Artykuły (CN-mafe)

Permanent URI for this collectionhttps://repo.agh.edu.pl/handle/AGH/102851

Artykuły czasopisma Metallurgy and Foundry Engineering

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Access status: Open Access ,
A method for taking into account local viscosity changes in single relaxation time the lattice Boltzmann model
(2012) Szucki, Michał; Suchy, Józef Szczepan
The aim of this work is to develop a numerical model, based on the lattice Boltzmann method, which allows for stable stimulation of incompressible fluid flows, including local changes in kinematic viscosity. The authors' interest lies in processes which take place during mould filling. In this publication, general information on the lattice Boltzmann method for two-dimensional single-phase flows were presented. A solution, based on the so called Fractional Step algorithm, which allows for defining kinematic viscosity in each mesh cell individually, was shown. The authors also described in detail a validation procedure for a presented model with the use of commercial simulation environment COMSOL Multiphysics. The results confirmed the correctness of the proposed solution. The presented method can be successfully used for the effective numerical modeling of liquid metal flows inside a casting mould.
Access status: Open Access ,
A voxelization based mesh generation algorithm for numerical models used in foundry engineering
(2012) Szucki, Michał; Suchy, Józef Szczepan
The aim of this study is the adaptation of the voxelization algorithm for the generation of regular computational meshes used in numerical models. The authors concentrate on solutions, which can be applied in a computer modeling of phenomena occurring in the foundry industry. The presented mesh generation process is the STL files based. This file format is generally used in the commercial simulation software. The basic voxelization algorithm extended with such functions as: the input data correctness control (virtual geometry), the formation of meshes consisting of several subdomains corresponding to individual elements of the foundry technology (mould, casting, core, feeder etc.) and the possibility of the mesh local refinement (adaptive grids), is presented in the hereby paper. The described solution is characterized by high efficiency and when combined with the proper numerical model can be successfully implemented in problems related to computer simulation of foundry processes.
Access status: Open Access ,
Al 6082 and Al 7075 alloys under the modified low-cycle fatigue test
(2016) Maj, Maria; Piekło, Jarosław
This paper discusses the possibility of assessing the quality of materials in terms of their mechanical properties as determined by a modified low-cycle fatigue test applied in these studies. The developed computer program adapted to the needs of an MTS universal testing machine is described, as are the details of an algorithm used by this program. The compatibility of test results obtained by the two methods (i.e., the standard low-cycle fatigue test [LCF] and its modified original version [MLCF]) has been demonstrated on the samples of selected non-ferrous metals alloys.
Access status: Open Access ,
AL$_{2}$O$_{3}$-Me layers obtained by the electrochemical method
(2013) Dobosz, Iwona; Uhlemann, Margitta; Gumowska, Wanda
Fine membranes with controlled size of pores were produced by the two step anodizing process of the aluminium in oxalic acid solution. Highly ordered Co, Fe and CoFe nanowire arrays were prepared by two electrodeposition techniques: pulsed (PED) and potentiostatic electrodeposition (DC) into the anodic alumina membrane (AAM) templates. It has been observed that both experimental methods (PED, DC) enable the embedding of Co, Fe as well as CoFe alloy into the pores of the AAM with a high aspect ratio.
Access status: Open Access ,
Allowable strain as an indicator of fatigue life
(2011) Maj, Maria
Fatigue life, allowable strain and different data on the fatigue resistance of metals and alloys are of great importance for the designer. Knowledge of this subject is very important, given the complicated nature of its impact on many factors, starting with the specific properties of different alloys and in the conditions of their operation ending. This is the reason why, in many cases, the aforementioned complex nature of the effect may remain unknown, which can result in too high values of the safety factors adopted in calculations and, conseąuently, in excessive enlargement of the weight of individual parts of the machinery and equipment, especially as regards the cast elements. In this publication to evaluate the effort (fatigue life), the equivalent strain calculated by the aforementioned method directly from the results of the strain measurements was compared with the permissible strain limit, determined from the results of an MLCF fatigue test. Detailed analysis of the obtained results enables us to claim that permissible strain limit can be regarded as an indicator of the fatigue life.
Access status: Open Access ,
Aluminum foams gluing
(2013) Sajek, Adam Eugeniusz
The paper presents an example of design solution of aluminum foam glue joint using two-component epoxy glue. The joint principles for distribution forces and stresses in the tensile sample were formulated. Recommendations for surface preparation of foam and gluing procedure aimed at control the porosity of the foam and glued surface roughness were established. As a result of strength tests defined joint destruction mechanism was proposed. It was suggested that optimized joint design improving its properties.
Access status: Open Access ,
Amorphization and liquid state separation in $Ni_{80-2x}Cu_{x}Fe_{x}P_{20}$ alloys
(2014) Ziewiec, Krzysztof; Prusik, Krystian; Różycka, Mirosława
The aim of the work is to study the ability and potential of glass formation in Ni-Fe-Cu-P alloys. A series of alloys were produced in arc furnace (i.e. $Ni_{70}Fe_{5}Cu_{5}Pe_{20}, Ni_{60}Fe_{10}Cu_{10}P_{20}, Ni_{50}Fe_{15}Cu_{15}P_{20}, Ni_{40}Fe_{20}Cu_{20}P_{20}, Ni_{30}Fe_{25}Cu_{25}P_{20}, Ni_{20}Fe_{30}Cu_{30}P_{20}$). The primary microstructure of the ingots was studied. The ribbons in as-melt-spun state were characterized by X-ray diffraction (XRD). The $Ni_{70}Fe_{5}Cu_{5}P_{5}, Ni_{60}Fe_{10}Cu_{10}P_{20}$ melt-spun alloys were found to be amorphous. For higher copper and iron concentrations a crystalline structure was obtained after melt spinning. This correlated with the tendency for the formation of the Fe-based phases enriched in P and Cu-based poorly alloyed phases which resulted in the formation of crystalline microstructure in melt-spun ribbons. For higher concentration of Fe and Cu, microstructures of the alloys contained constituents resultant from a tendency for separation in the liquid state. It is observed that the formation of the crystal line melt-spun ribbons is caused by the attraction of phosphorus by iron and the formation of copper-based fcc phase.
Access status: Open Access ,
An assessment of the effectiveness of physical curing methods of molding sand bonded by binders based on starch and aluminosilicates
(2015) Kaczmarska, Karolina; Grabowska, Beata; Drożyński, Dariusz; Kurleto, Żaneta; Szymański, Łukasz
In this study, the effectiveness of curing methods by conventional heating and innovative microwave curing were compared, based on the results of determining molding sand selected properties such as permeability, tensile strength, and wear resistance. The tested molding sand used for our research was a composition of silica sand with a commercial binder in the form of Albertine F/1 (Hüttenes Albertus). This binder is a mixture of water-swellable starch derivatives and aluminosilicates. Binding in the molding sand occurred via solvent evaporation from the samples (water).The obtained results showed a dependence of molding sand properties and selected methods of physical cure, especially after one and four hours of cured-sample storage. However, after 24 hours of sample storage (as apparent from the analysis of the obtained results), both curing methods used were almost equally effective, and marked differences in the molding sand properties were located in the range of measurement uncertainty. Using electromagnetic waves in the microwave range made it possible to significantly reduce the time of curing as well as the energy consumption of the drying process.
Access status: Open Access ,
An effect of aromatic diluent addition on the selected properties of epoxy resin
(2005) Hutera, Barbara; Drożyński, Dariusz
The article describes the studies which have been conducted on the dynamic wetting of quartz grains by EPIDIAN 5 resin and by this resin with an addition of 5 wt. %, 20 wt. % and 30 wt. % of xylene at different temperatures. In the case of the investigated resin, the wetting process dynamics is best described by a logarithmic function: theta = A Int + B0, where: theta is the contact angle after time t, and A and B0 are constants characteristic of this process at a given temperature. It has been proved that with 5 wt. % addition of xylene both constants assume a value different than zero. With addition of 20 wt. % and 30 wt. % of xylene, the State of equilibrium is reached almost immediately, and it is expressed by a zero value of constant A. The infrared spectroscopy did not reveal the presence of any chemical reactions between the EPIDIAN 5 resin and xylene, thus confirming that the chemical structure of xylene molecule affects the type of interaction and proves the non-active behaviour of xylene as a diluent. The importance of the studies for foundry sand practice has been stressed.
Access status: Open Access ,
An examination of the heat treatment effect on mechanical properties of twin-roll cast followed by cold rolling sheets made of aluminium and its alloys
(2014) Ściężor, Wojciech; Mamala, Andrzej Jacek; Kwaśniewski, Paweł
Modern aluminium alloys are more commonly used in various industries. Often the products of such materials operate at elevated temperatures. In addition to standard requirements in terms of mechanical and technological properties, one of the key performance properties becomes the increased resistance to annealing. This paper examines the heat treatment effect on the mechanical properties of sheets made of aluminium with grain refiner additions (Ti + B), Fe, Si and Mn. Tested materials were obtained by cold-rolling strips, manufactured by twin-roll casting – TRC method. TRC method is increasingly being used in the manufacture of flat-rolled products. This technology eliminates the hot rolling operations and the strip obtained by TRC method can be subjected to direct cold rolling.
Access status: Open Access ,
An introduction to the problem of the conversion of structural components, including components manufactured by casting techniques
(2016) Czekaj, Edward; Pysz, Stanisław; Garbacz-Klempka, Aldona; Żuczek, Robert
Modern development of technology features not only dynamic changes aimed at improving the performance characteristics of structural components through the optimum selection of materials, adjustments in design, or upgrade of manufacturing processes, but also the increase of the economic impact resulting from these changes. All of these processes occur under one common name of conversion and have a simple or – more often complex character (due to the vast scope of changes introduced). This article examines some basic definitions related to the concept of conversion and its association with innovative and intelligent solutions currently applied in materials engineering. Due to a variety of problems, attention was focused on the core notions related to conversion. Basing on our own experience (i.e., on the experience of the Foundry Research Institute and AGH University of Science and Technology in Krakow) and also on foreign achievements in this particular field of knowledge (mainly coming from the US), the most interesting examples of the conversion of materials and design (in the authors’ opinion) were discussed with reference to the methods of manufacture and possible interactions.
Access status: Open Access ,
Analysis of Clements' method for capability indices estimation
(2009) Czarski, Andrzej
Statistical methods belong to the basic quality tools. Among statistical instruments the statistical process control SPC takes particular place. One of the principal tasks of SPC is process capability analysis i.e. the assessment of process potential as for variability regarding expectations defined by specification limits. This work concerns the comparative analysis of capability indices determination in case of distribution unlike the normal one.
Access status: Open Access ,
Analysis of influence of process parameters on temperature distribution in profiles extruded from 6xxx-series aluminum alloys
(Wydawnictwa AGH, 2018) Berski, Szymon Arkadiusz; Krakowiak, Marlena; Bajor, Teresa; Kawałek, Anna; Jurczak, Henryk
Changing market preferences regarding expectations in terms of the functionality, properties, and appearance of a finished product place excessive demands on manufacturers. The 6xxx-series alloys are the most commonly used in extrusion, and they have broad applications (e.g., the construction, electronics, automotive, and shipbuilding industries). The development of deformation technology at the design stage reaps unquestionable benefits when planning the production process. Under real conditions, the extrusion of hollow profiles requires the use of pocket dies, whose proper design is a complex process. This paper presents the results of preliminary numerical investigations of the extrusion process of structural panels from the 6005A aluminum alloy intended for the construction of transport car bodies. The influence of selected parameters of the extrusion process on the temperature distribution was analyzed in the material. The calculations were made using FEM for a three-dimensional deformation state, taking into account the thermal phenomena occurring during the applied deformation scheme in the extrusion process carried out in a flat die.
Access status: Open Access ,
Analysis of selected technological properties of green sands with starch-based additives
(2015) Drożyński, Dariusz; Kurleto, Żaneta; Kaczmarska, Karolina; Grabowska, Beata
This paper presents the results of determining the effect of the addition of native starch and mineral-starch mixes on selected technological properties of sands. The study was carried out on the permeability, compressive strength, and wear resistance of molding. Green sand with bentonite and silica sand was compared to green sand with the addition of Superior Standard native starch or the addition of a mineral-starch composition in the form of binder Albertine F/1. The main difference in applied starch materials is the characteristic property of native starch which is insoluble in cold water. Therefore, it was difficult to bond water added to molding sand during mixing of the ingredients in this case. However, the Albertine F/1 starch-based binder is a mixture of starch and aluminosilicates, whereas the bonding of water added into molding sand during ingredient mixing is more efficient.
Access status: Open Access ,
Analysis of the effect of $CO_2$ blow on the oxidation of iron alloys' elements
(2012) Karbowniczek, Mirosław; Michaliszyn, Andrzej; Wcisło, Zygmunt; Ślęzak, Wojciech
Reduction of CO$_2$ emission can be achieved in mctallurgical processes. The unit, which has high potential for reducing CO$_2$ emission is a blast fumace, where after the separation of CO$_2$ from the top gas, this gas can be recycled. Gained CO$_2$ can be used in steelmaking processes. The paper shows the results of CO$_2$ blowing into molten metal in order to oxidize carbon and silicon.
Access status: Open Access ,
Analysis of the granulation process mechanism - stand and scope of experimental investigations
(2011) Kamińska, Jadwiga; Dańko, Józef
The paper presents the basic issues related with the post-reclamation dust management by using the technique of agglomeration by granulation. Post reclamation dust derives from different types of molding sands and has different susceptibility for granulation process. Theoretical aspects of granulation are discussed along with the mechanism of this process presented in current literature. Additionally paper describes the experimental test stand for granulation the post reclamation dust and the scope of planned scientific research.
Access status: Open Access ,
Annealing effect on microstructure and chemical composition of Inconel 625 alloy
(Wydawnictwa AGH, 2018) Petrzak, Paweł; Kowalski, Kazimierz; Rozmus-Górnikowska, Magdalena Monika; Dębowska, Aleksandra; Jędrusik, Mateusz; Koclęga, Damian
Our research focused on Inconel 625 weld overlays on 16Mo3 steel boiler pipes. The investigation focused on the characterization of changes in the microstructure and chemical composition after annealing. The annealing was performed for ten hours at temperatures from 600 to 1000°C. Changes in the microstructure were observed with a scanning and transmission electron microscope (SEM and TEM). The investigation was supplemented by hardness measurements.
Access status: Open Access ,
Application of coatings made by plasma spray and PVD methods for protecting graphite molds
(2016) Nejman, Ilona; Richert, Maria Wiesława; Zawadzka, Paulina
The results of our research on the application of coatings for protecting industrial casting molds are presented. Tests were carried out on graphite molds with deposited Al₂O₃ coatings containing the addition of glassy carbon and with W/Zr/DLC coatings, both examined after the process of pouring molds with molten aluminum bronze. The coatings were applied by two different methods; i.e., plasma spraying in the case of Al₂O₃ + glassy carbon coating and PVD in the case of W/Zr/DLC coating. Reference tests were also conducted on graphite molds without coating. The use of protective coatings on graphite molds seems to be an effective solution. Studies have shown that coatings have good resistance during the casting process. The liquid metal sticking to the surface did not penetrate deep inside the graphite mold. The use of coating technology reduces the amount of downtime necessary to replace worn molds and increases the efficiency of the casting process.
Access status: Open Access ,
Application of water equivalents method to calculation of ceramic heat exchangers
(2009) Karczewski, Krzysztof
Application of water equivalents method to calculation of ceramic heat exchangers are presented. By water equivalents method, mathematic model and algorithm of calculation the recuperators made of magnesia shapes were elaborated. By the model, ceramic recuperator to glass melting tank were calculated.
Access status: Open Access ,
Application of water equivalents method to calculation of radiation recuperators with microfinned surface
(2008) Karczewski, Krzysztof
The calculation algorithm by water equivalents method to radiation recuperators with micro-finned surface were elaborated. In this algorithm model research of heat transfer and hydraulic resistance microfinned elements was applied. By elaborated algorithm radiation recuperator with microfinned surface to heat furnace were projected.