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Determination of application possibilities of microwave heating in the curing process of water glass molding sands with fluid esters. Part 1

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

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2009

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tom Vol. 9, iss. 1

45-50

EN

This article presents results of the experimental trial of combination of the chemical method of water glass molding sands' curing, used in foundry industry, with an innovative microwave heating. The research objective was to indicate at new areas of microwave energy application. The sands prepared, according to recommendations for curing technology, with the use of ethylene glycol diacetate, have been subject to microwave influence. The attempt at determination of microwave influence on qualitative changes of the binding bridges created during the curing process concerned such parameters as: bending and tensile strength, permeability as well as wear resistance. Moreover, we also determined the influence of microwave curing on the phenomena accompanying the process as well as bond stability (storage time of the prepared molding and core sands). It has been found, basing on the result analysis, that the innovative microwave heating might constitute a very good supplementation of the ester curing method. The advantages of the combined chemical and microwave gelation process include, among others, improvement of the described resistance and technological parameters as well as significant decrease of preparation time of foundry moulds and cores. The subject discussed in this article will be continued in its second part.

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Determination of application possibilities of microwave heating in the curing process of water glass molding sands with fluid esters. Part 2

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

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2009

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tom Vol. 9, iss. 1

51-56

EN

This article, constituting continuation of the subject discussed in the first part, presents results of the experimental trial of water glass molding sands' curing method modification with application of fluid esters and innovative microwave heating. The research objective was to determine possibilities of microwave application for curing of water glass molding sands prepared with addition of hardening agents sold under the trade name of Mach. After initial chemical curing molding sands, prepared with addition of the above mentioned hardeners, have been heated with microwaves in order to determine their influence on changes of basic technological and strength parameters of the sands, and indirectly on the quality of quartz grains binding. Studies aimed at determination of water content changes in the sands have also been undertaken. As our studies demonstrated, microwave heating allows for quick reduction of water content, thus resulting in improvement of strength parameters such as bending and tensile strength. Application of the combined methods of ester curing and innovative microwave heating facilitates production of high quality foundry moulds and cores, while simultaneously improving mould and core preparation procedures at the foundries and as a result reduces their time to an indispensable minimum.

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Microwaves energy in curing process of water glass molding sands

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

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2007

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tom Vol. 7, iss. 1

183-188

EN

This work presents the results of investigation of microwave heating on hardening process of water glass molding sands. Essential influence of this heating process on basic properties such as: compression, bending and tensile strength as well as permeability and abrasion resistance has been found. It has been proved, that all investigated sorts of sodium water glass with a module between 2.0 and 3.3 can be used as a binder of molding sands in microwave curing process. It has been found during analysis of research results of sands with 2.5 % water glass addition that they are practically the same as in case of identical molding sands dried for 120 minutes at the temperature of 110°C, used for comparative purposes. Application of microwave curing of molding sands with water glass, however, guarantees reduction of hardening time (from 120 to 4 minutes) as well as significant reduction of energy consumption. Attempts of two stage hardening of the investigated water glass molding sands have also been carried out, that is after an initial hardening during a classical CO_2 process (identical sands have also been tested for comparison after CO_2 blowing process) and additional microwave heating. It has been found that application of this kind of treatment for curing sands with 2.5 % sodium water glass content and module from 2.0 up to 3.3 results in the improvement of properties in comparison to classical CO_2 process.

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The influence of microwave curing time and water glass kind on the properties of molding sands

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

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2007

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tom Vol. 7, iss. 4

79-82

EN

This work presents results of research on the influence of microwave heating time on the process of hardening of water glass molding sands. Essential influence of this drying process on basic properties such as: compression, bending and tensile strength as well as permeability and wear resistance, has been found. It has been proved, that all the investigated sorts of sodium water glass could be used as binding material of molding sands intended for curing with the microwave process heating. It has been found, while analyzing the results of property studies of microwave heated molding sands with 2.5% addition of water glass, that all available on the market kinds of this binding agent (including the most frequently used in foundry 145 and 149 kinds) after microwave heating guarantee very good compression, bending and tensile strength as well as permeability and wear resistance. Moreover, it has been determined that the optimal curing time of molding sands containing various kinds of water glass is 240 seconds. After this time, all basic properties of molding sands are stable. The use of microwave curing of water glass molding sands results in a significant decrease of hardening process time, full stabilization of molding sands as well as much lower energy consumption.