Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 29

Liczba wyników na stronie
first rewind previous Strona / 2 next fast forward last
Wyniki wyszukiwania
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 2 next fast forward last
EN
The ablation casting technology consists in pouring castings in single-use moulds made from the mixture of sand and water-soluble binder. After pouring the mould with liquid metal the mould is destructed (washed out) using a stream of cooling medium, which in this case is water. The process takes place while the casting is still solidifying. The following paper focuses on testing the influence of the modified ablation casting of aluminum alloy on casts properties produced in moulds with hydrated sodium silicate binder. The authors showed that the best kind of moulding sands for Al alloy casting will be those hardened with physical factors – through dehydration. The analysis of literature data and own research have shown that the moulding sand with hydrated sodium silicate hardened by dehydration is characterized by sufficient strength properties for the modified ablation casting of Al alloys. In the paper the use of microwave hardened moulding sands has been proposed. The moulds were prepared in the matrix specially designed for this technology. Two castings from the AlSi7Mg alloy were made; one by traditional gravity casting and the other by gravity casting using ablation. The conducted casts tests showed that the casting made in modified ablation casting technology characterizes by higher mechanical properties than the casting made in traditional casting technology. In both experimental castings the directional solidification was observed, however in casting made by ablation casting, dimensions of dendrites in the structure at appropriate levels were smaller.
EN
The aim of this study is to demonstrate the possibility of using moulding sands based on inorganic binders hardened in a microwave chamber in the technology of ablation casting of aluminium alloys. The essence of the ablation casting technology consists in this that a mould with a water-soluble binder is continuously washed with water immediately after being poured with liquid alloy until its complete erosion takes place. The application of an environmentally friendly inorganic binder improves the ecology of the whole process, while microwave hardening of moulding sands allows moulds to be made from the sand mixture containing only a small amount of binder. The studies described in this article included microwave-hardened sand mixtures containing the addition of selected inorganic binders available on the market. The strength of the sands with selected binders added in an amount of 1.0; 1.5 and 2.0 parts by mass was tested. As a next step, the sand mixtures with the strength optimal for ablation casting technology, i.e. about 1.5 MPa, were selected and tested for the gas forming tendency. In the four selected sand mixtures, changes occurring in the samples during heating were traced. Tests also included mould response to the destructive effect of ablation medium, which consisted in the measurement of time necessary for moulds to disintegrate while washed with water. Tests have shown the possibility of using environmentally friendly, microwave-hardened moulding sands in ablation casting of aluminium alloys.
EN
Increasing demands are imposed on foundries to enforce the manufacture of castings characterized by tight dimensional tolerances, high surface finish and total absence of casting defects. To face these challenges, castings are increasingly made in loose self-hardening sands with furfuryl resin, commonly known as furan sands. In the group of self-hardening sands with synthetic resins, loose self-hardening sands with furfuryl resin enjoy the greatest popularity. The sand mixtures based on furan resins are usually subjected to mechanical reclamation. The consumption of binder and hardener and thus the cost of the sand depend on the quality of reclaim, and mainly on the dust removal degree.The planned tightening of the environmental protection regulations in the EU countries, including limiting the content of free furfuryl alcohol in resins and reducing the emission of furfuryl alcohol, formaldehyde and BTEX compounds at workplaces, necessitated the development of a new generation of eco-friendly furfuryl resins that have recently appeared on the market. The main aim of this article was to determine the effect of reclaim content on the sand parameters, such as bending strength, tensile strength, bench life, gas-forming tendency and loss on ignition. Tests were carried out with reclaim content in the sand mixture varying from 50 to 90%. The reclaim obtained by dry mechanical reclamation was supplied by one of the domestic foundries. The results showed that the highest mechanical properties were obtained in sands containing 60% of the reclaim.
EN
Bentonites and clays are included in the group of drilling fluids materials. The raw materials are mainly clay minerals, which are divided into several groups, like montmorillonite, kaolinite, illite, biotite, muscovite, nontronite, anorthoclase, microcline, sanidine or rutile, differing in chemical composition and crystal lattice structure. Clay minerals have a layered structure forming sheet units. The layers merge into sheets that build up to form the structure of the mineral. The aim of the studies carried out in the ŁUKASIEWICZ Research Network - Foundry Research Institute is to explore the possibility of using minerals coming from Polish deposits. The article outlines the basic properties of hybrid bentonites, which are a mixture of bentonite clay called beidellite, originating from overburden deposits of the Turoszów Mine, and foundry bentonite from one of the Slovak deposits. As part of the physico-chemical tests of minerals, measurements included in the PN-85/H-11003 standard, i.e. montmorillonite content, water content and swelling index, were carried out. Additionally, the loss on ignition and pH chemical reaction were determined. Based on the thermal analysis of raw materials, carried out in the temperature range from 0 to 1000⁰C, changes occurring in these materials during heating, i.e. thermal stability in contact with liquid metal, were determined. Examinations of the sand mixture based on pure clay and bentonite and of the sand mixture based on hybrid bentonites enabled tracing changes in permeability, compressive strength and tensile strength in the transformation zone as well as compactability referred to the clay content in sand mixture. Selected technological and strength parameters of synthetic sands are crucial for the foundry, because they significantly affect the quality of the finished casting. Based on the analysis of the results, the optimal composition of hybrid bentonite was selected.
EN
Ablation casting is a technological process in which the increased cooling rate causes microstructure refinement, resulting in improved mechanical properties of the final product. This technology is particularly suitable for the manufacture of castings with intricate shapes and thin walls. Currently, the ablation casting process is not used in the Polish industry. This article presents the results of strength tests carried out on moulding sands based on hydrated sodium silicate hardened in the Floster S technology, intended for ablation casting of the AlSi7Mg (AK7) aluminium alloy. When testing the bending and tensile strengths of sands, parameters such as binder and hardener content were taken into account. The sand mixtures were tested after 24h hardening at room temperature. The next stage of the study describes the course of the ablation casting process, starting with the manufacture of foundry mould from the selected moulding mixture and ending in tests carried out on the ready casting to check the surface quality, structure and mechanical properties. The results were compared with the parallel results obtained on a casting gravity poured into the sand mould and solidifying in a traditional way at ambient temperature.
EN
The results of testing the strength properties of experimental ceramic materials containing spending moulding sand after initial mechanical reclamation as a material for subsequent layers of the stucco composition were presented. Tests were carried out on spent moulding sands from various foundry technologies, i.e. sand with furfuryl resin and sand with hydrated sodium silicate. The spent, agglomerated moulding sand has undergone a crushing process. Next, the required granular fractions used for individual layers of the stucco material were separated. Ceramic samples, in which the spent moulding sand was a substitute for fresh silica sand in successive layers of the stucco composition, were prepared. As a reference material, identical ceramic samples were used but with all layers made from the fresh silica sand. Samples prepared in this way were used to determine the bending strength of ceramic materials in the temperature range from 20 to 900ºC. The obtained values of the bending strength have demonstrated that spent moulding sand can be used in investment casting with no adverse effect on the strength of ceramic materials.
EN
The aim of this study is to demonstrate the possibility of using moulds made from the environmentally friendly sands with hydrated sodium silicate in modified ablation casting. The ablation casting technology is primarily intended for castings with diversified wall thickness and complex shapes made in sand moulds. The article presents the effect of binder content and hardening time on the bending strength Rgu of moulding sands with binders based on hydrated sodium silicate hardened by microwave technology. The aim of the research was to develop an optimal sand composition that would provide the strength necessary to make a mould capable of withstanding the modified ablation casting process. At the same time, the sand composition should guarantee the susceptibility of the mould to the destructive action of the ablation medium, which in this case is water. Tests have shown that microwave hardening provides satisfactory moulds’ strength properties even at a low binder content in the sand mixture.
PL
Rosnące wymagania odbiorców odlewów dotyczące dokładności wymiarowej oraz chropowatości powierzchni odlewów wymuszają na producentach (odlewniach) stosowanie powłok ochronnych na formy i rdzenie. Celem nanoszenia powłok jest: zabezpieczenie przed przypalaniem się (przywarciem) tworzywa formy do odlewu, zmniejszenie chropowatości powierzchni odlewów, ułatwienie usunięcia odlewu z wnęki formy. W artykule przedstawiono wyniki badań nowej generacji powłok wieloskładnikowych, przeprowadzone zgodnie z polską normą PN-H-11011:1997. Zbadano gęstość badanych powłok, zawartość substancji suchej, wskaźnik sedymentacji oraz ilość wydzielanych przez powłoki gazów. Przeprowadzono również wytopy mające na celu określenie wpływu zastosowanych powłok na jakość powierzchni zewnętrznej odlewów staliwnych.
EN
The increasing requirements of casting users regarding the dimensional accuracy and surface roughness of castings force the manufacturers, i.e. foundries, to use protective coatings on moulds and cores. Coatings are applied in order to protect the casting against the burn-on defects (mould material adhering to the casting surface), to reduce the surface roughness of castings, and to facilitate casting removal from the mould cavity. This paper presents the results of studies of multi-component coatings of the new generation made in accordance with the Polish Standard PN-H-11011:1997. Tests included the density of coatings, the content of dry matter, the sedimentation index and the amount of gas emitted by the coating. Melts were made to determine the impact of coating on the quality of the external surface of steel castings.
EN
The results of mechanical reclamation of waste moulding sands with furfuryl resin and activators of new generation are presented. The aim of the research described in this study was to determine what effect the addition of reclaim obtained in the process of dry mechanical reclamation could have on the properties of furan sands. The sand supplied by one of the domestic foundries was after the initial reclamation subjected to a two-step proper reclamation process. The following tests were carried out on the obtained reclaim: pH, S and N content, loss on ignition and comprehensive sieve analysis. The obtained reclaim was next used as a component of moulding sands with furfuryl resin, wherein it formed 50% and 80% of the base moulding material, respectively. The strength properties of the ready sand mixtures (bending strength Rgu and tensile strength Rm u ) were determined after the hardening time of 0.5, 1, 2, 4 and 24 hours.
EN
The essence of ablation casting technology consists in pouring castings in single-use moulds made from the mixture of sand and a water-soluble binder. After pouring the mould with liquid metal, while the casting is still solidifying, the mould destruction (washing out, erosion) takes place using a stream of cooling medium, which in this case is water. This paper focuses on the selection of moulding sands with hydrated sodium silicate for moulds used in the ablation casting. The research is based on the use of Cordis binder produced by the Hüttenes-Albertus Company. It is a new-generation inorganic binder based on hydrated sodium silicate. Its hardening takes place under the effect of high temperature. As part of the research, loose moulding mixtures based on the silica sand with different content of Cordis binder and special Anorgit additive were prepared. The reference material was sand mixture without the additive. The review of literature data and the results of own studies have shown that moulding sand with hydrated sodium silicate hardened by dehydration is characterized by sufficient strength properties to be used in the ablation casting process. Additionally, at the Foundry Research Institute in Krakow, preliminary semi-industrial tests were carried out on the use of Cordis sand technology in the manufacture of moulds for ablation casting. The possibility to use these sand mixtures has been confirmed in terms of both casting surface quality and sand reclamation.
EN
In the family of iron-based alloys, ductile iron enjoys the highest rate of development, finding application in various industries. Ductile iron or the cast iron with spheroidal graphite can be manufactured by various methods. One of them is the Inmold spheroidization process characterized by different technological solutions, developed mainly to increase the process efficiency. So far, however, none of the solutions has been based on the use of a reactor made outside the casting mould cavity. The method of spheroidization inside the casting mould using a reaction chamber developed at the Foundry Research Institute is an innovative way of cast iron treatment. The innovative character of this method consists in the use of properly designed and manufactured reactor placed in the casting mould cavity. Owing to this solution, the Inmold process can be carried out in moulds with both horizontal and vertical parting plane. The study presents the results of examinations of the microstructure of graphite precipitates and metal matrix of castings after spheroidization carried out by the Inmold process using a reactor and mould with vertical parting plane. Special pattern assembly was made for the tests to reproduce plates with wall thicknesses of 3; 5; 7; 10; 20 and 30 mm. The content of residual magnesium was determined for all tested castings, while for castings of plates with a wall thickness equal to or larger than 10 mm, testing of mechanical properties was additionally performed.
EN
The effectiveness of cast iron spheroidization with FeSiMg master alloy by the traditional method and using a reaction chamber placed in the cavity of foundry mould was compared. The method of cast iron treatment in mould cavity using a reaction chamber is an innovative technology developed by the Foundry Research Institute in Krakow. The effectiveness of the spheroidization process carried out by both methods was checked on a series of test castings. The article also presents the results of metallographic examinations and mechanical testing, including the discussion of magnesium yield and its assimilation rate.
PL
Wzrost zapotrzebowania na produkcję detali odlewanych do form metalowych, szczególnie ze stopów aluminium, wymaga używania rdzeni na osnowie piaskowej w celu dokładnego odwzorowywania często skomplikowanych kształtów detali. Rdzenie wykonywane są na osnowie piasku kwarcowego w znacznej części z mas z żywicami, ale i coraz częściej używane są masy ze spoiwami nieorganicznymi. Oprócz zapewnienia rdzeniom odpowiednich parametrów wytrzymałościowych, powinny się one charakteryzować bardzo dobrą wybijalnością. Dlatego tak istotna jest dokładna i miarodajna ocena tego parametru przy ocenie technologii. Badania własne miały na celu opracowanie zmodernizowanej metody oceny wybijalności rdzeni z form metalowych zgodnie z wytycznymi firmy Nemak, uwzględniając przede wszystkim odlewy ze stopów aluminium. W ramach badań opracowano i wykonano prototyp formy metalowej z miejscem na umieszczenie rdzeni (znormalizowane kształtki ø 50x50 mm) do wykonania prób wybijalności oraz określono warunki przebiegu tej próby technologicznej.
EN
The increasing demand for production of details cast into metal moulds, especially of aluminium alloys, requires using cores made on the sand matrix in order to achieve the accurate reproduction of often complicated shapes of these details. Cores are made on the quartz matrix mainly of the core sands with resins, but more and more often the sands with inorganic binders are also used. Apart from the proper strength parameters, the cores should be characterised by very good knock out property. Therefore the accurate and reliable assessment of this parameter is so essential at the technology assessment. The own investigations were aimed at the development of the modernised method of cores knocking out from metal moulds, according to the requirements of the Nemak Company, taking into account - first of all - the aluminium alloys castings. The prototype of the metal mould with the space for cores placements (normalised shaped elements of ø 50x50 mm) for performing knock out tests were developed as well as conditions for such technological tests were determined.
PL
W pracy przedstawiono wpływ temperatury zalewania (w zakresie od 1420°C do 1330°C, co 30°C) na efekt procesu sferoidyzacji przeprowadzonego metodą inmould, z zastosowaniem komory reakcyjnej. Metoda sferoidyzacji w formie, przy użyciu komory reakcyjnej, jest innowacyjną metodą sferoidyzacji opracowaną w Instytucie Odlewnictwa. Procesy sferoidyzacji i modyfikacji zachodzą jednocześnie podczas wypełnienia wnęki ciekłym metalem. Wyniki przeprowadzonych badań zaprezentowano w postaci mikrostruktur wydzieleń grafitu oraz osnowy metalowej. Podano zmiany składów chemicznych żeliwa po procesie sferoidyzacji, w zależności od zastosowanych temperatur zalewania.
EN
The influence of the pouring temperature (within a range: from 1420°C to 1330°C, every 30°C) on the spheroidisation process, performed by the inmould method with the reaction chamber application, is presented in the paper. The inmould spheroidisation method, performed with the application of the reaction chamber, is the innovatory method developed in the Foundry Research Institute.The spheroidisation and modification processes occur simultaneously during the mould cavity filling with liquid metal. The results of the performed investigations are presented in the form of graphite precipitations and metal matrix microstructures. The changes, after the spheroidisation process, of the cast iron chemical compositions in dependence of the applied pouring temperatures, are given.
EN
Two different spheroidization methods were compared in terms of the effect they may have on gas content (oxygen, nitrogen and hydrogen) in ductile iron castings and process efficiency. Two methods of cast iron treatment were investigated, i.e. spheroidization in the foundry mould using a reaction chamber (reactor) developed by the Foundry Research Institute and, as a reference, the method currently used by foundry shops, i.e. spheroidization in the foundry ladle. The effect of spheroidization process was evaluated on test castings. The results of metallographic examinations and mechanical tests as well as the results of measurements of the oxygen, nitrogen and hydrogen content in cast iron after spheroidizing treatment were presented.
EN
The results of own studies concerning the application of a new additive to the CO2-hardened sodium water glass foundry sands are presented. The new additive, which is a composition of aqueous solutions of modified polyalcohols, has been designated by the symbol “B” and is used as an agent improving the sand knocking out properties. The scope of studies included various mechanical and technological properties of foundry sand mixtures, such as permeability, friability, life cycle of cores and knocking out properties. Two types of water glass with different values of the silica modulus and density, designated as R145 and R150, were tested. Moulding sands used in the tests were made with the additive “B”. For comparison, a reference sand mixture with water glass but without the additive “B” was also prepared.
EN
The aim of the study was to determine the applicability of a new product added to water glass-containing foundry sands hardened with ethylene glycol diacetate. The new additive designated by the symbol "B" is a composition of aqueous solutions of modified polyalcohols, improving the sand knocking out properties. The scope of studies included testing various mechanical and technological properties of foundry sand mixtures, such as permeability, friability, life cycle of cores and knocking out properties. In the technological studies, two types of water glass with different values of the silica modulus and density, designated as R145 and R150, were used. Moulding sands were prepared with the additive "B". For comparison, reference sands with water glass but without the additive "B" were also made. In Part I of the article, the results of studies of the effect of additive "B" on the properties of foundry sands with water glass hardened by CO2 blowing were discussed.
EN
The results of research on the possibility of using a gaseous medium (hot air) as a hardening agent for inorganic binders were discussed, and tests on the reclamation of waste moulding sands were carried out. The research programme also included the use of a modernized test stand for hardening of foundry sands with gaseous agents and a pilot plant for the sand reclamation. Cores made on the test stand were examined for the basic technological properties and were also used in moulds for the trial knocking out of castings. Two types of binders were tested, i.e. a modified water glass designated as Binder A and, for comparison, a reference material which was hydrated sodium silicate R145. The hardener for the sand mixtures was hot air (the dehydration of water glass). Trials of the sand reclamation were carried out in a laboratory pilot plant, installed and operating at the Foundry Research Institute. The obtained reclaim was added in different amounts to the sand mixtures subjected to technological tests. The next step included the manufacture of test moulds, pouring them with aluminium alloy, and knocking out of castings to test the collapsibility of moulds and cores.
PL
W artykule przedstawiono wyniki badań dotyczących możliwości wykorzystania odpadowych mas formierskich ze spoiwami krzemianowymi i geopolimerowymi do wytwarzania autoklawizowanego betonu komórkowego. Duża zawartość krzemionki w zużytych masach formierskich i rdzeniowych jest czynnikiem przemawiającym za przyjęciem takiego rozwiązania technologicznego. Koncepcja pracy obejmowała wykonanie serii mieszanek betonowych, zawierających w swoim składzie odpadową masę formierską, która była wprowadzana do podstawowej mieszaniny surowcowej na zasadzie stopniowej substytucji piasku kwarcowego. Ocenę możliwości utylizacji odpadowych mas odlewniczych przeprowadzono na postawie analizy porównawczej, obejmującej podstawowe właściwości technologiczne dwóch rodzajów materiałów, betonu komórkowego podstawowego, który zawierał w składzie tylko piasek kwarcowy „świeży” oraz betonu komórkowego eksperymentalnego, w którym piasek kwarcowy świeży zastępowano zużytą masą formierską.
EN
The article presents the results of research on the possibilities of utilizing waste moulding sands with silicate and geopolymer binders in the production of autoclaved cellular concrete. The high content of silica in the waste moulding and core sands is a factor in favour of this technological solution. The general idea of the study was to make a series of concrete mixes, which would contain in their composition waste moulding sands, which was then introduced to the basic raw material mixture on the principle of gradually increasing the substitute of fresh silica sand. The possibility of utilization of the waste moulding sand was evaluated based on the results of comparative analysis, covering the main technological properties of the two types of materials, i.e. the base cellular concrete composed of “fresh” silica sand only, and experimental cellular concrete, where fresh silica sand was replaced in different proportions with waste moulding sand.
PL
W artykule przedstawiono wyniki prób i badań przeprowadzonych z różnymi dodatkami do mas formierskich opartych o wodorozpuszczalne spoiwa nieorganiczne do ablacyjnego wybijania. W wyniku przeprowadzonych badań technologicznych i prób stanowiskowych wytypowano skład masy, zapewniającej dobrą jakość odlewów i skuteczne wybijanie form z zastosowaniem chłodzenia ablacyjnego. Opracowany skład masy zapewnia odpowiednio dużą wytrzymałość wykonywanych form i jednocześnie masa ta jest podatna na destrukcyjne działanie medium chłodzącego (wody). Przeprowadzone próby dają zadowalające wyniki i dają nadzieję na możliwość stosowania tej metody w przemyśle.
EN
The article presents the results of tests and studies carried out within the framework of statutory activities on various additives to moulding sands based on water-soluble inorganic binders for ablative knocking out of castings. As a result of technological research and bench tests, the composition of moulding sand providing high quality castings and easy knocking out of moulds combined with ablative cooling was selected. The developed moulding sand composition produces moulds which not only possess the required high strength but are also susceptible to the destructive effect of a cooling medium (water). The results of conducted experiments are satisfactory and raise hope as to further possible use of this method in the industry.
first rewind previous Strona / 2 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.