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1
Content available Computer Simulation of Cast Iron Flow in Castability Trials
Popielarski P., Hajkowski J., Sika R., Ignaszak Z.
Archives of Metallurgy and Materials
|
2019
|
Vol. 64, iss. 4
1433--1439
EN
The paper includes validation studies of the flow module of the NovaFlow&Solid simulation code. Experiments of ductile iron and gray iron casting in a spiral test of castability were carried out. Casting experiments were then carried out in industrial conditions in the Ferrex Foundry in Poznań and the results are the castability spiral length and local cast iron rate during mould cavity pouring. Simulation tests using NovaFlow&Solid Control Volume code were made. The technological castability test was used to determine thermal-physical data through simplified inversion problem. Influence of physical parameters in the database of simulation code on the spiral length obtained as the result of simulation was analyzed. It was found that critical fraction of capillary flow CLF down has the biggest impact on cast iron castability in the simulation code. The simulations resulted in defining parameters of gray iron GJL 250 and ductile iron GJS-400-15. For the parameters set, the length of castability spiral in simulations was in accordance with casting experiments.
2
Content available Cellular Automaton Finite Element Method Applied for Microstructure Prediction of Aluminium Casting Treated by Laser Beam
Hajkowski J., Popielarski P., Ignaszak Z.
Archives of Foundry Engineering
|
2019
|
iss. 3
111--118
EN
What is the limit of improvement the structure obtained directly from the liquid state, with possible heat treatment (supersaturation and aging)? This question was posed by casting engineers who put arbitrary requirements on reducing the DAS (Dendrite Arm Spacing) length to less than a dozen microns. The results of tests related to modification of the surface microstructure of AlSi7Mg alloy casting treated by laser beam and the rapid remelting and solidification of the superficial casting zone, were presented in the paper. The local properties of the surface treated with a laser beam concerns only a thickness ranging from a fraction to a single mm. These local properties should be considered in the aspect of application on surfaces of non-machined castings. Then the excellent surface layer properties can be used. The tests were carried out on the surface of the casting, the surface layer obtained in contact with the metal mould, after the initial machining (several mm), was treated by the laser beam. It turned out that the refinement of the microstructure measured with the DAS value is not available in a different way, i.e. directly by casting. The experimental-simulation validation using the Calcosoft CAFE (Cellular Automaton Finite Element) code was applied.
3
Content available Experimental and Simulation Tests on the Impact of the Conditions of Casting Solidification from AlSi9Cu3 Alloy on their Structure and Mechanical Properties
Hajkowski J., Ignaszak Z.
Archives of Foundry Engineering
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2018
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Vol. 18, iss. 1
167--175
EN
The impact of casting conditions on microstructure a and mechanical properties was described, especially for cast products from AlSi9Cu3 alloy. Particular attention was paid to the parameters of dendritic structure: DAS 1 and DAS 2. Selected mechanical properties (by static tension test) of test castings made using basic technologies of casting: GSC - gravity sand casting, GDC - gravity die-casting and HPDC - high-pressure die-casting, are presented for cast-on test bars and cast separately. Casts were made of the same alloy AlSi9Cu3. Fractures and the zone near the fracture (after static tension test) was subjected to VT - visual tests, PT - penetration tests and metallographic tests. The condition of porosity (fracture zone) was also assessed. The analysis of virtual results was performed using the NovaFlow & Solid system together with the database and they were compared to experimental tests. This way of validation was applied in order to assess the correlation between the local rate of cooling and the size of DAS for GSC, GDC and HPDC technologies. Finally, the correlation between the parameters of structure and mechanical properties with regard to the impact of porosity was signalized.
4
Content available Validation Tests of Prediction Modules of Shrinkage Defects in Cast Iron Sample
Hajkowski J., Roquet P., Khamashta M., Codina E., Ignaszak Z.
Archives of Foundry Engineering
|
2017
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Vol. 17, iss. 1
57--66
EN
The paper presents the results of experimental-simulation tests of expansion-shrinkage phenomena occurring in cast iron castings. The tests were based on the standard test for inspecting the tendency of steel-carbon alloys to create compacted discontinuities of the pipe shrinkage type. The cast alloy was a high-silicone ductile iron of GJS - 600 - 10 grade. The validation regarding correctness of prognoses of the shrinkage defects was applied mostly to the simulation code (system) NovaFlow & Solid CV (NFS CV). The obtained results were referred to the results obtained using the Procast system (macro- and micromodel). The analysis of sensitivity of the modules responsible for predicting the shrinkage discontinuities on selected pre-processing parameters was performed, focusing mostly on critical fractions concerning the feeding flows (mass and capillary) and variation of initial temperature of the alloy in the mould and heat transfer coefficient (HTC) on the casting - chill interface.
5
Content available Methodology of Comparative Validation of Selected Foundry Simulation Codes
Ignaszak Z., Popielarski P., Hajkowski J., Codina E.
Archives of Foundry Engineering
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2015
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Vol. 15, iss. 4
37--44
EN
The validation of each simulation code used in foundry domain requires individual approach due to its specificity. This validation can by elaborated on the basis of experimental results or in particular cases by comparison the simulation results from different codes. The article concerns the influence of grey cast iron density curve and different forms of solid fraction curve Fs=f(T) on the formation of shrinkage discontinuities. Solid fraction curves applying Newtonian Thermal Analysis (NTA) were estimated. The experimental and numerical simulation tests were performed on the castings, which were made with Derivative Thermal Analysis (DerTA) standard cups. The numerical tests were realized using NovaFlow&Solid (NF&S), ProCast and Vulcan codes. In this work, the coupled influence of both curves on the dynamics of the shrinkage-expansion phenomena and on shrinkage defects prognosis in grey cast iron castings has been revealed. The final evaluation of the simulation systems usefulness should be based on validation experiment, preceded by comparing the simulation results of available systems which are proposed in given technology.
6
Content available Contribution to the Identification of Porosity Type in AlSiCu High-Pressure-Die-Castings by Experimental and Virtual Way
Ignaszak Z., Hajkowski J.
Archives of Foundry Engineering
|
2015
|
Vol. 15, iss. 1
143--151
EN
The paper concerns the problem of discontinuity in high pressure die castings (HPDC). The compactness of their structure is not perfect, as it is sometimes believed. The discontinuities present in these castings are the porosity as follow: shrinkage and gas (hydrogen and gas-air occlusions) origin. The mixed gas and shrinkage nature of porosity makes it difficult to identify and indicate the dominant source. The selected parameters of metallurgical quality of AlSi9Cu3 alloy before and after refining and the gravity castings samples (as DI - density index method), were tested and evaluated. This alloy was served to cast the test casting by HPDC method. The penetrating testing (PT) and metallographic study of both kinds of castings were realized. The application of the NF&S simulation system allowed virtually to indicate the porosity zones at risk of a particular type in gravity and high-pressure-die-castings. The comparing of these results with the experiment allowed to conclude about NF&S models validation. The validity of hypotheses concerning the mechanisms of formation and development of porosity in HPDC casting were also analyzed.
7
Content available Examples of new models applied in selected simulation systems with respect to database
Ignaszak Z., Hajkowski J., Popielarski P.
Archives of Foundry Engineering
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2013
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Vol. 13, iss. 1
45--50
EN
The tolerance of damage rule progressively meets the approval in the design casting parts procedures. Therefore, there were appeared the new challenges and expectations for permanent development of process virtualization in the mechanical engineering industry. Virtualization is increasingly developed on the stage of product design and materials technologies optimization. Increasing expectations of design and process engineers regarding the practical effectiveness of applied simulation systems with new proposed up-grades modules is observed. The purpose is to obtain simulation tools allowing the most possible realistic prognosis of the casting structure, including indication, with the highest possible probability, places in the casting that are endangered with the possibility of shrinkage– and gas porosity formation. This 3D map of discontinuities and structure transformed in local mechanical characteristics are used to calculate the local stresses and safety factors. The needs of tolerance of damage and new approach to evaluate the quality of such prognosis must be defined. These problems of validation of new models/modules used to predict the shrinkage– and gas porosity including the chosen structure parameters in the example of AlSi7 alloy are discussed in the paper.
8
Content available Mechanical properties of Al-Si-Mg alloy castings as a function of structure refinement and porosity fraction
Hajkowski M., Bernat Ł., Hajkowski J.
Archives of Foundry Engineering
|
2012
|
Vol. 12, iss. 4
57-64
EN
During design of the casting products technology, an important issue is a possibility of prediction of mechanical properties resulting from the course of the casting solidification process. Frequently there is a need for relations describing mechanical properties of silumin alloys as a function of phase refinement in a structure and a porosity fraction, and relations describing phase refinement in the structure and the porosity fraction as a function of solidification conditions. The study was conducted on castings of a 22 mm thick plate, made of EN AC-AlSi7Mg0,3 alloy in moulds: of quartz sand, of quartz sand with chill and in permanent moulds. On the basis of cooling curves, values of cooling rate in various casting parts were calculated. The paper also presents results of examination of distance between arms in dendrites of a solid solution \alfa (DASL), precipitations length of silicon in an eutectic (DlSi) and gas-shrinkage porosity (Por) as a function of cooling rate. Statistical relations of DASL, DlSi, Por as a function of cooling rate and statistical multiparameter dependencies describing mechanical properties (tensile strength, yield strength, elongation) of alloy as a function of DASL, DlSi and Por are also presented in the paper.
9
Content available remote Sensitivity testing practice on pre-processing parameters in hard and soft coupled modeling
Ignaszak Z., Hajkowski J., Hajkowski M.
Archives of Foundry Engineering
|
2010
|
Vol. 10, iss. 1
51-58
EN
This paper pays attention to the problem of practical applicability of coupled modeling with the use of hard and soft models types and necessity of adapted to that models data base possession. The data base tests results for cylindrical 30 mm diameter casting made of AlSi7Mg alloy were presented. In simulation tests that were applied the Calcosoft system with CAFE (Cellular Automaton Finite Element) module. This module which belongs to "multiphysics" models enables structure prediction of complete casting with division of columnar and equiaxed crystals zones of [alpha]phase. Sensitivity tests of coupled model on the particular values parameters changing were made. On these basis it was determined the relations of CET (columnar-to-equaiaxed transition) zone position influence. The example of virtual structure validation based on real structure with CET zone location and grain size was shown.
10
Międzynarodowe targi poznańskie Innowacje-Technologie-Maszyny ITM Polska
Hajkowski J., Łybacki W.
Przegląd Odlewnictwa
|
2009
|
Vol. 59, nr 7-8
448-453
PL
Tegoroczne Targi Poznańskie odbyły się w dniach 16-19 czerwca 2009 roku, prawie dokładnie w 80 rocznicę Powszechnej Wystawy Krajowej, która dała początek targom o zasięgu międzynarodowym. Obecnie targi ITM Polska, są największymi targami nowoczesnych technologii przemysłowych w nowej Europie. Podział na Salony Tematyczne ułatwia zwiedzającym wybór interesujących dziedzin. Salon Metalurgii, Hutnictwa, Odlewnictwa i Przemysłu Metalowego tzw. METALFORUM jest szczególnie prezentowany przez firmy wiodące w rozwoju nowoczesnych technologii i urządzeń, co daje odlewnikom zapoznanie się z trendami i postępem na polu odlewnictwa. Targi to nie tylko coraz większa liczba wystawców i zwiedzających, ale głównie nawiązywanie kontaktów i dzielenie się swymi osiągnięciami i wiedzą.
EN
The Poznań Fair was hold this year on 16-19 June 2009, almost precisely 80 years after the General Country Exposition, which has given rise to the fairs of international dimension. The ITM Fair Poland is actually the biggest fair devoted to modern industry technologies in the new Europe. The division on the Thematic Salons facilitates to the visitors the choice of the branches they have interest in. The Salon of Metallurgy, Foundry Engineering and Metal Industry, the so called METAL FORUM, is particularly represented by firms leading in developing modern technologies and equipment, what enables to the foundrymen to acquaint themselves with the trends and progress in the scope of foundry technology. The fair - it means not only the greater and greater amount of exhibitors and visitors, but also, principally, establishing of connections and changing the own achievements and knowledge.
11
Content available remote Prediction of useful casting structure applying Cellular Automaton method
Ignaszak Z., Hajkowski J., Hajkowski M.
Archives of Foundry Engineering
|
2009
|
Vol. 9, iss. 3
61-66
EN
The results of simulation investigations of primary casting's structure made of hypoeutectic Al-Si alloy using the Calcosoft system with CAFE 3D (Cellular Automaton Finite Element) module are presented. CAFE 3-D module let to predict the structure formation of complete castings indicating the spatial distribution of columnar and equiaxed grains. That simplified model concerns only hypoeutectic phase. Simulation investigations of structure concern the useful casting of camshaft which solidified in high-insulation mould with properly chills distribution. These conditions let to apply the expedient locally different simplified the grains blocs geometry which are called by the authors as pseudo-crystals. The mechanical properties in selected cross-sections of casing are estimated.
12
Content available remote Impact of cooling time on the structure and tribological properties of metal matrix composite castings
Gawdzińska K., Hajkowski J., Głowacki B.
Archiwum Technologii Maszyn i Automatyzacji
|
2008
|
Vol. 28, nr 3
41-48
EN
The article presents the influence of cooling time on the structure of metal matrix composites (MMC) castings. The examination covered two types of composites manufactured by mechanical mixing. Composite reinforcement consisted of SiC particles, and the matrix consisted of AlSi9 alloy in the first case and AlSill in the second. Comparison covered samples cooled in sand moulds and gravity dies by presenting their cooling curves and their abrasive resistance.
PL
W prezentowanym artykule przedstawiono wpływ szybkości chłodzenia na strukturę odlewów z metalowych materiałów kompozytowych. Badano dwa rodzaje kompozytów wytworzonych metodą mechanicznego mieszania. Zbrojenie kompozytu stanowiły cząstki SiC, osnowę w pierwszym przypadku stop AlSi9, w drugim AlSi11. Porównano materiały chłodzone w formie piaskowej i kokili i przedstawiono ich krzywe krzepnięcia oraz odporność na ścieranie.
13
Content available remote Identification of mould influence on columnar-to-equiaxial-transition zone position in Al-Si alloys castings
Ignaszak Z., Hajkowski J.
Archives of Foundry Engineering
|
2008
|
Vol. 8, iss. 3s
127--133
EN
The course of process validation of CAFE-Calcosoft (ESI-Group) models was presented. It was shown the short description of Cellular Automaton Finite Element (CAFE-3D) method which was applied to system to solidification process identification and to predict the structure of chosen Al-Si alloy. It was determined the sensitivity of thermal model and model to forecast the microstructure on the variability of particular parameters applied to the models taking into consideration the columnar-to-equiaxed transition (CET) zone. The cylindrical casts which solidified in homogenous silica (quartz-Q) sand mould (A) and also in high insulation (HI) mould with chill (B) which coerces high axial temperature gradient, was investigated. The experiment gave the basis to the validation test of CAFE model considering the CET zone which was preceded by two corresponding cases of solidification in respect to thermal conditions of cast-mould system. The virtual structures of studied casts were compared with real structures. It was shown the satisfactory agreement of both structures.
14
Content available remote Struktura i porowatość odlewów ze stopu aluminium a właściwości mechaniczne
Bernat Ł., Hajkowski J., Hajkowski M.
Archiwum Odlewnictwa
|
2006
|
R. 6, nr 22
41-48
PL
W artykule przedstawiono wyniki badań krzywych stygnięcia, kryterium Niyamy, udział porowatości, parametry struktury (odległość między gałęziami w dendrytach i średni kąt nachylenia dendrytów) i właściwości mechanicznych (R_{0,2}, R_{m} i wytrzymałość zmęczeniowa) odlewu płyty ze stopu EN AC-AlSi7Mg krzepnącego w różnych warunkach cieplnych. Określono wpływ kryterium Niyamy na porowatość odlewu oraz wpływ udziału porowatości na właściwości mechaniczne przy niestałych wartościach odległości między gałęziami w dendrytach i średniego kąta nachylenia dendrytów.
EN
In the paper the results of investigations of cooling curves, Niyama criterion, participation of porosity, microstructure parameters (the space between arms in dendrites and mean inclination angle of dendrites) and mechanical properties (R_{0,2}, R_{m} and fatigue strength) of plate casting made of EN AC-A1Si7Mg alloy solidify in different thermal conditions was presented. The influence of Niyama criterion on porosity and participation of porosity on mechanical properties with unstable parameters of spacing between arms in dendńtes and mean inclination angle of dendrites was determined.
15
Content available remote The problems of testing and validation of the cellular automaton-finite element method applied to forecasting a microstructure of hypoeutectic Al-Si alloys
Ignaszak Z., Hajkowski M., Hajkowski J., Popielarski P.
Archiwum Odlewnictwa
|
2005
|
R. 5, nr 15
139--147
EN
The work provides description of odeling with the use of the Cellular Automation-Finite Element Method and its testing, connected with an attempt of validation of the Calcosoft System (CS-CAFE). Results of identification of selected parameters used in stochastic and thermal models are provided, inclusive of determining their effect on the results of forecasting geometric parameters of hypoeutectic Al-Si microstructure alloys. Validation has been carried out with a simulation-experiment method under various conditions of thermal interaction with the casting mould. The results of metallographic studies of structure of specially made castings have been used.
PL
W pracy przedstawiono opis modelowania metodą Cellular Automaton - Finite Element oraz jego testowanie, połączone z próbą walidacji systemu Calcosoft (CS-CAFE). Podano wyniki identyfikacji wybranych parametrów; użytych w modelach stochastycznym i cieplnym; wraz z określeniem ich wpływu na wyniki prognozowania geometrycznych parametrów mikrostruktury podeutektycznego stopu Al-Si. Walidacja została przeprowadzona metodą symulacyjno-eksperymentalną w zróżnicowanych warunkach cieplnych oddziaływania formy odlewniczej. Wykorzystano wyniki metalograficznych badań struktur specjalnie wykonanych odlewów.
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