations, due to the usually large number of input materials and chemical elements, are realized by numerical methods. These methods are implemented in some spreadsheets, universal mathematical programs or in specialized programs for foundry engineering. The paper describes a computerized system for remote calculations of optimal burden. The technological, economic, and organizational features of implementing IT system have been presented, also taking into account its safety of use.
Access status: Open Access ,
Analysis and evaluation of effect of manganese content on properties of EN AC 46000 aluminum alloy
(AGH University of Science and Technology Press, 2019) Pasternak, Martyna; Brzeziński, Marcin; Piwowarczyk, Gabriela
This article is the effect of industrial work and many surveys in the one of the Polish foundries that specialize in aluminum alloys. The main goal of our explorations is to evaluate the influence of manganese on Al-Si alloy properties. In die-cast alloys, it is recommended to use larger amounts of iron to reduce the impact on the pressure chamber and mold. Manganese neutralizes the harmful effect of iron by changing the morphology of the separated brittle ferrous phases. The unfavorable form of the iron-containing phases in the form of long needles changes into the forms of fine compact crystals, which are less harmful to the mechanical properties. Nowadays, the main client requirement is to obtain the right parameters at the best price. Specifically, the customer is in the automotive industry, where new technologies provide a connection between the high quality and low weight of car parts [1-3].
Access status: Open Access ,
Analysis of cooling curves of nodular cast iron
(AGH University of Science and Technology Press, 2018) Bartošová, Marianna; Pribulová, Alena; Futáš, Peter; Eperješi, Štefan
The solidification of cast iron is a complex process with characterized entrance and marginal conditions. Thermal analysis is one of the processes that allows us to observe the solidification of alloys. There is a possibility of gaining information about the melted cast iron quality and predicting the final properties of the cast by evaluating the scanned cooling curves by solidification (stable and metastable system). This article deals with the study and analysis of cooling curves taken from production conditions of a foundry during ductile cast iron production. The aim is to discover the reproduction and reliability of the thermal analysis results of cast iron. The study of the progress of the cooling curves and their first derivation to follow the reactions of the curves to changing factors in the production process.