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1

Burrs from Cores Produced by Cold-Box- Amine Method and Possibility of their Elimination in Eurocast Košice s.r.o. Company

Vaskova I., Hrubovcakova M.

Archives of Foundry Engineering

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2015

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Vol. 15, iss. 1 spec.

115--120

EN

Foundry industry belongs toward key branch with important meaning for different manufacturing industries. Liquid metal is casting in foundry, which makes cast stock with weight from several grams till several ton [1]. To achieve asking qualities of the product is needed know abundance technological a technical process and progress, but in spite of long – term development foundry industry there occur some question marks, that need answer. Characteristic defect castings of ferrous alloys, which often accompanies the use of amine - Cold box cores are flash gutters. Survey, it was found that 77 % of those surveyed foundries have problems with burrs, 71 % foundries solves this problem (or try to tackle) protivýronkovými ingredients in nuclear and molding compounds , but only 29 % considered their "antivýronkovú" method for successful and favorable.

2

Ecological Binding Material of First Generation

Vasková I., Hrubovčáková M.

Archives of Foundry Engineering

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2014

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Vol. 14, iss. 2

123--128

EN

Bentonite is clay rock, which is created by decomposition of vulcanic glass. It is formed from mixture of clay minerals of smectite group, mainly montmorillonite, beidellite and nontronite. Its typical characteristics is, that when in contact with water, it intensively swells. First who used this term was W.C. Knight in 1887. The rock had been named after town Fort Benton in American state Montana. For its interesting technological properties and whiteness has wide technological use. Bentonite is selectively mined and according to its final use separately modified, which results in high quality product with specific parameters. In the beginning of 21st century belong bentonite moulding mixtures in foundry to always perspective. Mainly increased ratio of ductile cast iron castings production cannot be ensured without the need of quality bentonite. Great area of scope remains to further research of moulding materials, which return also to bentonite producers.

3

Production of castings by patternless process

Pastirčák R., Urgela D., Krivoš E.

Archives of Foundry Engineering

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2012

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Vol. 12, iss. 1

87-92

EN

This paper deals with production of safety inlay for steam locomotive valve by the Patternless Process method. For the moulds creation was used moulding mixtures of II. generation, whereas binder was used a water glass. CNC miller was used for creation of mould cavity. Core was created also by milling into block made of moulding compound. In this article will be presented also making of 3D model, setting of milling tool paths and parameters for milling.

4

Optimising the composition of natural moulding sands including thermal aspects

Kowalski J. S.

Archives of Foundry Engineering

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2011

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Vol. 11, iss. 2

65-68

EN

The paper discusses the problem of the choice of the moulding sand mixture composition in terms of the sand behaviour in contact with molten metal. Studies of high-temperature phenomena make assessment of the sand composition applicability under real operating conditions possible, thus leading to the elimination of sand-originating casting defects. The research was conducted on selected moulding materials included in the composition of traditional moulding sand mixtures without the addition of carbon. The effect of moulding sand composition and moisture content on the linear dilatation and stress-induced allotropic changes of quartz was examined. The analysis of these phenomena was based on 3D charts and maps generated from data collected during the tests.

5

Thermal aspects of temperature transformations in silica sand

Kowalski J. S.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 3

111--114

EN

Problems related with the choice of moulding sand composition considering its behaviour in contact with molten metal were discussed. The investigations of high-temperature phenomena enable moulding sand composition to be evaluated in terms of its applicability under the specific conditions of a foundry shop. It is also possible to eliminate the casting defects related to moulding sand and its properties. The investigations were carried out on selected moulding sands from the family of the traditional carbon-free moulding mixtures. The effect of moulding sand composition and moisture content on the linear dilatation and stress formation caused by an allotropic quartz transformation was determined. The investigated phenomena were analysed on 3D diagrams plotted from the test data. A strong effect of the beta quartz - alpha quartz transformation at a temperature of about 600oC was stated.

6

Physical and chemical clay binder characteristics from various locality and their influence on some technological properties of bentonite mouling mixtures

Vasková I., Fecko D., Malik J., Futáš P.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 1 spec.

211--216

EN

The aim of this paper is to explore the complex physical – chemical characteristics of bentonite of slovak provenance and to compare with non-slovak, which is considered as European highest quality standard in foundry and to compare from the point of foundry application. These characteristics of raw material have direct relationship with technological properties of bentonite sand mixtures and mainly with the quality of castings poured into these mixtures. To compare technological properties of bentonite forming mixtures with use of various clay types point of view application in foundry industry.

7

Tests of moulding mixture by using various clay binder granularity

Vasková I., Malik J., Futáš P.

Archives of Foundry Engineering

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2009

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Vol. 9, iss. 1

29-32

EN

Bentonite as foundry binder has dominant and important significance in Slovak and Czech foundries. Present - day wide world produce of casts is estimated to 80 mil ton. There are about 60-70% casts into bentonite moulding mixtures. We say about mixture of first binder generation where join is results of capillary pressure force and Van der Waals force (forming mixture on the base of bentonite binder). European initions of this technology be included in thirties last century. This technology will have dominant position in spite of formation and development of new manufacturing processes in future. There are these advantages of using moulding mixture on the bentonite base: high value of compression strength and plasticity of this binder is achieved at low content of surface moisture - this fact makes it possible to pour by technology of raw clay, relatively low costs by up to raw material, Cca 95 - 98% repeated usage of moulding mixture, high productivity of used production engineering, high quality of casts (quality surface, uniform accurance, casts without defects) is assured by modern way of ramming, hygienic and ecological advantage.

8

Recykling odpadowych popiołów lotnych powstających ze spalania węgla kamiennego, w aspekcie wytwarzania mas formierskich

Baliński A.

Prace Instytutu Odlewnictwa

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2008

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T. 48, z. 3

5-30

PL

Artykuł stanowi zestawienie ważniejszych wyników badań przeprowadzonych w związku z realizacją projektu badawczego własnego, dotyczącego możliwości zastosowania krajowych popiołów lotnych powstających ze spalania węgla kamiennego, jako osnowy ziarnowej mas formierskich oraz fazy zbrojącej odlewanych kompozytów stopu aluminium (kompozyty ALFA). Przedstawiono skład chemiczny krajowego popiołu lotnego, charakteryzującego się największą stabilnością składu chemicznego (zawartość głównych związków chemicznych - % wag.: SiO2 = 81,66%, Al2O3 = 6,69%, Fe2O3 = 4,37%, CaO = 4,29%, MgO = 1,58%), jego skład fazowy (kwarc, mullit, larnit) oraz charakterystyczne wartości temperatury związane z przemianami fazowymi (temperatura topnienia = 1435°C, temperatura płynięcia = 1494°C, stabilność wymiarowa do temperatury 1230°C). Omówiono badania wpływu zastosowania procesów odmywania i separacji magnetycznej popiołu lotnego na zmiany wartości jego gęstości helowej, powierzchni właściwej, składu chemicznego oraz fazowego. Proces odmywania powoduje istotne zmniejszenie zawartości sodu (o około 20% wag.), a także wapnia (o około 14% wag.) i magnezu (o około 11% wag.), usuniętych głównie z fazy szklistej. Zastosowanie tego procesu powoduje również spadek wartości gęstości rzeczywistej oraz powierzchni właściwej popiołu lotnego. Separacja magnetyczna popiołu lotnego powoduje usunięcie części magnetycznych w ilości około 26% w przeliczeniu na Fe2O3. Towarzyszy temu spadek zawartości glinu, sodu, potasu i wapnia. Procesowi usuwania fazy magnetycznej towarzyszy spadek gęstości rzeczywistej i powierzchni właściwej. Przedstawiono wyniki badań dotyczących aglomeracji popiołu lotnego z zastosowaniem granulatora talerzowego oraz ciśnieniowego. Stwierdzono, że obydwie metody aglomeracji nie umożliwiają uzyskania litego materiału. Uzyskane aglomeraty posiadają strukturę porowatą, jednakże wyraźnie większymi porami charakteryzują się aglomeraty uzyskane w procesie granulacji talerzowej. Badany popiół lotny zastosowano jako osnowę ziarnową do wytwarzania mas formierskich zgodnie z procesem Shawa, procesem termoutwardzalnym (ze szkłem wodnym jako spoiwem) oraz procesem CO2. Określono podstawowe właściwości technologiczne uzyskanych mas formierskich, ich odporność termiczną oraz wytrzymałość resztkową. Stwierdzono przydatność tego rodzaju mas formierskich do wytwarzania form i rdzeni dla odlewów wykonywanych ze stopów metali o temperaturze zalewania nie przekraczającej około 1000°C. Przeprowadzono analizę wpływu zastosowania masy formierskiej z udziałem popiołu lotnego jako osnowy ziarnowej, na skład chemiczny i morfologię granicznej warstwy odlewu ze stopu aluminium. Nie stwierdzono wpływu popiołu lotnego jako osnowy ziarnowej masy formierskiej, na zmianę mikrostruktury oraz morfologii odlewu. Badania możliwości zastosowania popiołu lotnego jako fazy zbrojącej kompozytów ALFA, poprzedzono badaniami właściwości fizykochemicznych osnowy ziarnowej w postaci popiołów lotnych, zużytej w procesie odlewania. Stwierdzono, że pomimo wysokiej reaktywności ciekłego Al i jego stopów w kontakcie z badanym materiałem nie zaobserwowano ich wzajemnego oddziaływania. Po zastosowaniu obróbki cieplnej wytworzonego kompozytu z zastosowaniem popiołu lotnego jako fazy zbrojącej wprowadzonej w ilości 5% wag. oraz materiału wyjściowego w postaci próbek ze stopu aluminium, wytrzymałość R[sub]P02 oraz R[sub]m kompozytu wzrasta o około 10%, w porównaniu do analogicznych wartości materiału wyjściowego. Wartość A5 kompozytu maleje o około 60%, natomiast wartość HBW 5/250 wzrasta o około 55%, w porównaniu do analogicznych wartości materiału wyjściowego.

EN

The article is a compilation of the most important results obtained during execution of own research project regarding the possibility of using fly ash formed during combustion of hard coal as a base granular material in moulding mixtures and as a reinforcing phase in cast aluminium alloy-based composite materials (ALFA composites). The chemical composition of the domestic fly ash, characterised by the greatest stability of composition (the content of the main chemical compounds is the following - wt. %: SiO2 = 81,66%, Al2O3 = 6,69%, Fe2O3 = 4,37%, CaO = 4,29%, MgO = 1,57%), was determined together with the composition of respective phases (quartz, mullite, larnite) and some typical phase transformation-related values of temperature (melting point = 1435°C, flow temperature = 1494°C, dimensional stability up to 1230°C). The effect of washing process and magnetic separation of fly ash on changes in the value of its helium density, specific surface, and chemical and phase composition was discussed. The process of washing decreases significantly the content of sodium (by about 20 wt. %), calcium (by about 14 wt. %) and magnesium (by about 11 wt. %), removed mainly from the glassy phase. Applied effectively, this process also causes a decrease in the value of the fly ash true density and specific surface. Magnetic separation of fly ash removes the magnetic particles in an amount of about 26% in convertion to Fe2O3. A decrease in the content of aluminium, sodium, potassium and calcium usually accompanies this effect. The removal of magnetic phase is accompanied by a drop in the value of true density and specific surface. The article presents the results of investigations regarding the fly ash agglomeration behaviour when conducting the process in a disc granulator and in a pressure granulator. It has been stated that neither of these two methods of agglomeration enables obtaining a truly compact and solid material. The obtained agglomerates are characterised by a porous structure, the agglomerates produced in disc granulators having definitely larger pores. The examined fly ash was used as a base granular material for the manufacture of moulding mixtures used in the Shaw Process, in the process of thermo-setting mixtures (with sodium silicate as a binder), and in mixtures for the CO2 process. The basic technological properties of the manufactured moulding mixtures were determined along with their thermal resistance and residual strength. The applicability of these mixtures in production of foundry moulds and cores for elements cast from metal alloys at temperatures of up to about 1000°C was stated. The effect of the fly ash-based moulding mixture on the chemical composition and morphology of a phase boundary in aluminium alloy casting was analysed. The fly ash used as a base material in foundry mixture was observed to have no effect on changes in casting microstructure and morphology. Investigations of the possibility to use fly ash as a reinforcing phase in ALFA composites were preceded by investigations of the physico-chemical properties of fly ash used as a base material in foundry mixtures after pouring of these mixtures with molten metal. In spite of high reactivity of molten aluminium and its alloys in contact with the examined material, no interaction has been observed to take place. After a heat treatment of the ready, fly ash-containing, composite, where the said fly ash was acting as a reinforcing phase and was introduced in an amount of 5 wt. %, as well as a heat treatment of the base material, i.e. aluminium alloy samples, it was observed that the yield strength R[sub]P02 and tensile strength R[sub]m of the composite increased by about 10%, compared to analogical values obtained for the base, fly ash-free, aluminium alloy. The value of the composite elongation A5 decreased by about 60%, while the value of HBW 5/250 raised by about 55%, compared to analogical values obtained for the base material.

9

Control of cost heftiness of castings production with improvement of PROJECTS

Kafka V., Nykodýmowá V., Szmek V., Lána I., Doupovec D., Knirsch V., Martinák R., Fošum J., Novobílský M., Jochim R.

Archives of Foundry Engineering

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2008

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Vol. 8, iss. 2

77-80

EN

The Specialized Commission for Economy of Czech Foundrymen Society in the Czech Republic systematically follows a solution of particular phases of castings production from iron and non-ferrous metals already for eighth years. These separate studies are uniformly aimed at cost analysis of chosen phases of castings production. The analysis of cost heftiness and recommendations for concrete remedies for particular foundries are the results. The contribution is aimed at transparent description of topics of the PROJECTS I - VII. Further on it describes in more details the PROJECT VIII, especially the costs of preparation of moulding mixtures. The team solving this problem gathers the results of costs comparison of preparation of fifteen moulding mixtures in five Czech foundries in this project. The inquiry topics are bentonite moulding mixtures (unit, pattern, and heap), further on the self-setting mixtures (with waterglass and furane). The inquiry is closed with Cold-Box-Amine core mixture. The evaluation is aimed both at own cost comparison, and at prediction of moulding mixture costs resulting from knowledge of their structure. Further on it deals with the future growth of waste costs. Subsequently, the possibilities of costs specification concerning to power consumption are viewed. Very interesting results are described for studying the relations of costs of moulding mixtures and particular castings. Questions of determining the price of used return moulding mixture are remarkable too. The way to achieve another costs reduction is also the investigation of costs changeableness for mixing the mixtures. The work ends with summary suggestion of next progress.