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Wyświetlanie 1-6 z 6
Tytuł:
Analysis of Inorganic Binder Bridges Destruction after Thermal Load
Autorzy:
Vaskova, I.
Conev, M.
Powiązania:
https://bibliotekanauki.pl/articles/380132.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
inorganic binder
dehydration
alkali silicates
geopolymer
adhesive force
cohesive forces
spoiwo nieorganiczne
odwodnienie
krzemiany alkaliczne
geopolimer
przyczepność
Opis:
Recently, the use of inorganic binders cured by heat as a progressive technology for large scale production of cores is widely discussed topic in aluminium foundries. As practical experiences show, knock-out properties of inorganic binders were significantly increased, although they cannot overcome organic based binder systems. This paper contains information about hot curing processes based on alkali silicate and geopolymer binder systems for core making. Main differences between hot cured geopolymers and hot cured alkali silicate based inorganic binders are discussed. Theory of geopolymer binder states, that binder bridge destruction is mainly of adhesive character. The main aim of this research paper was to examine binder bridge destruction of alkali silicate and geopolymer binder systems. In order to fulfil this objective, sample parts were submitted to defined thermal load, broken and by using SEM analysis, binder bridge destruction mechanism was observed. Results showed that geopolymer binder system examined within this investigation does not have mainly adhesive destruction of binder bridges, however the ratio of adhesive-cohesive to cohesive destruction is higher than by use of alkali silicate based binder systems, therefore better knock-out properties can be expected.
Źródło:
Archives of Foundry Engineering; 2019, 2; 25-28
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of additives in core-forming mixture
Autorzy:
Vasková, I.
Hrubovčáková, M.
Conev, M.
Powiązania:
https://bibliotekanauki.pl/articles/355240.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
innovative foundry technologies and materials
castings defects
additives
Opis:
In recent years, ingredients, also known as additives, which appreciably affect the quality of the casting surface, come to the fore. Additives - lower the temperature at which SiO2 (major component of silica sand) begins to soften and create a melt on the surface of the grains, increase the reactivity and decrease the temperature of a transition to tridimite and cristobalit. These passages support the increase of volume of subsurface sand stress and the tension for the formation of burrs and other casting defects on the surface of the core or the mold. Nowadays, as a great emphasis is put on the quality of the casts, it is therefore necessary to pay attention to these additives, which can effectively reduce the labor intensity in the production of castings and ensure a quality surface of castings.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 1; 335-338
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Technological Properties of Moulding Sands with Geopolymer Binder for Aluminium Casting
Autorzy:
Vaskova, I.
Conev, M.
Hrubovčáková, M.
Powiązania:
https://bibliotekanauki.pl/articles/383257.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
inorganic binder
geopolymer binder
sand core
knock-out properties
aluminium casting
spoiwo nieorganiczne
spoiwo geopolimerowe
masa rdzeniowa
wybijalność masy formierskiej
odlew aluminiowy
Opis:
The use of environmentally friendly inorganic binders and new technologies for cores production is widely discussed topic in recent years. This paper contains information about new hot curing process for core making with alumina-silicate based inorganic binders – geopolymers. Main differences between hot cured geopolymers and hot cured alkali silicate based inorganic binders are discussed. The main objective of this research paper was to investigate basic technological properties of geopolymer binder system such as strength, compaction, storage ability and knock-out properties. For this purpose, three mixtures with different powder additives were prepared and tested in laboratory conditions using specific methods. Strength properties evaluation showed sufficient levels as well as knock-out properties measurement, even with additives B and C originally designed for the use with alkali silicate based two component binder systems. Additives B and C were considered compatible with geopolymer binders after casting production trial results. Storage ability of geopolymers seems to be more sensitive than of alkali silicate based binders in the same tested conditions. Mixtures with geopolymer binder showed 20% more decrease of strength compared to alkali silicate binders after 24 hours in conditions of 25 °C and 65 %RH.
Źródło:
Archives of Foundry Engineering; 2018, 18, 4; 45-49
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of Using Different Types of Risers or Chills on Shrinkage Production for Different Wall Thickness for Material EN-GJS-400-18LT
Autorzy:
Vaskova, I.
Conev, M.
Hrubovcakova, M.
Powiązania:
https://bibliotekanauki.pl/articles/379785.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ductile iron
shrinkage cavity
riser
chill
ultrasound
żeliwo
jama skurczowa
nadlew
Opis:
In modern times there are increasing requirements for products quality in every part of manufacturing industry and in foundry industry it is not different. That is why a lot of foundries are researching, how to effectively produce castings with high quality. This article is dealing with search of the influence of using different types of risers or chills on shrinkage cavity production in ductile iron castings. Differently shaped risers were designed using the Wlodawer´s modulus method and test castings were poured with and without combination of chills. Efficiency of used risers and chills was established by the area of created shrinkage cavity using the ultrasound nondestructive method. There are introduced the production process of test castings and results of ultrasound nondestructive reflective method. The object of this work is to determine an optimal type of riser or chill for given test casting in order to not use overrated risers and thus increase the cost effectiveness of the ductile iron castings production.
Źródło:
Archives of Foundry Engineering; 2017, 17, 2; 131-136
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Decoring Behaviour of Chosen Moulding Materials with Alkali Silicate Based Inorganic Binders
Autorzy:
Conev, M.
Vasková, I.
Hrubovčáková, M.
Hajdúch, P.
Powiązania:
https://bibliotekanauki.pl/articles/356323.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
inorganic binder
alkali silicates
moulding material
knock-out properties
Opis:
This paper contains basic information about new processes for cores for cylinder heads production with alkali silicate based inorganic binders. Inorganic binders are coming back to the foreground due to their ecologically friendly nature and new technologies for cores production and new binder systems were developed. Basically these binder systems are modified alkali silicates and therefore they carry some well-known unfavourable properties with their usage. To compensate these disadvantages, the binder systems are working with additives which are most often in powder form and are added in the moulding material. This paper deals with decoring behaviour of different moulding sands as well as the influence of chosen additives on knock-out properties in laboratory terms. For this purpose, specific methods of specimen production are described. Developed methods are then used to compare decoring behaviour of chosen sands and binder systems.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2A; 703-706
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Opening Material as the Possibility of Elimination Veining in Foundries
Autorzy:
Hrubovčáková, M.
Vaskova, I.
Benkova, M.
Conev, M.
Powiązania:
https://bibliotekanauki.pl/articles/382635.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
molding mixture
cold -box - amine
casting defect
opening material
veining
Opis:
The main bulk density representation in the molding material is opening material, refractory granular material with a particle size of 0.02 mm. It forms a shell molds and cores, and therefore in addition to activating the surface of the grain is one of the most important features angularity and particle size of grains. These last two features specify the porosity and therefore the permeability of the mixture, and thermal dilatation of tension from braking dilation, the thermal conductivity of the mixture and even largely affect the strength of molds and cores, and thus the surface quality of castings. Today foundries, which use the cast iron for produce of casts, are struggling with surface defects on the casts. One of these defects are veining. They can be eliminated in several ways. Veining are foundry defects, which arise as a result of tensions generated at the interface of the mold and metal. This tension also arises due to abrupt thermal expansion of silica sand and is therefore in the development of veining on the surface of casts deal primarily influences and characteristics of the filler material – opening material in the production of iron castings.
Źródło:
Archives of Foundry Engineering; 2016, 16, 3; 157-161
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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