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  1. 88 Archives of Foundry Engineering
  2. 14 Archives of Foundry
  3. 14 Archiwum Odlewnictwa
  4. 12 Zeszyty Naukowe. Mechanika / Politechnika Opolska
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  1. 19 Mochnacki B.
  2. 18 Majchrzak E.
  3. 11 Mendakiewicz J.
  4. 11 Sowa L.
  5. 10 Skrzypczak T.
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  1. 2 2023
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1
Content available Numerical modeling of the solidification process with consideration of shrinkage cavities formation and the influence of solid phase content on the feeding of the casting
Węgrzyn-Skrzypczak Ewa, Skrzypczak Tomasz
Journal of Applied Mathematics and Computational Mechanics
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2023
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Vol. 22, nr 2
75--86
EN
The paper focuses on the numerical modeling of the three-dimensional solidification process of steel using the finite element method (FEM). The model includes and discusses the formation of shrinkage cavities and the influence of the solid phase content on the feeding of the casting through the riser. The analysis assumed a critical value of the solid phase content, at which the transport of liquid phase from the riser to the casting is interrupted. The results of numerical simulation are presented to investigate the influence of this factor on the final quality of the casting. The model neglects the fluid motion in the liquid and solid-liquid regions and replaces the influence of the mold with appropriate boundary conditions.
2
Content available Effect of Inoculation on the Mechanical Properties of AZ91
Rapiejko Cezary, Mikusek D., Kubiak Krzysztof, Pacyniak Tadeusz
Archives of Foundry Engineering
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2023
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Vol. 23, iss. 2
15--20
EN
The effect of Ca element on the microstructure evolution of the AZ91 magnesium alloy was investigated in this research. The magnesium-aluminium alloy AZ91 was inoculated with the Emgesal® Flux 5 to refine its microstructure and also improve its microstructure. Six different concentrations of the Emgesal® Flux 5 content were tested, ranging from 0.1 to 0.6% wt., and compared to the baseline of the AZ91 alloy without inoculation. Melted metal was poured into a preheated metallic mould. Samples to test were achieved after turning treatment. Formed microstructure was assessed using an optical microscope. The microstructure was refined for every tested samples. Mechanical properties such as tensile strength, elongation, Brinell hardness, Vickers microhardness, abrasion resistance and adhesive resistance were tested on the inoculated samples and compared to the non-inoculated AZ91. Introducing an Emgesal®Flux 5 inoculant caused a change in the tensile strength, elongation, Brinell hardness, Vickers microhardness, abrasive wear resistance as well as adhesive wear resistance in each examined concentration.
3
Content available Simulation of Dendrite Morphology and Micro-Segregation in U-Nb Alloy During Solidification
Su Bin, Liu Jing-Yuan, Zhang Xiao-Peng, Yan Xue-Wei
Archives of Metallurgy and Materials
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2022
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Vol. 67, iss. 4
1333--1339
EN
Due to the importance of uranium and uranium alloys to national defence and nuclear industrial applications, it is necessary to understand dendrite formation in their solidification structures and to control their microstructures. In this study, a modified cellular automaton model was developed to predict 2-D and 3-D equiaxed dendrite growth in U-Nb alloys. The model takes into account solute diffusion, preferential growth orientation, interface curvature, etc., and the solid fraction increment is calculated using the local level rule method. Using this model, 2-D large-scale and 3-D equiaxed dendrite growth with various crystallographic orientations in the U-5.5Nb alloy were simulated, and the Nb micro-segregation behaviour during solidification was analysed. The simulated results showed reasonable agreement with the as-cast microstructure observed experimentally.
4
Content available Experimental Verification of the Cast Iron Solidification Model
Mendakiewicz Jerzy
Archives of Foundry Engineering
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2022
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Vol. 22, iss. 3
91--94
EN
The article concerns the experimental verification of the numerical model simulating the solidification and cooling processes proceeding in the domain of cast iron casting. The approximate course of the function describing the evolution of latent heat and the value of substitute specific heat resulting from its course were obtained using the thermal and derivative analysis (TDA) method The TDA was also used to measure the cooling curves at the distinguished points of the casting. The results obtained in this way were compared with the calculated cooling curves at the same points. At the stage of numerical computations, the explicit scheme of the finite difference method was applied. The agreement between the measured and calculated cooling curves is fully satisfactory.
5
Content available Benefit Effect of Low Addition Yttrium on the Phase αMg and eutectic αMg+γ(Mg17Al12) in AZ91 Alloy
Mikusek D., Rapiejko C., Andrzejczak A., Pacyniak T.
Archives of Metallurgy and Materials
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2021
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Vol. 66, iss. 1
57--63
EN
This paper presents results of a study of the effect of inoculation of yttrium on the microstructure of AZ91 alloy. The concentration of the inoculant was increased in samples in the range from 0.1% up to 0.6%. The influence of Y on the thermal effects resulting from the phase transformations occurring during the crystallisation at different inoculant concentrations were examined with the use of Derivative and Thermal Analysis (DTA). The microstructures of the samples were examined with the use of an optical microscope; and an image analysis with a statistical analysis were also carried out. Those analyses aimed at examining oh the effect of inoculation of the Y on the differences between the grain diameters of phase αMg and eutectic αMg+γ(Mg17Al12) in the prepared examined material as well as the average size of each type of grain by way of measuring their perimeters.
6
Content available Structural Characterization of Rapidly Solidified Al71Ni24Fe5 Alloy
Młynarek Katarzyna, Czeppe T., Babilas R.
Archives of Foundry Engineering
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2021
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Vol. 21, iss. 3
90--95
EN
The influence of rapid solidification from the liquid state on the structure of Al71Ni24Fe5 alloy was studied. The samples were prepared by induction melting (ingots) and high pressure die casting into a copper mold (plates). The structure was examined by X-ray diffraction (XRD), light microscopy and high resolution transmission electron microscopy (HRTEM). The mechanism of crystallization was described on the basis of differential scanning calorimetry (DSC) heating and cooling curves, XRD patterns, isothermal section of Al-Ni-Fe alloys at 850°C and binary phase diagram of Al-Ni alloys. The fragmentation of the structure was observed for rapidly solidified alloy in a form of plates. Additionally, the presence of decagonal quasicrystalline phase D-Al70.83Fe9.83Ni19.34 was confirmed by phase analysis of XRD patterns, Fast Fourier Transform (FFT) and Inverse Fast Fourier Transform (IFFT) of transmission electron microscopy images. The metastable character of D-Al70.83Fe9.83Ni19.34 phase was observed because of the lack of thermal effects on the DSC curves. The article indicates the differences with other research works and bring up to date the knowledge about Al71Ni24Fe5 alloys produced by two different cooling rates.
7
Content available Effect of Gadolinium on the Microstructure of Magnesium Alloy AZ91
Rapiejko Cezary, Mikusek D., Just P., Pacyniak T.
Archives of Foundry Engineering
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2021
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Vol. 21, iss. 1
31--36
EN
The paper presents the results of research related to the possibility of inoculation of the AZ91 magnesium alloy casted into ceramic moulds by gadolinium. Effects of gadolinium content (0.1–0.6 wt%) on microstructure of the AZ91 alloy under as-cast state were investigated. The influence of the inoculator on the formation of the microstructure investigated by means of the thermal and derivative analysis by analysing the thermal effects arising during the alloy crystallization resulting from the phases formed. The degree of fragmentation of the microstructure of the tested alloys was assessed by means of the light microscopy studies and an image analysis with statistical analysis was performed. Conducted analyses have aimed at examining on the effect of inoculation of the gadolinium on the differences between the grain diameters and average size of each type of grain by way of measuring their perimeters of all phases, preliminary αMg and eutectics αMg+γ(Mg17Al12) in the prepared examined material.
8
Content available Using of Technology Semisolid Squeeze Casting by Different Initial States of Material
Martinec D., Pastirčák R., Kantoríková E.
Archives of Foundry Engineering
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2020
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Vol. 20, iss. 1
117--121
EN
The paper deals with the effect of heating of various prepared batch materials into semisolid state with subsequent solidification of the cast under pressure. The investigated material was a subeutectic aluminium alloy AlSi7Mg0.3. The heating temperature to the semisolid was chosen at 50% liquid phase. The used material was prepared in a variety of ways: heat treatment, inoculation and by squeeze casting. Also the influence of the initial state of material on inheritance of mechanical properties and microstructure was observed. The pressure was 100 MPa. Effect on the resulting casting structure, alpha phase distribution and eutectic silicon was observed. By using semisolid squeeze casting process the mechanical properties and microstructures of the casts has changed. The final microstructure of the casts is very similar to the microstructure that can be reached by technology of thixocasting. The mechanical properties by using semisolid squeeze casting has been increased except the heat treated material.
9
Content available The Effect of Metal Pouring Conditions on the Formation of Defects in the Casting
Sowa L., Skrzypczak T., Kwiatoń P.
Archives of Foundry Engineering
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2020
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Vol. 20, iss. 2
31--36
EN
The mathematical model and numerical simulations of the solidification of a cylindrical casting, which take into account the process of the mould cavity filling by liquid metal and the feeding of the casting through the conical riser during its solidification, are proposed in the paper. The interdependence of thermal and flow phenomena were taken into account because they have an essential influence on solidification process. The effect of the pouring temperature and pouring velocity of the metal on the solidification kinetics of the casting was determined. In order to obtain the casting without shrinkage defects, an appropriate selection of these parameters was tried, which is important for foundry practice. The velocity fields have been obtained from the solution of Navier-Stokes equations and continuity equation, while temperature fields from solving the equation of heat conductivity containing the convection term. In the solidification modelling the changes in thermo-physical parameters as a function of temperature were considered. The finite element method (FEM) was used to solve the problem.
10
Content available Numerical Model of Solidification Including Formation of Multiple Shrinkage Cavities
Skrzypczak T., Sowa L., Węgrzyn-Skrzypczak E.
Archives of Foundry Engineering
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2020
|
Vol. 20, iss. 1
37--42
EN
Presented paper shows the mathematical and numerical approaches for modelling of binary alloy solidification solved by the Finite Element Method (FEM). The phenomenon of shrinkage cavities formation process is included in the numerical model. Multiple macroscopic cavities can be modelled within the single casting volume. Solid, liquid and gaseous phases with different material properties are taken into account during solidification process. Mathematical model uses the differential equation of heat diffusion. Modification of specific heat is used to describe the heat releasing during liquid-solid phase change. Numerical procedure of shrinkage cavities evolution is based on the recognition of non-connected liquid volumes and local shrinkage computation in the each of them. The recognition is done by the selection of sets of interconnected nodes containing liquid phase in the finite element mesh. Original computer program was developed to perform calculation process. Obtained results of temperature and shrinkage cavities distributions are presented and discussed in details.
11
Content available Intermetallic Phases in Alloyed Cast Iron with 18%Si Addition
Stawarz M.
Archives of Foundry Engineering
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2020
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Vol. 20, iss. 2
37--42
EN
The paper presents an analysis of a selected grade of high silicon cast iron intended for work in corrosive and abrasive conditions. The text describes its microstructure taking into account the process of crystallization, TDA analysis, EDS, XRD and the chemical composition analysis. In order to determine the phase composition, X-ray diffraction tests were carried out. The tests were executed on a Panalytical X'Pert PRO X-ray diffractometer with filtration of radiation from a lamp with copper anode and PIXcel 3D detector on the deflected beam axis. Completed tests allowed to describe the microstructure with detailed consideration of intermetallic phases present in the alloy. Results of the analysis of the examined alloy clearly show that we deal with intermetallic phases of Fe3Si, Fe5Si3 types, as well as silicon ferrite and crystals of silicon. In the examined alloy, we observed the phenomenon of segregation of carbon, which, as a result of this process, enriches the surface of silicon crystals, not creating a compound with it. Moreover, the paper demonstrates capability for crystallization of spheroidal graphite in the examined alloy despite lack of elements that contribute to balling in the charge materials.
12
Content available Influence of Zr on AlSi9Cu1Mg Alloy Cast in Ceramic
Matejka M., Kuriš M., Bolibruchova D., Pastirčák R.
Archives of Foundry Engineering
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2020
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Vol. 20, iss. 2
13--18
EN
The article focuses on the analysis of the effect of Zr on the properties of the aluminium alloy AlSi9Cu1Mg. The effect of Zr was evaluated depending on the change in mechanical properties and heat resistance during a gradual addition of Zr with an increase of 0.05 wt. % Zr. Half of the cast experimental samples from each variant were heat treated by precipitation hardening T6 (hereinafter HT). The measured values in both states indicate an improvement of the mechanical properties, especially in the experimental variants with a content of Zr ≥ 0.20 wt. %. In the evaluation of Rm, the most significant improvement occurred in the experimental variant with an addition of Zr 0.25 wt. % after HT and E in the experimental variant with addition of Zr 0.20 wt. % after HT. Thus, a difference was found from the results of the authors defining the positive effect of Zr, in particular at 0.15 wt. %. When evaluating the microstructure of the AlSi9Cu1Mg alloy after Zr alloying, Zr phases are already eliminated with the addition of Zr 0.10 wt. %. Especially at higher levels of Zr ≥ 0.20 wt. %, long needle phases with slightly cleaved morphology are visible in the metal matrix. It can be stated that a negative manifestation of Zr alloying is expressed by an increase in gassing of experimental alloys, especially in variants with a content of Zr ≥ 0.15 wt. %. Experimental samples were cast into ceramic moulds. The development of an experimental alloy AlSi9Cu1Mg alloyed with Zr would allow the production of a more sophisticated material applicable to thin-walled Al castings capable of operating at higher temperature loads.
13
Content available Examination of the Eutectic Modifying Effect of Sr on an Al-Si-Mg-Cu Alloy Using Various Technological Parameters
Vincze F., Tokár M., Fegyverneki G., Gyarmati G.
Archives of Foundry Engineering
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2020
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Vol. 20, iss. 3
79--84
EN
With the aid of eutectic modification treatment, the precipitation of coarse lamellar eutectic silicon can be suspended during the solidification of aluminum-silicon alloys, thereby the formation of fine-grained, fibrous eutectic Si can be promoted by the addition of small amounts of modifying elements, such as Sr, to the liquid alloy. The effectiveness of this technique is, however, highly dependent on many technological factors, and the degree of modification can be lowered during the various stages of melt preparation due to the oxidation of the Sr-content of the melt. During our research, we investigated the effect of rotary degassing melt treatments coupled with the addition of three different fluxes on the degree of modification of an Al-Si-Mg-Cu casting alloy. It was also studied, that whether additional Sr alloying made before and during the melt treatments can compensate the Sr fading with time. The degree of eutectic modification was characterized by thermal analysis (TA) and the microscopic investigation of TA specimens. It was found, that by using one of the three fluxes, and by adding Sr master alloy rods before the melt treatments, better modification levels could be achieved. It was also found that the measurement of Sr-concentration by optical emission spectroscopy alone cannot be used for controlling the level of eutectic modification.
14
Content available Application of Modular Die for Fluidity Test and Monitoring of the Pressing Force Flow by Semi-solid Squeeze Casting of AlSi7Mg0.3
Martinec D., Pastirčák R.
Archives of Foundry Engineering
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2020
|
Vol. 20, iss. 3
69--73
EN
The fluidity is the term to determine the materials ability to fill the mold cavity properly. Fluidity is complex property with many variables. Up to this date, there is no methodology for defining the fluidity in a semisolid material state. Submitted paper deals with the proposal of a new method designed for aluminium alloy fluidity evaluation in semi-solid state trough the design of the layered construction die. Die will be primary used for fluidity tests of semi-solid squeeze casted aluminium alloy and to observe the pressing force flow by mentioned casting technology. The modularity consists of possibility to change each die segment. In the experiment the die design was evaluated by simulation in ProCAST 11.5 and by production of experimental castings. The die was made by laser cutting technology from construction steel S355JR. Experimental material was aluminium alloy AlSi7Mg0.3. The temperature of the semisolid state was chosen to achieve 35% of solid phase. The result of next study should be a selected parameters observation and their effect on the fluidity of aluminium alloy in semi-solid state. This will be very important step to determine the optimal conditions to achieve a castings with certain wall thickness produced by the method of semi-solid squeeze casting.
15
Content available Effect of Intensive Cooling of Alloy AC-AlSi7Mg with Alloy Additions on Microstructure and Mechanical Properties
Pisarek B., Rapiejko C., Pacyniak T.
Archives of Metallurgy and Materials
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2019
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Vol. 64, iss. 2
677--681
EN
The work presents results of the investigations of effect of intensive cooling of alloy AC-AlSi7Mg with alloy additions on microstructure and mechanical properties of the obtained casts. The experimental casts were made in ceramic molds preliminarily heated to 180°C, into which AC-AlSi7Mg with alloy additions was poured. Within implementation of the research, a comparison was made of the microstructure and mechanical properties of the casts obtained in ceramic molds cooled at ambient temperature and the ones intensively cooled in a cooling liquid. Kinetics and dynamics thermal effects recorded by the TDA method were compared. Metallographic tests were performed with the use of optical microscope and strength properties of the obtained casts were examined: UTS, Elongation and HB hardness.
16
Content available The Influence of Riser Shape on Feeding Effectiveness of Solidifying Casting
Sowa L., Skrzypczak T., Kwiatoń P.
Archives of Foundry Engineering
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2019
|
iss. 4
91--94
EN
The mathematical model and numerical simulations of the solidification of a cylindrical shaped casting, which take into account the process of filling the mould cavity by liquid metal and feeding the casting through the riser during its solidification, are presented in the paper. Mutual dependence of thermal and flow phenomena were taken into account because have an essential influence on solidification process. The effect of the riser shape on the effectiveness of feeding of the solidifying casting was determined. In order to obtain the casting without shrinkage defects, an appropriate selection of riser shape was made, which is important for foundry practice. Numerical calculations of the solidification process of system consisting of the casting and the conical or cylindrical riser were carried out. The velocity fields have been obtained from the solution of momentum equations and continuity equation, while temperature fields from solving the equation of heat conductivity containing the convection term. Changes in thermo-physical parameters as a function of temperature were considered. The finite element method (FEM) was used to solve the problem.
17
Content available Integrated Analytical and Measurement System for the Evaluation of the Properties of Cast Metals and Alloys
Biernat S., Bydałek A. W.
Archives of Foundry Engineering
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2019
|
iss. 1
13--18
EN
The article presents an integrated analytical and measurement system for evaluation of the properties of cast metals and alloys. The presented platform is an extension of the SLAG - PROP application with new modules, which allow to use information on metallurgical processes in an even more effective way, as well as to evaluate the finished product. In addition, the construction of a measuring station for the analysis of thermal processes taking place in a metal bath allows for precise observation of phenomena together with their appropriate interpretation. The article presents not only the cooling curves of certain copper alloys. The analysis also covered mechanical properties related to hardness, finished products depending on the mold in which the products were cast. In the literature one can find information about the mechanical properties of products in the improved state, usually after plastic or thermal treatment, omitting their properties obtained as a result of a naturally made casting. The article also presents the method of placing information in the database using a convenient graphical tool.
18
Content available Influence of Type and Shape of the Chill on Solidification Process of Steel Casting
Jaromin M., Dojka R., Jezierski J. R., Dojka M.
Archives of Foundry Engineering
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2019
|
iss. 1
35--40
EN
The article is a case study of the steel milling ring casting of about 6 tonnes net weight. The casting has been cast in the steel foundry the authors have been cooperating with. The aim was to analyse the influence of the shape of the chills and the material which was used to make them on the casting crystallization process. To optimally design the chills the set of the computer simulation has been carried out with 3 chills’ shape versions and 3 material’s versions and the results have been compared with the technology being in use (no chills). The proposed chills were of different thermal conductivity from low to high. Their shapes were obviously dependant on the adjacent casting surface geometry but were the result of the attempt to optimise their effect with the minimum weight, too. The chills working efficiency was analysed jointly with the previously designed top feeders system. The following parameters have been chosen to compare their effectiveness and the crystallization process: time to complete solidification and so-called fed volume describing the casting feeding efficiency. The computer simulations have been carried out with use of MagmaSoft v. 5.2 software. Finally, the optimisation has led to 15% better steel yield thanks to 60% top feeders weight reduction and 40% shorter solidification time. The steel ring cast with use of such technology fulfil all quality criteria.
19
Content available Effect of Mischmetal on the Microstructure of the Magnesium Alloy AZ91
Mikusek D., Rapiejko C., Walisiak D., Pacyniak T.
Archives of Foundry Engineering
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2019
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iss. 4
45--50
EN
In this paper is discussed the effect of the inoculant mischmetal addition on the microstructure of the magnesium alloy AZ91. The concentration of the inoculant was increased in the samples within the range from 0.1% up to 0.6%. The thermal process was performed with the use of Derivative and Thermal Analysis (DTA). A particular attention was paid to finding the optimal amount of the inoculant, which causes fragmentation of the microstructure. The concentration of each element was verified with use of a spark spectrometer. In addition, the microstructures of every samples were examined with the use of an optical microscope and also was performed an image analysis with a statistical analysis using the NIS - Elements program. The point of those analyses was to examine the differences in the grain diameters of phase αMg and eutectic αMg+γ(Mg17Al12) in the prepared samples as well as the average size of each type of grain by way of measuring their perimeters. This paper is the second part of the introduction into a bigger research on grain refinement of magnesium alloys, especially AZ91. Another purpose of this research is to achieve better microstructure fragmentation of magnesium alloys without the relevant changes of the chemical composition, which should improve the mechanical properties.
20
Content available Effect of Inoculant Emgesal® Flux 5 on the Microstructure of Magnesium Alloy AZ91
Rapiejko C., Mikusek D., Andrzejczak A., Pacyniak T.
Archives of Foundry Engineering
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2019
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iss. 2
15--20
EN
This work presents the results of the research of the effect of the inoculant Emgesal Flux 5 on the microstructure of the magnesium alloy AZ91. The concentration of the inoculant was increased in samples in the range from 0.1% to 0.6%. The thermal processes were examined with the use of Derivative and Thermal Analysis (DTA). During the examination, the DTA samplers were preheated up to 180 °C. A particular attention was paid to finding the optimum amount of inoculant, which would cause fragmentation of the microstructure. The concentration of each element was verified by means of a spark spectrometer. In addition, the microstructures of the samples were examined with the use of an optical microscope, and an image analysis with a statistical analysis using the NIS-Elements program were carried out. Those analyses aimed at examining the differences between the grain diameters of phase αMg and eutectic αMg+γ(Mg17Al12) in the prepared samples as well as the average size of each type of grain by way of measuring their perimeters. This paper is an introduction to a further research of grain refinement in magnesium alloys, especially AZ91. Another purpose of this research is to achieve better micro-structure fragmentation of magnesium alloys without the related changes of the chemical composition, which should improve the mechanical properties.
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