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Tematyka referatów prezentowanych w trakcie Międzynarodowej Konferencji Naukowej „KLASTER-ODLEWNICTWO-PRZYSZŁOŚĆ”

12.09.2014

Szanowni Państwo poniżej przedstawiamy streszczenia referatów zaprezentowanych w trakcie Międzynarodowej Konferencji Naukowej „KLASTER-ODLEWNICTWO-PRZYSZŁOŚĆ”.

Pełna treść artykułów dostępna jest dla Członków Klastra po zalogowaniu w zakładce Download/Artykuły branżowe.

 

Possibilities of Spent Foundry Sand Treatment

Greta MARUSKINOVA, Andrea MISKUFOVA, Tomas HAVLIK, Ivana KOBIALKOVA, Iveta VASKOVA

Abstract: Used foundry sand is one of the wastes generated in the foundry industry. Since it presents the bulk of the foundry waste, this work deals with precisely this kind of waste. In the paper, the possibility to spend foundry sand processing by mechanical, pneumatic, thermal and wet regeneration is presented and discussed. The characteristics and classification of foundry sand and the existence of possible pollutants in different types of moulds is also mentioned.

Keywords: Spent foundry sand, Green sand, Chemically bonded sand, Mechanical regeneration, Thermal regeneration, Pneumatic regeneration, Wet regeneration.

 

Treatment of Spent Foundry Sand Generated in the Casting of Aluminium Alloys

Ivana KOBIALKOVA, Andrea MISKUFOVA, Tomas HAVLIK, Greta MARUSKINOVA, Iveta VASKOVA

Abstract: This work is focused on study of the effect of thermal regeneration of spent foundry sand generated in the casting of aluminium alloys. The experiments of thermal regeneration were carried out in a temperature range 300–600°C and air flow range 0–3000 ml.min–1. The result of thermal regeneration is removal of carbon which covers surface of spent foundry sand. By thermal regeneration, significant reduction of carbon content (about 30 times less carbon) was achieved. The most effective combination of heating temperature and air flow can be considered 500–600°C with the air flow from 1500 to 3000 ml.min-1and time of thermal regeneration 15 minutes. In comparison with already published works it has been found that regeneration of spent foundry sand does not require higher temperatures, for example in the range of 800–1200°C. Airflow has a positive effect on the thermal regeneration in the treatment of spent foundry sand.

Keywords: Spent foundry sand, Aluminium, Waste, Thermal regeneration.

 

Polysaccharides for the Use in Foundry Industry

Karolina KACZMARSKA, Beata GRABOWSKA

Abstract: The article is a review of practical issues connected with an application of polysaccharides in the foundry industry, with particular emphasis on their use as an innovative green binding material for the moulds and cores production. The work includes technologies based primarily on the starch polysaccharide. It discusses a method of dispensing material as a main component of the binder, but also as an additive to improve the properties of the moulding sand with bentonite. The authors are focused on appropriateness of implementing technology on an industrial scale to moulding and core-bound starch-based binders and modified starch. The paper presents also the advantages and limitations resulting from the physicochemical properties of the polymer and discusses technological parameters of moulding with the addition of starch binders.

Keywords: Innovative green binders, Moulding sands, Organic additives, Polysaccharides, Starch.

 

Modification of Organic Foundry Binders with ZnO Nanoparticles

Emilia WILDHIRT, Angelika KMITA, Jarosław JAKUBSKI, Barbara HUTERA

Abstract: Nanotechnology is a broad interdisciplinary branch of science, enabling unlimited possibilities, covering issues from fields such as mechanics, chemistry, physics, materials engineering, bioengineering, or biomedical engineering. Nanotechnology covers issues related to the design, creation, and use of materials with at least one dimension whose natural unit is a calibrator [1–2]. This article discusses issues related to the way of producing nanoparticles. It shows a wide range of applications of nanomaterials in the various areas of human life. It also presents the initial results of tests carried out on friable self-curing masses of synthetic resins, with the addition of the modifier. For the test, the thermal method of producing metal oxide nanoparticles was adopted. ZnO nanoparticles originated in the thermal decomposition process were used for this purpose. Developed was the way of introduction and the influence of modifier quantity on mechanical properties and the service life of the masses. Modification of binder was conducted using urea resin furfuryl. Modifier was used in the form of suspension of ZnO nanoparticles in ethanol.

Keywords: Nanomaterials, Moulding sands, Modification, Organic binder, Nanoparticles.

 

Produce of Cores by Cold Box Technology

Iveta VASKOVÁ, Peter ŠEBEK

Abstract: The Cold Box technology was evolved in the late 1960s in the USA and this is up to this day the most frequently used core making technology by shoot for series production. Modern binders have supra specific strengths, better storage life of the mixture, and better core resistance towards humidity. The veining characteristics of all binder systems are related to the type of the aggregate used. Silica sands undergo a distinct expansion. This expansion often results in formation of a crack into which molten metal can penetrate. The end result is a vein. This paper describes reasons of the veining creation and possibilities of their elimination.

Keywords: Veining, Cold box process, Silica sand, Molten metal.

 

The Management of the Dust from the Mechanical Reclamation of the Spent Moulding Sand

Jadwida KAMIŃSKA, Angelika KMITA Ewa PAMUŁA

Abstract: Selfsetting sands with furan resins are still the largest use of SMS with synthetic resins. They can be used to prepare forms and cores of different sizes and shapes, for casting all types of alloys [1–3]. This work presents the results of reclamation of furan resin sand. Reclamation of the spent moulding sand was performed in the test apparatus AT-2. Granulation tests of the dust from the dedusting of the mechanical reclamation process were also carried out for the moulding sand with furan resin.

Keywords: Moulding sands, Furan resin, Reclaimed, After reclamation dust, Granulation.

 

Abrasion Resistance of the Wood for Foundry Tooling Used in Microwave Field

Beata OPYD, Mateusz STACHOWICZ, Kazimierz GRANAT

Abstract: The paper presents the results of research on abrasion resistance of three wood species (pine, beech, and pear) widely used for foundry tooling. Durability of foundry tooling depends on working conditions and abrasive properties of moulding materials, of which the main component are different sandmix bases. Abrasive tests with abrasive material (medium-size high-silica sand) were carried out by means of apparatus T-07 for the samples of the wood, prepared in three different directions (longitudinal, transverse, and axial). It was found that the average abrasion index of pine wood is similar to the average abrasion index of plastics PTFE. It was noticed that, for all wood species, the abrasion resistance caused by loose abrasive material was the highest in the direction perpendicular to the rings.

Keywords: Abrasive wear resistance, Foundry tooling, Wood, Silica sand, Microwaves.

 

Evaluation of Microwave Heating Process of Foundry Materials

Mateusz STACHOWICZ, Beata OPYD, Kazimierz GRANAT

Abstract: This work presents results of research on the influence of water glass kind and amount of binding agent on the basic parameter which is the tensile strength of moulding sands hardened with innovative microwave heating. It has been found that on hardening process has a beneficial influence on the power of microwaves. The influence of microwave hardening process has been observed in case of three kinds of binding agents available on the market (137,140, and 145). Microwave hardening of water glass mouldings sands guarantees, apart from a significant process time reduction, a full stabilisation of their properties and allows for reduction of amount of the used binding agent. Microwave heating of water glass moulding sands, through suitable process parameter selection, results in the possibility to forecast and control their properties.

Keywords: Foundry, Moulding sands, Microwave heating, Water glass, Tensile strength.

 

Using Rapid Prototyping (FFF) to Execute Casting Patterns

Konrad KOWALSKI, Dariusz PAJĄK

Abstract: The subject of the article is the use of the Rapid Prototyping (FFF) method to execute the casting model of the rotor. The method involves depositing of the melted material layer by layer until the final object is created. With this method it is possible to make the casting patterns faster. This work presents the characteristics of the FFF method, the process of performing the foundry model, and the practical use of the model.

Keywords: Rapid prototyping, FFF, FDM, Molten material depositing method, Casting patterns

 

Mechanical Properties of AlSi10MgMn Alloy with Elevated Iron Level

Mária ŽIHALOVÁ, Dana BOLIBRUCHOVÁ

Abstract: Application of the secondary aluminium alloys is strongly influenced by iron level of the selected alloy. Knowledge of iron impact on mechanical properties of alloy can lead to optimisation of castings production together with reduction of castings cost. Aluminium alloy AlSi10MgMn was used to evaluate iron influence at elevated iron level. Tensile strength, elongation, and Brinell hardness were chosen as the analysed mechanical properties.

Keywords: AlSi10MgMn alloy, Iron effect, Tensile strength, Elongation, Brinell hardness

 

Thermal Deformation of Moulding Sands with Hydrated Sodium Silicate Modified with Al2O3

Natalia KAŹNICA, Aleksandra GRABARCZYK, Katarzyna MAJOR-GABRYŚ Jarosław JAKUBSKI

Abstract: In the context of this article, authors attempted to assess the influence of α-Al2O3 and γ-Al2O3 nanoparticles on thermal deformation of self-hardened moulding sands with hydrated sodium silicate as a binder. In the research, different amounts of hydrated sodium silicate and different amounts of nanoparticles were used to determine their influence on the parameter of hot distortion. The range of researched concentrations varied from 0% to 5% for both α- and γ-Al2O3 nanoparticles. The research shows that in the examined concentration range of α- and γ-Al2O3, additives in the range of temperatures from 0°C to 250°C do not show a significant impact on hot distortion parameter of moulding sands with hydrated sodium silicate. However, their influence on thermal deformation of moulding sands in higher temperatures is still not certain and requires further research.

Keywords: Moulding sands, Hydrated sodium silicate, Thermal deformation, α-Al2O3, γ-Al2O3.

 

Diagnostics of Pressure Die Casting Machines Control Systems

Łukasz PAŁYGA, Mateusz STACHOWICZ, Kazimierz GRANAT

Abstract: The article presents the results of the diagnostics of the pressure die casting machine BÜHLER, Type H630-B, after its modernisation with a PLC controller in which the control system was completely changed to more efficient and suitable for data acquisition. For the evaluation of the control system modernisation benefits, a dedicated measuring device was used which, due to its specific structure, allows to determine the impact of the technical state of die casting machine on the quality of produced castings during the process of casting machine diagnostic. Pressure die castings were made with an alloy EN AB-46000 (AlSi9Cu3). Based on the analysis of destructive and non-destructive research results of the castings made this way, it was possible to determine a relationship between the parameters of their production and the current technical condition of the pressure die casting machine.

Keywords: Pressure die casting, Control system, Pouring parameters, Modernisation, PLC controller.

 

Effect of Heat Treatment on Intermetallic Phases in Al-Si Alloys

Lukáš RICHTÁRECH, Eva KUCHARČÍKOVÁ, Dana BOLIBRUCHOVÁ

Abstract: This article deals with influence of iron based phases by heat treatment. Iron is one of the most common impurities that can be found Al-Si alloys type. It is impossible to remove iron from melt by standard operations but it is possible to eliminate its negative influence by heat treatment that affects segregation of intermetallics in less harmful type.

Keywords: Iron based phases, Heat treatment, Secondary Al-Si alloy.

 

Mechanical Properties of Pattern Wax Used in the Precision Casting Process

Alicja Bałkowiec, Hubert Matysiak, Robert Biernacki, Roman Haratym, Krzysztof Kurzydłowski

Abstract: The aim of the presented research was to compare the mechanical properties of sprue wax and pattern wax for the manufacture of aircraft engine turbine components. The tests were applied to two commercial mass models, produced by the leading manufacturers of wax masses for precision casting. Tests were performed on samples which were injected into a steel mould, in conditions corresponding to those used of the industrial process. Measurements of hardness, creep resistance, and bending strength test were taken. Measurements of hardness and creep resistance were conducted for different temperature ranges, allowing to determine changes in mechanical properties of the wax, depending on the temperature. A comparison of the wax mass properties was performed.

Keywords: Pattern wax, Creep resistance, Mechanical properties, Hardness, Precision casting.

 

Influence of Modification and Heat Treatment on Mechanical Properties of the AlSi7Mg0.3 Alloy

Jaromir CAIS, Jaroslava SVOBODOVA, Viktoria WEISS

Abstract: The process of modification and heat treatment are ways to improve mechanical properties of aluminium alloys. The article examines the influence of collective modifications with strontium and antimony on mechanical properties of heat-treated samples of AlSi7Mg0.3 (A356) alloy. During the experiment, three sets of castings (of 4 pieces each) of alloy AlSi7Mg0.3 were made with content 0.04 wt.% Sr and with content 0.005, 0.007, and 0.01 wt.% Sb. All of the cast samples were then heat treated and subjected to static tension test. The present experiment and subsequent analysis are parts of a larger research project that is carried out at the Faculty of Production Technology and Management, University of Jan Evangelista in Ústí nad Labem.

Keywords: Heat treatment, Mechanical properties, Modification, Aluminium alloys, AlSi7Mg0.3 alloy.

 

Influence of the Mould Cooling Process on the Structure and Selected Mechanical Properties AlZn5.5MgCu Alloy Before and After Homogenisation

Viktoria WEISS, Jaroslava SVOBODA, Jaromir CAIS

Abstract: This article deals with the influence of casting moulds (metal, bentonite sand) on the AlZn5.5MgCu alloy structure and selected mechanical properties of this alloy. The type of casting mould can significantly influence the origin and scope of crystalline segregation and its further homogenising temperature process. The research is focused on the origin and scope of crystalline segregation and its removal with homogenising annealing at which we observe the influence of individual factors affecting the diffusion process. These factors include the temperature of homogenising annealing, length of keeping at the soak temperature, and size of the diffusion paths. The length of diffusion paths directly relates to the size of dendritic cells which are dependent on the chosen casting mould for casting (metal mould or bentonite mould). For the measurement of heat transfer from the mould by means of thermocouples, a plaster mould was also used in the experiment.

Keywords: Theory of crystallisation, Heat treatment, Homogenisation annealing, AlZn5.5MgCu alloy, Crystal segregation.

 

Rating Homogenising Annealing of the Alloy AlCu4MgMn Image Analysis and EDX Analysis

Viktoria WEISS, Jaroslava SVOBODOVA

Abstract: Homogenisation is defined as a method of heat treatment which consists in holding a casting for some time at a high temperature near the liquidus (approx. 0.7 to 0.8 the melting temperature) to eliminate chemical inhomogeneity diffusion processes. The cause of segregation is selective crystal solidification in the gradual change in composition of the solid phase. Melting starts to appear after certain of the hypothermia during cooling, and the growth of nuclei in accordance with the general laws of crystallisation. Each rigid layer has a different chemical composition. The first part of the solid phase shows low concentration of the element, and the last one, on the contrary, very high. Susceptibility to crystal alloy segregation is the greater, the larger is the temperature interval between solidification of alloys and the horizontal distance between the liquidus and solidus lines. Crystal segregation will also increase with increasing content of alloying elements which in these experimental alloys constituted 6–9% by weight. Crystal segregation can be reduced by diffusion, for which it is necessary to create conditions by homogenisation annealing.

Keywords: Theory of crystallisation, Heat treatment, Homogenisation annealing, AlCu4MgMn alloy, Crystal segregation.

 

Practical Application of Pb-Sn Alloys in Artistic Casting

Emilia WILDHIRT, Gabriela SIKORA, Angelika KMITA

Abstract: This work is related to the practical application of the alloys of Pb-Sn phase diagram. Currently, due to the hazardous properties of lead, there is a common trend to replace it and reduce the use of this element in everyday articles. This is difficult to accept in practice because even the smallest addition of lead improves fluidity and surface quality of the casting. Alloys of the Pb-Sn phase diagram are characterised by a very low melting point and a very good fluidity. These qualities are the reason for which these alloys are also used in artistic and precision foundry. The study reports an attempt to obtain an artistic casting with the use of metal mould. Problems that occur during casting an alloy with low melting point alloy in a chill mould are presented. Further, the degree of filling the mould was determined depending on the mould preheating temperature before pouring. Moreover, an estimate for thickness of the thinnest wall of the artistic casting was determined depending on the mould preheating temperature.

Keywords: Art casting, Pb-Sn alloys, Chill mould, Low-melting alloy, Pb-Sn alloy applications.

 

Cu Based Composite Materials Reinforced with Al2O3 Fibres

Krzysztof NAPLOCHA, Jacek W. KACZMAR

Abstract: Manufacturing method and strengthening effect in composite materials based on pure Cu strengthened with alumina fibres was discussed. Comprehensive technology including preparing of preforms and direct squeeze casting infiltration was presented. For infiltration Cu characterised by melting point of 1083°C, special processing parameters and construction of the mould was applied. Cu based composites were reinforced with 10 and 20 vol.% of Saffil alumina fibres. Using silica binder in wet forming process and next firing at high temperature, strong and suitable for the pressure infiltration preforms were produced characterised by the open porosity. Fibres uniformly distributed in the matrix were wetted by the matrix, without significant porosity at the matrix-strengthening fibres interface. Their appropriate content can effectively improve hardness, mechanical strength, and wear properties of composite materials. Though the composite Cu-based materials showed slightly reduced thermal conductivity comparing to non-reinforced Cu, they can be recommend for possible automotive applications.

Keywords: Composite materials, Ceramic preforms, Infiltration, Cu.

 

The Assessment of Graphite Precipitates in Spheroidised Low-Aluminium Cast Iron

Marek SOIŃSKI, Aneta JAKUBUS, Paulina KORDAS, Katarzyna SKURKA

Abstract: The work compares graphite precipitates occurring in cast iron containing either about 4% or about 8% of aluminium, spheroidised with cerium mixture and graphitised with ferrosilicon. Computer image analysis was used to determine the area of microsection occupied by graphite precipitates, as well as their perimeters and their number, the results being grouped according to the three ranges of graphite shape factor. It has been found that the area occupied by graphite precipitates in the examined cast iron with higher aluminium content was reduced nearly by half with respect to the cast iron with 4% aluminium, and their number was simultaneously lessened by almost 40%. It is connected both with the fact that Al addition in cast iron reduces carbon solubility in the alloy, and with the presence of Fe3AlCx carbide in the microstructure of cast iron containing 8% of aluminium. It should be noticed that the average size of graphite precipitates was equal to about 7 μm for both alloys; the percentage distribution of graphite area, perimeter, and number of precipitates between the assumed ranges of shape factor were also of similar character.

Keywords: Metallography, Cast iron, Aluminium, Spheroidisation, Graphite precipitates.

 

Wear Resistance of Grey Cast Iron Pair after Friction Hardening

Ihor HUREY, Volodymyr GUREY, Tetyana HUREY, Petro DMYTERKO

Abstract: It is shown that the friction hardening of grey cast iron SCh 20 essentially increases the wear resistance under the friction without lubrication. Thus, under the friction a grey cast iron-grey cast iron couple, the wear resistance of plates after friction hardening increases 2.6–2.8 times, and in fixed plates working with them in a couple — 1.8–1.9 times in comparison with nonhardening pair. Nonhardening couple is not serviceable by unit pressure more than 0.4 MPa, and hardening works normally.

Keywords: Wear resistance, Friction hardening, Dry friction, Friction coefficient, Temperature.

 

Resistance to Wear of Austempered Ductile Iron with 3.6–3.8% of Silicon

Andrzej KOCHAŃSKI, Anna KRZYŃSKA Józef PIOTROWSKI

Abstract: The results of studies of wear resistance of ADI are presented. For evaluation of wear resistance, six types of ADI were chosen with two different chemical compositions and three heat treatments. The specimens were cut from ADI test YII type casting heat treated in the Institute of Manufacturing Technologies in Warsaw. The three-cylinder-cone wear method was used for the wear resistance experiment. The specimens had the shape of a 21 mm long cylinder with diameter of 8 mm. The load was up to over 10 N. It was concluded that the wear resistance of ADI with higher amount of Si is slightly better.

Keywords: Austempered Ductile Iron, Wear resistance, Mechanical properties.

 

Evaluation of IN713C Microstructure by Advanced Research Techniques

Hubert MATYSIAK, Alicja BAŁKOWIEC, Krzysztof KURZYDŁOWSKI

Abstract: The paper presents a wide range of test method from the field of materials engineering on the example of IN713C alloy microstructure investigation. The observed samples were in the as-cast state or after the creep test. Differential thermal analysis (DTA), optical microscopy (LM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterise the sample microstructure. Measurements of chemical composition in microareas were performed with the use of energy dispersive spectrometry (EDS), while the phase identification was conducted with the use of X-ray diffraction (XRD) and electron diffraction. Obtained results enabled identification of elements of the microstructure. The sequence of separation during solidification and cooling of the alloy was described. The comparison of microhardness, chemical composition, and particle size of γ′ phase in the areas of dendrites and interdendritic areas was provided. On the basis of observations the description of the changes in the IN713C microstructure under simulation exploitation conditions were provided.

Keywords: IN713C, Microstructure, Material engineering, Degradation

 

Quality Assessment of the Zinc Coating on the Products Produced from Steel, Cast Steel, and Cast Iron

Dorota SIEKANIEC, Andrzej SZCZĘSNY

Abstract: The article contains the results of the protective coating formed during hot dip galvanising treatment on the surface of steel, cast steel, and cast iron. Zinc coatings are among the best methods of protection against corrosion of alloys of iron with coal in terms of both economic and ecological aspects. Castings from steel and cast steel were galvanised in industrial conditions, while iron castings in the Laboratory of Casting Surface Engineering, Department of Cast Alloys and Composites. The following study evaluated the quality and morphology of the protective coating on different products obtained from Fe-C alloys and corrosion resistance in salt spray chamber on samples of cast iron. Based on the studies it has been found that the thinnest and most regular zinc coating had been formed on the steel surface. On the surface of cast steel and cast iron, coating was irregular with clearly increased participation phase. In all cases, compact and continuous zinc coating was obtained.

Keywords: Hot dip galvanising, Coating, Steel, Cast steel, Cast iron.

 

Application of a Voronoi Polyhedron in the Modelling of Equiaxed Grain Growth

Jacek POCZĄTEK, Andriy BURBELKO

Abstract: The aim of the paper is to presents a mathematical model of the equiaxial grains solidification. For this purpose, a mathematical model describing the field of element concentration in an non-spherical Elementary Diffusion Micro-Field (EMDF) during the solidification of an eutectic nodular graphite iron and after its solidification as well as Pb-Bi alloy during peritectic solidification is created. A characteristic feature of the model is an inclusion of random contacts between adjacent grains thus generating nonspherical shape of the growing grain. For a description of polycrystalline structures in computational tasks, Voronoi polyhedrons are used. In this case, the walls of this polyhedron are fragments of planes perpendicular to the segments joining the "nuclei" and dividing these segments into two equal parts. The specific shape and volume of this polyhedron, as well as the number of faces and edges, depend on the distribution of the nearest neighbouring "nuclei". Structure of this type is formed in the case of an immediate nucleation of the grains and their spherical growth at an equal rate. The shape of such a grain is called Averaged Voronoi Polyhedron (AVP). The results obtained from the solidification simulation of binary peritectic Pb-Bi system were compared with results of an experiment.

Keywords: Voronoi polyhedron, Equiaxed solidification, Modelling, Diffusion

 

The Thermal Efficiency of Welding Process Thin Sheet of Inconel 718 Alloy

Agnieszka JĘDRUSIK, Bogdan KUPIEC, Mykola KORENIVSKYI

Abstract: The article examines the coefficients of thermal efficiency as a function of laser power when using a laser TruLaser Robot 5020 for welding thin sheet metal of nickel matrix alloy Inconel 718. In welding two sheets with thicknesses of 0.7 mm and 0.9 mm, the welding speed Vs = 25 mm/s and laser power of 400–700 W was used. The focal length of the laser was 200 mm. A water-cooled flow calorimeter with output of 6 l/min was used for the performance tests. The results show that with the increase of the laser power, coefficients of thermal efficiency ηc and the linear energy values E change.

Keywords: Laser welding, Thermal efficiency of a process, Inconel 718 nickel alloy, TruLaser Robot 5020

 

Influence of Linear Arc Energy in Welding Inconel 625 on Structure and Properties

Robert KOCUREK

Abstract: The use of welding technology for joining responsible elements made of creep-resisting nickel alloys may pose some problems. An important factor in the welding process, which affects the quality of the welded joints, can be the amount of energy supplied to the weld area. Linear arc energy is an important technological parameter because it affects the cooling rate, and this in turn may affect the structure and mechanical properties of the fusion weld. This study investigated the relationship between the linear arc energy of welding and the structure and properties. For this purpose, technological welding test have been performed with Inconel 625 alloy joined by gas tungsten arc welding (TIG). The research methodology included metallographic macro- and microstructure, as well as hardness measurements. The results can be a useful tool for comparison of welding procedures carried out with the same method.

Keywords: Power energy, Gas tungsten arc welding, Creep nickel alloys, Linear arc energy, Microstructure, Mechanical properties.

 

Application of Computer Support for Porosity Prediction

Marek Brůna, Richard Pastirčák

Abstract: The final integrity of a casting is greatly influenced by the presence of porosity. An innovative way to predict presence of porosity is the use of modern computer simulation programs. The main aim of the executed experiments is to verify possibilities of this promising method of porosity prediction. A calculation of advanced porosity prediction was performed for aluminium alloys by advanced porosity module included in ProCAST software. This calculation takes into account all basic phenomena, which are at the origin of micro- and macro-porosity. For the purpose of the experiment, a mould with specific shape, known as the Sanduhrprobe, was used. Materials used in experiments were not loaded from software database, because results could be distorted by deviations from particular material we used. To achieve precise results, we used thermal analysis to get accurate data about used alloys. Important solidification events, which affect porosity formation, such as recalescence and nucleation undercooling temperature, coherence point, and rigidity point have been determined from cooling curves and their first derivatives. These data were then included in the database of simulation software and used in the simulation process.

Keywords: Simulation, Thermal analysis, Porosity, Aluminium alloys.

 

Analysis of the Applicability of Percolation Theory in Studies of Polycrystalline Materials

Wojciech Trzaskowski, Dawid Myszka, Michał Jesiotr

Abstract: The article presents an analysis of the possibilities of using percolation theory in studies of polycrystalline materials. So far, the issue was little used for such materials. Initially, the term "percolation effect” described, above all, the permeation (seepage) of a liquid through porous structures and has been widely used in the study of filters for such media as water. Besides, this method was also applied in the field of polymer cross-linking studies, formation of composites with particular emphasis on the conductive composites, and many other applications where stochastic systems have been described [1, 3]. Observation of polycrystalline materials and explanation of a number of conditions occurring in it with the help of that theory is an unprecedented practice which deviates far from the current use of the phenomenon. Polycrystalline materials are characterised by a high complexity which results in difficulty in applying this theory in practice. To take up the topic, one must connect the basic techniques related to microstructure image capturing with appropriate software to facilitate the analysis of the obtained data. Currently on the market there is no software available to enable automated image analysis for the purpose of percolation theory. In order to have a better understanding of the relationship linking the phenomenon of percolation in polycrystalline materials in addition to the typical image analysis, it will be necessary to acquire accurate data regarding the basic material properties. The result of the work will be the necessary information regarding the applicability of percolation theory in the field of materials research. The article brings a new look at  the metallographic observation of polycrystalline materials and uses the idea of the theory unpopular in metallography.

Keywords: Percolation theory, Metallography, Image analysis, Computer analysis, Polycrystalline materials.

 

CALPHAD Method — a Modern Technique of Thermodynamic Data Acquisition

Marek WRÓBEL

Abstract: As, most of the times, the very first question about CALPHAD computations is: What can I actually calculate using such software?, this paper gives few examples of obtaining results and interpreting them as well as defines the extent of usefulness for such approach. Examples of calculations helping with determination of casting or heat treatment temperature have been shown. A way of resolving the issue of influence of specific elements on the binary Fe-C was given. The idea of equilibrium and nonequilibrium calculations has been given to help realise that computation results are just a part of understanding the system of consideration and that the need for proper knowledge about the material is required to get to reliable conclusions. It has been demonstrated that CALPHAD method, thanks to ability to make computations in systems of high order and considering many phases, is extremely helpful tool in the field of modelling of phase transformations.

Keywords: CALPHAD, Phase diagrams, Material properties.

 

Management of Tool Economy in Machining Line of Bodies

Jan Jaworski, Rafał Kluz

Abstract: Organisation of tool economy largely depends on the profile of the production plant. In large industrial enterprises, the economy of both tools and tool flow should be considered. Furthermore, the process of tool flow is also important for the selection of cutting parameters for implemented production process. In machining operations, an important issue is to identify tools that will limit the size of a production cycle and provide the required tool life. The article presents an analysis of tool wear on the brackets machining line and shows that the cost of the tool wear is about 4.2% of parts costs. This corresponds to the costs reported in the literature and proves that the line possibilities can reduce these costs by proper selection of the cutting parameters.

Keywords: Production cycle, Blade durability, Tool economy.

 

Dynamical Mechanisms of Increasing of the Steel Local Strength

Valeriy V. Shevelya, Andrzej Trytek, Julia S. Sokolan, Galyna S. Kalda

Abstract: Effect of loading-speeding parameters of sliding friction of carbon steel in connection with its rheological properties acquired in the result of thermal treatment was researched. Effective mechanisms of decreasing of the dynamical tensity and increasing of the wear resistance of the frictional contact were examined. Role of structural and tribological factors optimisation of which promotes realisation of reinforcing mechanisms was studied.

Keywords: Wear resistance, Thermal treatment, Internal friction, Rheology, Relaxation, Dislocations, Tempering, Ageing; Acoustic emission; Sliding velocity.

 

Effect of Load on the Wear Mechanism in Steel

Nykolay Dmytrychenko, Oleg Bilyakovych, Anatoliy Savchuk, Yuliya Turitsa, Aleksandr Milanenko

Abstract: One of the directions in the theory of friction and wear is to study the mechanical and physico-chemical processes occurring in the contact. Chemical activity of the solid surface by mechanical action should be considered in conjunction with the "reverse" influence of physical adsorption and chemical reactions on the course of plastic deformation [1]. In the study of anti-wear properties of the studied oil compositions, a number of common patterns of wear of friction pairs in the area of sliding bearings was found. In order to provide the most appropriate lubrication modes, oil should be characterised by certain operating characteristics meeting requirements imposed on them. Significant is the type and design features of the machines, particularly transmissions, the metal used for the manufacture of gears, type of surface hardening, etc. The most important point is to describe the conditions of local destruction by friction. Undoubtedly, the wear is a much more complex physical and chemical phenomenon than friction because it leads to plastic deformation combined with processes of local destruction of the surface layers of the material.

Keywords: Wear, Wear contact, Surface friction.

 

Corrosion Behaviour of Industrial Metals and Alloys: Electrochemical Studies in Materials Engineering

Joanna LOCH, Halina KRAWIEC

Abstract: Materials engineering uses tools to determine the mechanical, physical, and chemical properties of materials before exploitation. In the engineering design it is very important to estimate the cost of repairing a destroyed structure. The application of electrochemical techniques in the investigation of industrial materials is presented in this work. In addition, described are the problems of corrosion of metals in industrial conditions and corrosion resistance of alloys in simulated solution. Electrochemical test in local scale give a lot of information about the corrosion phenomena occurring on the surface of multiphase alloys and allow to understand better the corrosion processes.

Keywords: Materials engineering, Electrochemistry, Corrosion, Environmental of corrosion.

 

Effect of Welding Parameters on the Properties of Welded Joints Made of Construction Steel

Mykola KORENIVSKYI, Bogdan KUPIEC, Agnieszka JĘDRUSIK

Abstract: The paper presents the results of welded joints of construction steel. The joints were made by means of MMA method. Visual, metallographic, hardness, and thermoelectric power measurements have been performed. Existence of differences in the thermoelectric power and toughness in the weld area has been demonstrated.

Keywords: MMA welding, Construction steel, Metallography, Thermoelectric power.

 

Regeneration of Vehicle Cast Iron Brake Calipers

Bogdan KUPIEC, Mykola KORENIVSKYI, Agnieszka JĘDRUSIK

Abstract: Increasing competitiveness of the market auto parts industry requires the development of methods for their regeneration. Regenerated parts satisfy all the parameters of new parts and their value compared with the rest is lower. The article focuses on and describes an example of repairing vehicle brake calipers made of ductile cast iron which undergo natural wear and tear. Regeneration was made by pad welding with additional material, which was cored wire EnDOtec DO*23 for welding cast iron. Metallographic and hardness examination confirmed the usefulness and accuracy of surfacing to regenerate iron brake calipers used in vehicles.

Keywords: Regeneration, Welding, MAG (136), Brake calipers, Motor vehicles, Grey cast iron, Nodular cast iron.

 

High Temperature Strength of Ceramic Moulds Applied in the Investment Casting Method

Joanna KOLCZYK, Jerzy ZYCH

Abstract: Ceramic casting moulds strength is an important factor which influences the quality and properties of castings being produced by the investment casting method. It is especially important during mould pouring with liquid metal. Studies allowing to determine the casting mould strength at high temperatures, i.e. those at which the moulds are poured, are rather scarce. None generally accepted (normalised) method for the assessment of such strength exists in practice. The new method of the ceramic moulds tensile strength investigation at high temperatures is described in the paper. Tests were performed at temperatures ranging from 100°C to 1100°C. The ceramic moulding sand was prepared of modern materials: colloidal silica – being a binder – and highly refractory ceramic materials.

Keywords: Melted models, Strength, Ceramic forms, Colloid silicate.



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