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Wyszukujesz frazę "Bifilm" wg kryterium: Temat


Wyświetlanie 1-10 z 10
Tytuł:
Effect of Filter Thickness on Reoxidation and Mechanical Properties of Aluminium Alloy AlSi7Mg0.3
Autorzy:
Bruna, M.
Remišová, A.
Sládek, A.
Powiązania:
https://bibliotekanauki.pl/articles/352359.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
bifilm
numerical simulation
reoxidation
mechanical properties
filtration
Opis:
The melt cleaning is an important aspect in the production of high-quality aluminum castings. Specifically inclusions within the melt and an excessively high hydrogen content lead to defects and undesired porosity in the castings. Although it is possible to reduce the amount of hydrogen and oxidic inclusions by purge gas treatment and the use of melting salts, it is impossible toremove oxides (bifilms) created during filling of gating system. Paper deals with the effects of melt quality and the placement of a filter in the filling system on Al-7%Si-Mg alloy mechanical properties. Three different filters were used: (a) rectangular ceramic pressed filter with 3 mm thickness (b) cubical pressed ceramic filter with thickness 10 mm (c) cubical pressed ceramic filter with thickness 22 mm. The results showed that the highest tensile strength values were obtained from the filter with thickness of 22 mm. Numerical simulation analysis of the filling process showed that velocity reduction by filter is the major phenomenon affecting the mechanical properties. Another evaluated aspect during experiments was capability of filters to retain old bifilms. For this purpose multiply remelted alloy was prepared and analyzed. Results showed that filter efficiency increases with decreasing melt quality as a result of possibility to retain "old” bifilms better than small and thin "new” bifilms.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 3; 1100-1106
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Possibilities of Bifilm Amount Reduction in Al Castings by Gating System Design Optimization
Autorzy:
Brůna, Marek
Galčík, M.
Sládek, A.
Martinec, D.
Powiązania:
https://bibliotekanauki.pl/articles/2049727.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
reoxidation
bifilm
gating system
aluminium alloys
mechanical properties
Opis:
Submitted work deals with the possibilities of reducing reoxidation by improved gating system design. The result of the reoxidation is the of furled oxide layers - bifilms. During experimental works, non-pressurized and naturally pressurized gating systems designs were introduced and evaluated. Mechanical properties, fracture area, hot tearing index, bifilm index and EDX analysis were used during evaluation. Paper aim is also to clarify the reoxidation phenomenon by visualization with the aid of ProCAST numerical simulation software. Achieved results clearly confirmed the positive effect of the naturally pressurized gating system, main emphasis needs to focus on finding the proper way to reduce the melt velocity. By using vortex element extension at the end of the runner was achieved positive results in term of reoxidation suppression.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 2; 549-559
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessment of Mechanism of Pore Formation in Directionally Solidified A356 Alloy
Autorzy:
Uludag, M.
Dispinar, D.
Powiązania:
https://bibliotekanauki.pl/articles/380892.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
krzepnięcie kierunkowe
porowatość
ziarna
odlewy
directional solidification
porosity
bifilm index
grain refinement
casting
Opis:
It is well-known that the better the control of the liquid aluminium allows obtaining of better properties. One of the most important defects that is held responsible for lower properties has been the presence of porosity. Porosity has always been associated with the amount of dissolved hydrogen in the liquid. However, it was shown that hydrogen was not the major source but only a contributor the porosity. The most important defect that causes porosity is the presence of bifilms. These defects are surface entrained mainly due to turbulence and uncontrolled melt transfer. In this work, a cylindrical mould was designed (Ø30 x 300 mm) both from sand and die. Moulds were produced both from sand and die. Water cooled copper chill was placed at the bottom of the mould in order to generate a directional solidification. After the melt was prepared, prior to casting of the DC cast samples, reduced pressure test sample was taken to measure the melt quality (i.e. bifilm index). The cast parts were then sectioned into regions and longitudinal and transverse areas were investigated metallographically. Pore size, shape and distribution was measured by image analysis. The formation of porosity was evaluated by means of bifilm content, size and distribution in A356 alloy.
Źródło:
Archives of Foundry Engineering; 2017, 17, 1; 157-162
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evolution of Aluminium Melt Quality of A356 After Several Recycling
Autorzy:
Gursoy, O.
Erzi, E.
Tur, K.
Dispinar, D.
Powiązania:
https://bibliotekanauki.pl/articles/1840918.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
A356
recycling
melt quality
reduce pressure test
bifilm index
recykling
topnienie
próba ciśnieniowa
Opis:
Recyclability is one of the great features of aluminium and its alloys. However, it has been typically considered that the secondary aluminium quality is low and bad. This is only because aluminium is so sensitive to turbulence. Uncontrolled transfer and handling of the liquid aluminium results in formation of double oxide defects known as bifilms. Bifilms are detrimental defects. They form porosity and deteriorate the properties. The detection and quantification of bifilms in liquid aluminium can be carried out by bifilm index measured in millimetres as an indication of melt cleanliness using Reduced Pressure Test (RPT). In this work, recycling efficiency and quality change of A356 alloy with various Ti additions have been investigated. The charge was recycled three times and change in bifilm index and bifilm number was evaluated. It was found that when high amount of Ti grain refiner was added, the melt quality was increased due to sedimentation of bifilms with Ti. When low amount of Ti is added, the melt quality was degraded.
Źródło:
Archives of Foundry Engineering; 2020, 20, 4; 61-66
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Sr and Ti Addition on the Corrosion Behaviour of Al-7Si-0.3Mg Alloy
Autorzy:
Uludag, M.
Kocabas, M.
Dispinar, D.
Cetin, R.
Consever, N.
Powiązania:
https://bibliotekanauki.pl/articles/381519.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
A356 alloy
bifilm index
grain refinement
modification
electrochemical corrosion
stop A356
ziarna
modyfikacja
korozja elektrochemiczna
Opis:
In the present study, the corrosion behaviour of A356 (Al-7Si-0.3Mg) alloy in 3.5% NaCl solution has been evaluated using cyclic/potentiodynamic polarization tests. The alloy was provided in the unmodified form and it was then modified with AlTi5B1 for grain refinement and with AlSr15 for Si modifications. These modifications yield to better mechanical properties. Tensile tests were performed. In addition, bifilm index and SDAS values were calculated and microstructure of the samples was investigated. As a result of the corrosion test, the Ecorr values for all conditions were determined approximately equal, and the samples were pitted rapidly. The degassing of the melt decreased the bifilm index (i.e. higher melt quality) and thereby the corrosion resistance was increased. The lowest corrosion rate was founded at degassing and as-received condition (3.9x10-3 mm/year). However, additive elements do not show the effect which degassing process shows.
Źródło:
Archives of Foundry Engineering; 2017, 17, 2; 125-130
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical Properties and Melt Quality Relationship of Sr-modified Al-12Si Alloy
Autorzy:
Uludağ, M.
Uyaner, M.
Yilmaz, F.
Dişpinar, D.
Powiązania:
https://bibliotekanauki.pl/articles/380647.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminum alloy
silicon alloy
modification
quality of casting
bifilm index
porosity
stop aluminium
stop krzemowy
jakość odlewu
porowatość
Opis:
The formation of oxide film on the surface of aluminium melts, i.e. bifilms, are known to be detrimental when they are incorporated into the cast part. These defects causes premature fractures under stress, or aid porosity formation. In this work, Al-12 Si alloy was used to cast a step mould under two conditions: as-received and degassed. In addition, 10 ppi filters were used in the mould in order to prevent bifilm intrusion into the cast part. Reduced pressure test samples were collected for bifilm index measurements. Samples were machined into standard bars for tensile testing. It was found that there was a good agreement with the bifilm index and mechanical properties.
Źródło:
Archives of Foundry Engineering; 2015, 15, 4; 134-140
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of Fracture Stress with Regard to Porosity in Cast A356 Alloy
Autorzy:
Sahin, H.
Atik, M.
Tezer, F.
Temel, S.
Aydin, O.
Kesen, O.
Gursoy, O.
Dispinar, Derya
Powiązania:
https://bibliotekanauki.pl/articles/2079787.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
A356
casting defects
mechanical properties
porosity
fracture stress
Bifilm
stop A356
wady odlewnicze
właściwości mechaniczne
porowatość
naprężenia
Opis:
Production of the defect-free casting of aluminium alloys is the biggest challenge. Porosity is known to be the most important defect. Therefore, many cast parts are subjected to several non-destructive tests in order to check their acceptability. There are several standards, yet, the acceptance limit of porosity size and distribution may change according to the customer design and requirements. In this work, the aim was targeted to evaluate the effect of size, location, and distribution of pores on the tensile properties of cast A356 alloy. ANSYS software was used to perform stress analysis where the pore sizes were changed between 0.05 mm to 3 mm by 0.05 mm increments. Additionally, pore number was changed from 1 to 5 where they were placed at different locations in the test bar. Finally, bifilms were placed inside the pore at different sizes and orientations. The stress generated along the pores was recorded and compared with the fracture stress of the A356 alloy. It was found that as the bifilm size was getting smaller, their effect on tensile properties was lowered. On the other hand, as bifilms were larger, their orientation became the dominant factor in determining the fracture.
Źródło:
Archives of Foundry Engineering; 2021, 21, 4; 21-28
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quality Evaluation of Remelted A356 Scraps
Autorzy:
Yuksel, C.
Tamer, O.
Erzi, E.
Aybarc, U.
Cubuklusu, E.
Topcuoglu, O.
Cigdem, M.
Dispinar, D.
Powiązania:
https://bibliotekanauki.pl/articles/381854.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminium casting alloy
melt quality
scrap
recycle
mechanical properties
bifilm index
stop aluminium
jakość topienia
wióry
recykling
właściwości mechaniczne
Opis:
A356 is one of the widely used aluminium casting alloy that has been used in both sand and die casting processes. Large amounts of scrap metal can be generated from the runner systems and feeders. In addition, chips are generated in the machined parts. The surface area with regard to weight of chips is so high that it makes these scraps difficult to melt. Although there are several techniques evolved to remedy this problem, yet the problem lies in the quality of the recycled raw material. Since recycling of these scrap is quite important due to the advantages like energy saving and cost reduction in the final product, in this work, the recycling efficiency and casting quality were investigated. Three types of charges were prepared for casting: %100 primary ingot, %100 scrap aluminium and fifty-fifty scrap aluminium and primary ingot mixture were used. Melt quality was determined by calculating bifilm index by using reduced pressure test. Tensile test samples were produced by casting both from sand and die moulds. Relationship between bifilm index and tensile strength were determined as an indication of correlation of melt quality. It was found that untreated chips decrease the casting quality significantly. Therefore, prior to charging the chips into the furnace for melting, a series of cleaning processes has to be used in order to achieve good quality products.
Źródło:
Archives of Foundry Engineering; 2016, 16, 3; 151-156
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Role of Metal Quality and Porosity Formation in Low Pressure Die Casting of A356: Experimental Observations
Autorzy:
Gursoy, O.
Nordmak, A.
Syversten, F.
Colak, M.
Tur, K.
Dispinar, D.
Powiązania:
https://bibliotekanauki.pl/articles/1837851.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
die casting
alloy A356
solidification
LPDC
aluminium
quality of alloy
bifilm
porosity
odlewanie ciśnieniowe
stop A356
krzepnięcie
właściwości stopu
porowatość
Opis:
Porosity is one of the major problems in casting operations and there are several discussions in the literature about the porosity formation in aluminum castings. Bifilms are the defects that are introduced into the melt by turbulence. They can be detected with reduced pressure test and presented numerically by measuring bifilm index. The measure of bifilm index is the sum of total oxide length given in millimeters from the cross-section of reduced pressure test sample solidified under 0.01 MPa. In this work, low pressure die casting (LPDC) unit was built in an attempt to enhance the producibility rate. The unit consists of a pump housing that was placed inside the melt in the melting furnace where the pressure was applied instead of the whole melt surface. It was observed that the melt quality of A356 alloy was deteriorated over time which had led to higher porosity. This was attributed to the increased oxide thickness of the bifilm by the consumption of air in between the folded oxides. A relationship was found between bifilm index and pore formation.
Źródło:
Archives of Foundry Engineering; 2021, 21, 1; 5-10
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Role of Metal Quality and Porosity Formation in Low Pressure Die Casting of A356: Experimental Observations
Autorzy:
Gursoy, O.
Nordmak, A.
Syversten, F.
Colak, M.
Tur, K.
Dispinar, D.
Powiązania:
https://bibliotekanauki.pl/articles/1837813.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
die casting
alloy A356
solidification
LPDC
aluminium
quality of alloy
bifilm
porosity
odlewanie ciśnieniowe
stop A356
krzepnięcie
właściwości stopu
porowatość
Opis:
Porosity is one of the major problems in casting operations and there are several discussions in the literature about the porosity formation in aluminum castings. Bifilms are the defects that are introduced into the melt by turbulence. They can be detected with reduced pressure test and presented numerically by measuring bifilm index. The measure of bifilm index is the sum of total oxide length given in millimeters from the cross-section of reduced pressure test sample solidified under 0.01 MPa. In this work, low pressure die casting (LPDC) unit was built in an attempt to enhance the producibility rate. The unit consists of a pump housing that was placed inside the melt in the melting furnace where the pressure was applied instead of the whole melt surface. It was observed that the melt quality of A356 alloy was deteriorated over time which had led to higher porosity. This was attributed to the increased oxide thickness of the bifilm by the consumption of air in between the folded oxides. A relationship was found between bifilm index and pore formation.
Źródło:
Archives of Foundry Engineering; 2021, 21, 1; 5-10
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-10 z 10

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