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Tytuł:
Kinetics of Gases Emission from Surface Layers of Sand Moulds
Autorzy:
Zych, J.
Mocek, J.
Kaźnica, N.
Powiązania:
https://bibliotekanauki.pl/articles/382829.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
moulding sand
surface layer
gases
kinetics of gas emission
chemical binders
piasek formierski
warstwa powierzchniowa
gazy
emisja gazów
środki wiążące
Opis:
Gas emission from casting moulds, cores and coatings applied for sand and permanent moulds is one of the fundamental reasons of casting defects occurrence. In the previous studies, gas emission was measured in two ways: normalized, in which the evolving gas volume was measured during heating of the moulding sand sample in a sealed flask, or by measuring the amount of gas from sand core (sample) which is produced during the pouring of liquid metal. After the pouring process the sand mould is heated very unequally, the most heated areas are layers adjacent to the liquid metal. The emission of gas is significantly larger from the surface layer than from the remaining ones. New, original method of measuring kinetics of gas emission from very thin layers of sand moulds heated by liquid metal developed by the authors is presented in the hereby paper. Description of this new method and the investigation results of kinetics of gas emission from moulding sand with furan and alkyd resin are shown. Liquid grey cast iron and Al-Si alloy were used as a heat source in the sand moulds. Comparison of the kinetics of gas emission of these two kinds of moulding sands filled with two different alloys was made. The momentary metal temperature in sand mould was assigned to the kinetics of gas emission, what creates a full view of the possibility of formation of casting defects of the gaseous origin. Moulding sand with alkyd resin is characterized by larger gas emission; however gases are emitted slower than in the case of moulding sands with furan resin. This new investigation method has a high repeatability and is the only one which gives a full view of phenomenon’s in the surface layer which determines quality of the casings. The obtained results are presented on several graphs and analyzed in detail. They have a great application value and can be used in the production of iron as well as light metal alloy castings.
Źródło:
Archives of Foundry Engineering; 2018, 18, 1; 222-226
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Role of Sand Grains in Sorption Processes by Surface Layers of Components of Sand Moulds
Autorzy:
Kaźnica, N.
Powiązania:
https://bibliotekanauki.pl/articles/383033.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
castings defects
moisture sorption
surface layer
furan moulding sands
sand grains
wady odlewnicze
wilgoć
warstwa powierzchniowa
masa formierska furanowa
furan
Opis:
The results of researches of sorption processes of surface layers of components of sand moulds covered by protective coatings are presented in the hereby paper. Investigations comprised various types of sand grains of moulding sands with furan resin: silica sand, reclaimed sand and calcined in temperature of 700 oC silica sand. Two kinds of alcoholic protective coatings were used – zirconium and zirconium – graphite. Tests were performed under condition of a constant temperature within the range 30 – 35oC and high relative air humidity 75 - 80%. To analyze the role of sand grains in sorption processes quantitavie moisture sorption with use of gravimetric method and ultrasonic method were used in measurements. The tendency to moisture sorption of surface layers of sand moulds according to the different kinds of sand grains was specified. The effectiveness of protective action of coatings from moisture sorption was analyzed as well. Knowledge of the role of sand grains from the viewpoint of capacity for moisture sorption is important due to the surface casting defects occurrence. In particular that are defects of a gaseous origin caused by too high moisture content of moulds, especially in surface layers.
Źródło:
Archives of Foundry Engineering; 2017, 17, 1; 87-92
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effectiveness of Protective Action of Coatings from Moisture Sorption into Surface Layer of Sand Moulds
Autorzy:
Kaźnica, N.
Zych, J.
Powiązania:
https://bibliotekanauki.pl/articles/354937.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
surface layer
furan moulding sands
protective coatings
moisture sorption
Opis:
The results of investigations of the sorption process of surface layers of sand moulds covered by zirconium and zirconium - graphite alcohol coatings are presented in the paper. Investigations comprised two kinds of sand grains (silica sand and reclaimed sand) of moulding sand with furan resin. Tests were performed under conditions of a high relative air humidity 75-85% and a constant temperature within the range 28–33°C. To evaluate the effectiveness of coatings protective action from moisture penetration into surface layers of sand moulds gravimetric method of quantitavie moisture sorption and ultrasonic method were applied in measurements. The optimal number and kind of coatings from the viewpoint of protection from moisture sorption were specified for furan moulding sands with quartz sand and reclaimed sand as well. Knowledge of proper coatings selection is important due to protection from high air humidity and its adverse effects. What is more, it can allow to select the proper storage conditions of casting moulds waiting for being poured with liquid metals. This can limit the occurrence of surface defects which are caused by too high humidity of casting moulds, especially in surface layer.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 4; 2111-2116
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gaseous Atmosphere During Gas Forming Tendency Measurements of the Selected Protective Coatings for Sand Moulds
Autorzy:
Mocek, J.
Powiązania:
https://bibliotekanauki.pl/articles/2079824.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
gas forming
oxygen
hydrogen
carbon monoxide
protective coatings
gaz
tlen
wodór
tlenek węgla
powłoki ochronne
Opis:
Protective coatings have direct contacts with hot and liquid alloys. As the result of such contacts gases are emitted from coatings. Gas forming is a tendency of the tested material to emit gases under a temperature influence. In order to assess the gas forming tendency either direct or indirect methods are applied. In the hereby work, the measurements of the gas forming tendency were performed under laboratory conditions, by means of the developed indirect method. The research material constituted samples of six selected protective coatings dissolved either in alcohol or in water. These coatings are applied in sand moulds and cores for making cast iron castings. The assessment of their gas forming tendency was presented in relation to temperatures and heating times. The occurrence and changes of oxygen and hydrogen contents in gases outflowing from the measuring flask during tests, were measured by means of gas sensors. The process of the carbon monoxide (CO) emission during tests was also assessed. The following gas sensors were installed in flow-through micro chambers: for oxygen - lambda probe, for hydrogen – pellistor, for carbon monoxide - sensor (dedicated for CO) FIGARO TGS 822 TF. The results of direct CO measurements were recalculated according to the algorithm supplied by the producer of this sensor.
Źródło:
Archives of Foundry Engineering; 2021, 21, 3; 11-18
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Assessment of the Permeability of Selected Protective Coatings Used for Sand Moulds and Cores
Autorzy:
Jamrozowicz, Ł.
Siatko, A.
Powiązania:
https://bibliotekanauki.pl/articles/381009.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
permeability
protective coatings
coating viscosity
core
mold
przepuszczalność
powłoki ochronne
lepkość powłoki
rdzeń
forma
Opis:
The article presents the results of permeability measurements of a zirconium alcohol coating applied on moulds and cores. The introduction extensively discusses the reasons for the application of protective coatings, as well as their advantages and disadvantages. Also, the problems related to the application of protective coatings are presented i.e. limited permeability and thus the possibility of the presence of gas-originated defects in the casts. Next, the paper discusses the methods of measuring the permeability of protective coating proposed by Falęcki and Pacyniak. The study also presents an indirect permeability measurement method. For the investigations, zirconium alcohol coatings with the three conventional viscosities 10, 20 and 30s were used. The viscosity was determined by means of the Ford cup with the clearance of 4mm. The coatings were applied onto profiles of Φ 50x50 mm, made of moulding sand consisting of a sand matrix with the mean grain size of dL = 0,11, 17, 24, 31 and 34 mm and phenol-formaldehyde resin. The effect of the matrix grain size on the permeability of the sand with and without a coating was determined.
Źródło:
Archives of Foundry Engineering; 2020, 20, 1; 17-22
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gases Emission From Surface Layers of Sand Moulds and Cores Stored Under the Humid Air Conditions
Autorzy:
Kaźnica, N.
Zych, J.
Mocek, J.
Powiązania:
https://bibliotekanauki.pl/articles/381317.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
surface layer
sand mould
emission of gases
high air humidity
moulding sand
chemical binder
warstwa wierzchnia
forma piaskowa
emisja gazów
wysoka wilgotność powietrza
masa formierska
spoiwo chemiczne
Opis:
A large number of defects of castings made in sand moulds is caused by gases. There are several sources of gases: gases emitted from moulds, cores or protective coatings during pouring and casting solidification; water in moulding sands; moisture adsorbed from surroundings due to atmospheric conditions changes. In investigations of gas volumetric emissions of moulding sands amounts of gases emitted from moulding sand were determined - up to now - in dependence of the applied binders, sand grains, protective coatings or alloys used for moulds pouring. The results of investigating gas volumetric emissions of thin-walled sand cores poured with liquid metal are presented in the hereby paper. They correspond to the surface layer in the mould work part, which is decisive for the surface quality of the obtained castings. In addition, cores were stored under conditions of a high air humidity, where due to large differences in humidity, the moisture - from surroundings - was adsorbed into the surface layer of the sand mould. Due to that, it was possible to asses the influence of the adsorbed moisture on the gas volumetric emission from moulds and cores surface layers by means of the new method of investigating the gas emission kinetics from thin moulding sand layers heated by liquid metal. The results of investigations of kinetics of the gas emission from moulding sands with furan and alkyd resins as well as with hydrated sodium silicate (water glass) are presented. Kinetics of gases emissions from these kinds of moulding sands poured with Al-Si alloy were compared.
Źródło:
Archives of Foundry Engineering; 2017, 17, 4; 79-84
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Humidity Migration in Surface Layers of Sand Moulds During Processes of Penetration and Drying of Protective Coatings
Autorzy:
Jamrozowicz, Łukasz
Zych, Jerzy
Powiązania:
https://bibliotekanauki.pl/articles/2203936.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
surface layers
sand mould
porous medium
humidity migration
protective coatings
resistance measurement
warstwy powierzchniowe
formy piaskowe
migracja wilgoci
powłoki ochronne
pomiar rezystancji
Opis:
The results of investigations of humidity migration in near surface layers of sand mould during processes of penetration and drying of protective coatings are presented in the hereby paper. The process of the humidity exchanging between surroundings and moulding sands as porous materials, is widely described in the introduction. In addition, the humidity flow through porous materials, with dividing this process into stages in dependence of the humidity movement mechanism, is presented. Next the desorption process, it means the humidity removal from porous materials, was described. Elements of the drying process intensity as well as the water transport mechanisms at natural and artificial drying were explained. The innovative research stands for measuring resistance changes of porous media due to humidity migrations was applied in investigations. Aqueous zirconium coatings of two apparent viscosities 10s and 30s were used. Viscosity was determined by means of the Ford cup of a mesh clearance of 4mm. Coatings were deposited on cores made of the moulding sand containing sand matrix, of a mean grain size dL = 0.25 mm, and phenol-formaldehyde resin. Pairs of electrodes were placed in the core at depths: 2, 3, 4, 5, 8, 12 and 16 mm. Resistance measurements were performed in a continuous way. The course of the humidity migration process in the core surface layer after covering it by protective coating was determined during investigations. Investigations were performed in the room where the air temperature was: T = 22 oC but the air humidity was not controlled, as well as in the climatic chamber where the air temperature was: T =35 oC and humidity: H = 45%. During the research, it was shown that the process of penetration (sorption) of moisture into the moulding sand is a gradual process and that the moisture penetrates at least 16 mm into the sand. In the case of the drying (desorption) process, moisture from the near-surface layers of the moulding sand dries out much faster than moisture that has penetrated deeper into the sand.
Źródło:
Archives of Foundry Engineering; 2022, 22, 4; 72--78
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigations of the Sorption Process’ Kinetics of Sand Moulds’ Surface Layers under Conditions of a High Air Humidity
Autorzy:
Kaźnica, N.
Zych, J.
Powiązania:
https://bibliotekanauki.pl/articles/381399.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sand mould
surface layer
moisture sorption
furan moulding sands
alkyd moulding sands
water glass
forma piaskowa
warstwa powierzchniowa
sorpcja wilgoci
furanowa masa formierska
szkło wodne
Opis:
The results of investigations of the sorption process of surface layers of sand moulds under conditions of a high air humidity are presented in the paper. Investigations comprised three kinds of moulding sands with inorganic and organic binders: moulding sand with hydrated sodium silicate with furfuryl resin and with alkyd resin. Tests were performed on the prototype research stand allowing to maintain a constant, high temperature of surroundings (28–33°C) and the relative air humidity (above 95%). The gravimetric method was applied in measurements. The proposed method allows to assess the amount of water which permeates by the area unit of surface layers of sand moulds into their insides. Knowledge of such parameter allows to select the proper storage conditions of casting moulds waiting for being poured with liquid metals. This can limit the occurrence of surface defects which are caused by too high humidity of casting moulds.
Źródło:
Archives of Foundry Engineering; 2015, 15, 3 spec.; 29-32
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Zirconium as an Alloying Additive on the Microstructure and Properties of AlSi9Mg Alloy Cast in Sand Moulds
Autorzy:
Kamińska, Jadwiga
Angrecki, Michał
Dudek, P.
Powiązania:
https://bibliotekanauki.pl/articles/2203930.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
silumins
hardening
alloying additives
microstructure
strength tests
siluminy
utwardzanie
dodatki stopowe
badania mikrostruktury
testy wytrzymałościowe
Opis:
The aim of the study was to select the optimal content of zirconium introduced as an alloying additive to obtain the best strength properties of Al-Si alloy. A technically important disadvantage is the tendency of silumins to form a coarse-grained structure that adversely affects the mechanical properties of castings. To improve the structure, modification processes and alloying additives are used, both of which can effectively refine the structure and thus increase the mechanical properties. According to the Hall-Petch relationship, the finer is the structure, the higher are the mechanical properties of the alloy. The proposed addition of zirconium as an alloying element has a beneficial effect on the structure and properties of silumins, inhibiting the grain growth. The starting material was an aluminium-silicon casting alloy designated as EN AC-AlSi9Mg (AK9). Zirconium (Zr) was added to the alloy in an amount of 0.1%, 0.2%, 0.3%, 0.4% and 0.5% by weight. From the modified alloy, after verification of the chemical composition, samples were cast into sand moulds based on a phenolic resin. The first step in the research was testing the casting properties of alloys with the addition of Zr (castability, density, porosity). In the next step, the effect of zirconium addition on the structure and mechanical properties of castings was determined.
Źródło:
Archives of Foundry Engineering; 2022, 22, 4; 5--13
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza procesu wysychania zawilgoconych warstw wierzchnich form i rdzeni piaskowych na przykładzie masy ze szkłem wodnym
Analysis of the drying process of moistened surface layers of sand moulds and cores on the example of moulding sand with water glass
Autorzy:
Kaźnica, N.
Zych, J.
Kolczyk, J.
Powiązania:
https://bibliotekanauki.pl/articles/391442.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Odlewnictwa
Tematy:
formy piaskowe
warstwy wierzchnie
wysychanie
szkło wodne
sand moulds
surface layers
drying
water glass
Opis:
W pracy przedstawiono analizę procesu wysychania warstw wierzchnich piaskowych form i rdzeni odlewniczych (wykonanych z formierskiej sypkiej masy samoutwardzalnej z uwodnionym krzemianem sodu utwardzanej ciekłym utwardzaczem estrowym) poddanych uprzednio procesowi pochłaniania wilgoci. Po 12-godzinnym procesie sorpcji wilgoci z otoczenia w warunkach wysokiej wilgotności względnej powietrza (powyżej 85%) oraz temperatury (28−33°C) analizowano proces wysychania (desorpcji) powierzchniowych warstw form i rdzeni odlewniczych w warunkach odpowiednio niższych wartości temperatury i wilgotności na przykładzie masy ze szkłem wodnym. W badaniach wykorzystano metodę grawimetryczną. Na podstawie uzyskanych wyników wykazano, że zawilgocone powierzchniowe warstwy wysychają z różną intensywnością, uzależnioną od warunków otoczenia oraz rozmiarów ziarna osnowy piaskowej (porów międzyziarnowych). Wiedza na temat przebiegu zarówno procesu sorpcji, jak i desorpcji wilgoci przez wierzchnie warstwy elementów form piaskowych jest niezbędna do zapobiegania powstawaniu powierzchniowych wad odlewów, pojawiających się okresowo w odlewniach.
An analysis of the drying process of surface layers of sand moulds and cores (made of loose self-hardening moulding sand with hydrated sodium silicate hardened with a liquid ester hardener) which was previously subjected to the process of moisture sorption is presented in the hereby paper. After a 12-hour process of moisture sorption from the environment under conditions of high relative air humidity (over 85%) as well as temperature (28−33°C), an analysis was performed using the drying (desorption) process on the surface layers of sand moulds and cores under conditions of lower values of temperature and humidity on the example of water glass moulding sand. The investigations involved the use of the gravimetric method. Based on the obtained results, it was demonstrated that the moistened surface layers dry up with different intensities depending on the environmental conditions as well as the size of the sand grains (intergranular pores). The knowledge of the course of both the sorption and desorption of moisture by surface layers of sand mould components is necessary to prevent the formation of casting surface defects, which periodically appear in foundries.
Źródło:
Prace Instytutu Odlewnictwa; 2017, 57, 1; 29-38
1899-2439
Pojawia się w:
Prace Instytutu Odlewnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-10 z 24

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