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Wyszukujesz frazę "Hajkowski, J." wg kryterium: Autor


Wyświetlanie 1-8 z 8
Tytuł:
Contribution to the Identification of Porosity Type in AlSiCu High-Pressure-Die-Castings by Experimental and Virtual Way
Autorzy:
Ignaszak, Z.
Hajkowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/379466.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Al-Si alloy
gravity
high pressure
die casting
microstructure
gas porosity
shrinkage porosity
virtualization process
complementary model validation
stop Al-Si
odlewanie ciśnieniowe
porowatość gazowa
wirtualizacja
walidacja modelu
Opis:
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.
Źródło:
Archives of Foundry Engineering; 2015, 15, 1; 143-151
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental and Simulation Tests on the Impact of the Conditions of Casting Solidification from AlSi9Cu3 Alloy on their Structure and Mechanical Properties
Autorzy:
Hajkowski, J.
Ignaszak, Z.
Powiązania:
https://bibliotekanauki.pl/articles/380310.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
alloy Al-Si-Cu
casting solidification
casting technologies
microstructure
mechanical properties
stop Al-Si-Cu
krzepnięcie odlewu
technologie odlewania
mikrostruktura
właściwości mechaniczne
Opis:
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.
Źródło:
Archives of Foundry Engineering; 2018, 18, 1; 167-175
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical properties of Al-Si-Mg alloy castings as a function of structure refinement and porosity fraction
Autorzy:
Hajkowski, M.
Bernat, Ł.
Hajkowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/380306.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
właściwości mechaniczne
silumin
szybkość chłodzenia
porowatość
mechanical properties
cooling rate
structure
porosity
Opis:
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.
Źródło:
Archives of Foundry Engineering; 2012, 12, 4; 57-64
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cellular Automaton Finite Element Method Applied for Microstructure Prediction of Aluminium Casting Treated by Laser Beam
Autorzy:
Hajkowski, J.
Popielarski, P.
Ignaszak, Z.
Powiązania:
https://bibliotekanauki.pl/articles/382992.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
microstructure alloys prediction
aluminium alloys
remelting by laser beam
tribology
finite element method applied
cellular automaton
dendrite arm spacing
prognoza mikrostruktury stopów
stopy aluminium
przetapianie wiązką laserową
trybologia
zastosowanie metody elementów skończonych
Opis:
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.
Źródło:
Archives of Foundry Engineering; 2019, 3; 111-118
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Examples of new models applied in selected simulation systems with respect to database
Autorzy:
Ignaszak, Z.
Hajkowski, J.
Popielarski, P.
Powiązania:
https://bibliotekanauki.pl/articles/379975.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
information technology
foundry industry
porosity prediction
structure prediction
database
thermophysical parameters
simulation codes
AlSi alloy
technologia informacyjna
przemysł odlewniczy
przewidywanie struktury
baza danych
parametr termofizyczny
stop Al-Si
Opis:
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.
Źródło:
Archives of Foundry Engineering; 2013, 13, 1; 45-50
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Computer Simulation of Cast Iron Flow in Castability Trials
Autorzy:
Popielarski, P.
Hajkowski, J.
Sika, R.
Ignaszak, Z.
Powiązania:
https://bibliotekanauki.pl/articles/355454.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
application of information technology to the foundry industry
castings defects
cast iron
castability trial
Opis:
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.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 4; 1433-1439
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Methodology of Comparative Validation of Selected Foundry Simulation Codes
Autorzy:
Ignaszak, Z.
Popielarski, P.
Hajkowski, J.
Codina, E.
Powiązania:
https://bibliotekanauki.pl/articles/379771.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
solidification process
castings defect
simulation codes
cast iron
macromodel
micro model
proces krzepnięcia
wada odlewu
żeliwo
model makro
model mikro
Opis:
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.
Źródło:
Archives of Foundry Engineering; 2015, 15, 4; 37-44
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Validation Tests of Prediction Modules of Shrinkage Defects in Cast Iron Sample
Autorzy:
Hajkowski, J.
Roquet, P.
Khamashta, M.
Codina, E.
Ignaszak, Z.
Powiązania:
https://bibliotekanauki.pl/articles/380838.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
castings defects
shrinkage
porosity
ductile cast iron
validation
wady odlewów
porowatość
żeliwo sferoidalne
Opis:
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.
Źródło:
Archives of Foundry Engineering; 2017, 17, 1; 57-66
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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