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1

The influence of benzoyl peroxide on gelation rate of silica binder for precision casting

Nadolski M., Konopka Z., Łągiewka M., Zyska A.

Archives of Foundry Engineering

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2013

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Vol. 13, iss. 2

99--102

EN

Substituting of ethyl silicate with ecologic sols of colloidal silica in the investment casting technology, resulting from the increased demands concerning environmental protection, caused the prolongation of production cycle for precision castings produced in multi-layer thin-walled ceramic shell moulds. Modification of Sizol 030 binder with benzoyl peroxide, proposed in the paper, was aimed at restriction of time needed for realization of a single layer of the shell mould, and by the same, of such a mould as a whole. Examination of kinetics of the drying process were held for the layers made of prepared moulding material and the influence of binder modification on the mould curing time was determined.

2

Determination of heat accumulation coefficient for oil bonded moulding sands

Łągiewka M., Konopka Z., Zyska A., Nadolski M.

Archives of Foundry Engineering

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2013

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Vol. 13, iss. 2

91--94

EN

The possibility of controlling the solidification and cooling time of castings creates prospects of improving their structure and by the same their properties. Thermal properties of the mould constitute therefore an important factor which is necessary to consider while seeking for the mentioned improvement. The presented work illustrates the method of determining some basic thermal coefficients of moulding material, i.e. the coefficient of temperature equalisation a2, known also as the temperature diffusivity, and the heat accumulation coefficient b2, which characterises the ability of moulding material to draw away the heat from a casting. The method consists in experimental determining the temperature field within the mould during the processes of pouring, solidification and cooling of the casting. The performed measurements allow for convenient and exact calculations of the sought-after coefficients. Examinations were performed for the oil bonded moulding sand of trade name OBB SAND ‘E’. The experiment showed that the obtained value of b2 coefficient differs from the value calculated on the basis of theoretical considerations available in publications. Therefore it can be stated that theoretical calculations of the heat accumulation coefficient are thus far not sufficient and not quite reliable, so that these calculations should be verified experimentally.

3

Pochłanianie mikrofal przez zużyte masy formierskie i rdzeniowe

Nowak D., Stachowicz M., Granat K., Pigiel M.

Archives of Foundry Engineering

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2012

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Vol. 12, iss. 1s

149--152

PL

W pracy zaprezentowano wyniki badań pomiaru współczynnika fali stojącej dla oceny skuteczności pochłaniania mikrofal przez zużyte masy formierskie i rdzeniowe wytypowane do przeprowadzenia z ich udziałem procesu mikrofalowej utylizacji. Badania pochłaniania mikrofal zostały przeprowadzone z wykorzystaniem prototypowego stanowiska mikrofalowej linii szczelinowej. Badaniom poddano pięć zużytych mas formierskich i rdzeniowych. Wykazano, że uzyskane wyniki pochłaniania mikrofal mas formierskich i rdzeniowych daje podstawy do przeprowadzenia z ich udziałem procesu mikrofalowej utylizacji.

EN

The paper presents measurement results of standing wave ratio to be used as an efficiency indicator of microwave absorption by used moulding and core sands chosen for the microwave utilization process. The absorption measurements were made using a prototype stand of microwave slot line. Examined were five used moulding and core sands. It was demonstrated that the microwave absorption measurements can make grounds for actual microwave utilization of moulding and core sands.

4

Microwave absorption by used moulding and core sands

Nowak D., Stachowicz M., Granat K., Pigiel M.

Archives of Foundry Engineering

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2012

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Vol. 12, iss. 3

87-90

EN

The paper presents measurement results of standing wave ratio to be used as an efficiency indicator of microwave absorption by used moulding and core sands chosen for the microwave utilization process. The absorption measurements were made using a prototype stand of microwave slot line. Examined were five used moulding and core sands. It was demonstrated that the microwave absorption measurements can make grounds for actual microwave utilization of moulding and core sands.

5

Bell founding – the past and the present

Cebulak M., Kowalski J. S., Wojciechowski W.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 3

167--170

EN

This paper outlines the history of bell founding. The exceptional character of bells, which are products of supracultural importance, was stressed. The complexity of the bell manufacturing process and a unique approach to the technology design were highlighted. Basing on the data obtained from foundry shops currently operating in Poland, known as bell-casting foundries, the main guidelines for the bellcasting process as used nowadays by the Felczyński Foundry with long-standing traditions and Wojdak’s Foundry, both of which are casting bells according to modern technologies, using modern moulding materials and metal alloys, were described.

6

The influence of ceramic fibre on thermal expansion of moulding materials for investment casting technology

Nadolski M., Konopka Z., Łągiewka M., Zyska A.

Archives of Foundry Engineering

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2009

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Vol. 9, iss. 2

147-150

EN

The results of dilatometric measurements presented in the paper are a supplement to the investigations concerning broadening the composition of ceramic slurry intended for investment casting technology with ceramic fibre matrix. An applying of fibre material and a change of rheologic characteristics of ceramic slurry have impelled to develop the method of applying the material to the pattern sets. The technology of multi-layer spraying has been found to be the most favourable method. Partial replacing of the grain silica materials with aluminosilicate materials in the fibrous form has affected the magnitude of dimensional changes taking place during the heating process. In order to determine the magnitude of these changes, there have been prepared slurries of various fibre fraction in the matrix and their thermal expansion has been examined within the temperature range of 273-1273 K.

7

The influence of Cerafiber 10 ceramic fibre on strength properties of moulding material for investment casting technology

Nadolski M., Konopka Z., Łągiewka M., Zyska A., Chojnacki A.

Archives of Foundry Engineering

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2009

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Vol. 9, iss. 4

165-168

EN

The presented investigations have been aimed to determine strength properties of shell ceramic moulds produced on the basis of silica sol with the matrix composed of MK75 silica flour and Cerafiber 10 aluminosilicate ceramic fibre, the chemical composition of the latter being 56% SiO2 and 44% Al2O3. The sample material has been obtained by multi-layer spraying of ceramic slurry onto the pattern sets. The achieved results, concerning strength properties revealed during the controlled bending test performed by means of the four-point deflectometer, have been compared with the presented elsewhere results [16-19] for moulding material with grain or grain-fibre matrix, where TC E08 fibre produced by Thermal Ceramics (i.e. Kaowool HP-50-E-08 fibre) has been applied as a matrix component.

8

Examining of slurries and production of moulds by spraying method in lost wax technology

Nadolski M., Konopka Z., Łągiewka M., Zyska A.

Archives of Foundry Engineering

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2008

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Vol. 8, iss. 2

107-110

EN

The work presents the results of investigation centred around the selection of a ceramic slurry composition if ceramic fibre is applied as a component of moulding material used for the lost wax technology. Producing a ceramic material of assumed parameters demands for changing the surface properties of the mineral grains. The critical concentration of solid particles or the gel point depends on the size of mineral particles, their shape and ability to aggregate. This ability has been achieved by modifying their surface properties by adding some polymer and the wetting agent (surfactant), which are adsorbed. Using the fibre material has required developing a method of its applying to the pattern set. The technology of multi-layer spraying has been recognised as the most advantageous one. The performed laboratory experiments have allowed for determining both the material composition and the parameters of its applying, such as air pressure, nozzle diameter, and the spraying distance for gravity pneumatic spraying gun.

9

Ulepszony - poliuretanowy proces cold-box - korzystny pod względem ekologicznym

Serghini A., Bieda S.

Przegląd Odlewnictwa

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2003

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Vol. 53, nr 7-8

224-230

PL

W artykule przedstawiono działania i wyniki badań laboratoryjnych i przemysłowych, mających na celu ulepszenie poliuretanowego procesu cold-box. Proces poliuretanowy, umożliwiający szybkie uzyskiwanie rdzeni o dużej wytrzymałości, ma również mankamenty, które wymagały usunięcia lub, co najmniej, ograniczenia. Do mankamentów tych można zaliczyć, oprócz emisji substancji toksycznych, zapachu (odoru) i dymu, zbyt dużą wartość indeksu fenolowego oraz kondensację produktów pirolizy. Wprowadzane ulepszenia powodowały stopniową eliminację lub ograniczanie tych mankamentów i powstawanie kolejnych odmian poliuretanowego procesu cold-box, nazwanych w artykule generacjami. W 1. generacji zastąpiono rozpuszczalniki aromatyczne, dodawane do żywicy i poliizocyjanianu, olejemrzepakowym, co spowodowało zmniejszenie emisji substancj i toksycznych. Modyfikacjątej generacji było zastosowanie, jako rozpuszczalnika, estru metylowego kwasu tłuszczowego (2. generacja). W 3. generacji zredukowano zawartość wolnego fenolu w żywicy, co spowodowało znaczne zmniejszenie wartości indeksu fenolowego, ważnego wskaźnika przy ocenie możliwości wykorzystania masy zużytej. Ostatnim osiągnięciem było zastosowanie krzemianu etylujako rozpuszczalnika składników spoiwa (4. generacja). Jakość, toksyczność, wydzielanie zapachu oraz indeks fenolowy mas, uzyskiwanych przy stosowaniu poszczególnych odmian poliuretanowego procesu cold-box, zostały potwierdzone wynikami badań laboratoryjnych i/lub przemysłowych, które wykazały wyraźne stopniowe polepszanie procesu w stosunku do metody wyjściowej. Stwierdzono bowiem wyraźne zmniejszenie (o ok. 65-75%) stężenia wydzielanych substancji toksycznych, takich jak: benzen, toluen i ksylen. Wyraźnie została zmniejszona emisja zapa-chu oraz dymu, szczególnie po zastosowaniu krzemianu etylu jako rozpuszczalnika składników spoiwa. Ten nowy rozpuszczalnik spowodował także ograniczenie skłonności do kondensacji produktów pirolizy spoiwa. Zmniejszenie indeksu fenolowego (wg niemieckich przepisów LAGA) ułatwia gospodarkę materiałami formierskimi w odlewni, w zakresie możliwości wykorzystywania masy zużytej. Te korzystne zmiany mają istotne znaczenie praktyczne, gdyż obecnie ok. 50 % rdzeni wykonuje się metodą cold-box i stosowanie zmodyfikowanych odmian poliuretanowego procesu cold-box polepsza wyraźnie warunki pracy pod względem ochrony środowiska, higieny pracy i gospodarki materiałami formierskimi w odlewni.

EN

In the article the activities and results of laboratory and industrial tests, aiming at the improvement of the polyurethane cold-box process have been described. The polyurethane process, which enables quick fabrication of high-strength cores, has also some disadvantages which should be removed or at least limited. To these disadvantages can be included, besides the emission of toxic substances, also their odour and fumes, too high value of phenol index and condensation of the pyrolysis products. The improvements, which were being introduced, caused gradual elimination or reduction of these disadvantages and the development of new variants of polyurethane cold-box process, called in the article "generations", was continued. In the first generation the aromatic solutions added to the resin and polyisocyanate were substituted by rape oil, what caused a reduction of the emission of toxic substances. A modification in this generation was using, as solution, methyl ester of the fatty acid (the second generation). In the third generation the content of free phenol was reduced in the resin, which resulted in the reduction of the value of phenol index, an important index when evaluating the possibility of utilisation of the used moulding sand. The last achievement was the application of the ethyl silicate as a solution of the binder components (the fourth generation). The quality, toxicity, and the emission of odour, produced when using the particular generations of polyurethane cold-box process, were confirmed by the laboratory and/or industrial tests. These tests indicated a distinct gradual improvement of the process in relation to the initial method. A considerable reduction (by about 65-75%) of the condensation of the emitted toxic substances such as: benzene, toluene and xylene was stated. The emission of the odour and fumes was also considerably reduced, especially after the application of ethyl silicate as a solvent of the binder components. This new solvent also reduced the tendency to condensation in the products of the binder pyrolysis. The reduction of the emission factor (according to the German LAGA regulations) makes easier the management of moulding matenals in a foundry shop as regards the possibility to reuse the waste sand. These advantageous changes are of an essential practical importance because now about 50% of cores are made by the cold-box method and the application of the modified variants of the polyurethane cold-box process considerably improves the working conditions, the environmental protection, work safety and economy of foundry materials in foundries.

10

Metoda bilansowania materiałów formierskich w procesie odlewania

Dzwonnik I.

Archiwum Odlewnictwa

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2002

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R. 2, nr 5

39--47

PL

W artykule przedstawiono metodę budowy i funkcjonowania bilansu materiałów biorących udział w procesie wytwarzania odlewów. Ważna cechą przyjętej metody jest przyporządkowanie bilansów cząstkowych obejmujących wszystkie materiały biorące udział w procesie wytwarzania oraz zamykanie bilansu na każdym etapie procesu. Podstawowym bilansem jest dzienny rozchód materiałów, który stanowi składową bilansów tygodniowych i następnie miesięcznych itd. Przedstawiono również konieczne warunki do wprowadzenia bilansu w odlewni.

EN

Method of balancing moulding materials in a casting process has been presented in the paper. The assignment of all used materials in the balance and closing of the balance in every stage of the process are the important features of the elaborated method. The basic element of the balance is daily expenditure of materials, which in turn is the component of weekly, and in consequence monthly consumption of materials, etc. The necessary conditions for implementation of the balance in a casting house are also presented.