In the foundry industry, silica sands are the most commonly used type of sands for the production of sand foundry moulds using various types of binders. Their greatest disadvantage is their significant volume changes at elevated temperatures, which are associated with the formation of many foundry defects from stress, such as veining, and thus have a direct influence on the final quality of the casting. In the case of non-silica sands and synthetic sands, the volume stability is more pronounced, but this is accompanied by a higher purchase price. Therefore, a combination of silica sand and synthetic sand CERABEADS is considered in order to influence and reduce the thermal expansion. The hybrid mixtures of sands, and their most suitable ratios, were evaluated in detail using sieve analysis, log W and cumulative curve of granularity. It was found that the addition of 50% CERABEADS achieves a 32.2% reduction in dilatation but may increase the risk of higher stresses. The measurements showed a significant effect of the granulometric composition of the sand on the resulting thermal expansion, where the choice of grain size and sorting can achieve a significant reduction in dilatation with a small addition of CERABEADS.

Brembo Czech s r o Na Rovince 875 720 00 Ostrava Czech Republic

Department of Mechanical and Electrical Engineering ŠKODA AUTO University 293 01 Mladá Boleslav Czech Republic

Department of Metallurgical Technologies Faculty of Materials Science and Technology VSB Technical University of Ostrava 17 Listopadu 2172 15 708 00 Ostrava Czech Republic

Department of Production Logistics and Quality ŠKODA AUTO University 293 01 Mladá Boleslav Czech Republic

Zobrazit více v PubMed

Campbell J., Svidró J.T., Svidró J. ASM Handbook, Cast Iron Science and Technology. Volume 1A. ASM International; Novelty, OH, USA: 2017. Molding and Casting Processes; pp. 189–206.

Svidró J., Svidró J.T., Diószegi A. Journal of Physics Conference Series. Volume 1527. IOP Publishing; Bristol, UK: 2020. The role of purity level in foundry silica sand on its thermal properties; p. 012039.

Kowalski J.S. Thermal aspects of temperature transformations in silica sand. Arch. Foundry Eng. 2010;10:111–114.

Anwar N., Sappinen T., Jalava K., Orkas J. Comparative experimental study of sand and binder for flowability and casting mold quality. Adv. Powder Technol. 2021;32:1902–1910. doi: 10.1016/j.apt.2021.03.040. DOI

Chao C.-H., Lu H.-Y. Stress-induced β→α-cristobalite phase transformation in (Na2O + Al2O3)-codoped silica. Mater. Sci. Eng. A. 2002;328:267–276. doi: 10.1016/S0921-5093(01)01703-8. DOI

Molding Methods and Materials. Des Plaines, American Foundrymen’s Society; Schaumburg, IL, USA: 1962.

Weddington V.L., Mobley C.E. Influence of sand surface chemistry on bonding. AFS Trans. 1991;99:825–870.

Gyarmati G., Budavári I., Fegyverneki G., Varga L. The effect of sand quality on the bending strength and thermal distortion of chemically bonded sand cores. Heliyon. 2021;7:e07624. doi: 10.1016/j.heliyon.2021.e07624. PubMed DOI PMC

Svidró J., Diószegi A., Tóth L., Svidró J.T. The influence of thermal expansion of unbonded foundry sands on the deformation of resin bonded cores. Arch. Metall. Mater. 2017;62:795. doi: 10.1515/amm-2017-0118. DOI

Ravi S., Thiel J., Bryant N., Giese S., Schneiter T.J. Use of Dilatometry to Evalute the High Temperature Characteristics of Silica in Chromite Sand; Proceedings of the 73rd World Foundry Congress (WFC 2018); Kraków, Poland. 23–27 September 2018; p. 447.

Thiel J., Ziegler M., Dziekonski P., Joyce S. Investigation into the Technical Limitations of Silica Sand Due to Thermal Expansion. Trans. Am. Foundry Soc. 2007;115:383–400.

Břuska M., Beňo J., Cagala M., Jasinková V. Dilatometric characterization of foundry sands. Arch. Foundry Eng. 2012;12:9–14. doi: 10.2478/v10266-012-0027-8. DOI

Bakhtiyarov S.I., Overfelt R.A., Wang D. Thermophysical property measurements on mold materials: Thermal expansion and density. Int. J. Thermophys. 2005;26:141–149. doi: 10.1007/s10765-005-2359-x. DOI

Svidró J.T., Diószegi A., Svidró J., Ferenczi T. Thermophysical aspects of reclaimed moulding sand addition to the epoxy-SO2 coremaking system studied by Fourier thermal analysis. J. Therm. Anal. Calorim. 2017;130:1779–1789. doi: 10.1007/s10973-017-6612-x. DOI

Thiel J., Ravi S. Causes and solutions to veining defects in iron and steel castings. AFS Trans. 2014;14:1–16.

Czerwinski F., Mir M., Kasprzak W. Application of cores and binders in metalcasting. Int. J. Cast Met. Res. 2015;28:129–139. doi: 10.1179/1743133614Y.0000000140. DOI

Svidró J., Diószegi A., Svidró J.T. The origin of thermal expansion differences in various size fractions of silica sand. Int. J. Cast Met. Res. 2020;33:242–249. doi: 10.1080/13640461.2020.1838078. DOI

Thiel J. AFS Proceedings. AFS Transactions-American Foundry Society; Schaumburg, IL, USA: 2011. Thermal expansion of chemically bonded silica sand; pp. 1–10.

Hrubovčáková M., Vasková I., Benková M., Conev M. Opening material as the possibility of elimination veining in foundries. Arch. Foundry Eng. 2016;16:157–161. doi: 10.1515/afe-2016-0070. DOI

Beňo J., Adamusová K., Merta V., Bajer T. Influence of silica sand on surface casting quality. Arch. Foundry Eng. 2019;19:5–8.

Ramrattan S., Wells L., Patel P., Shoemaker J. Qualification of chemically bonded sand systems using a casting trial for quantifying interfacial defects. Int. J. Met. 2018;12:214–223. doi: 10.1007/s40962-017-0166-3. DOI

Jelínek P. Foundry Sand—Sand Mixtures Binder System. Volume 1. FTIS; Ostrava, Czech Republic: 2000. pp. 49–51.

Thiel J., Ravi S., Bryant N. Advancements in materials for three-dimensional printing of molds and cores. Int. J. Met. 2017;11:3–13. doi: 10.1007/s40962-016-0082-y. DOI

Lauermannová A.M., Lojka M., Jankovský O., Faltysová I., Pavlíková M., Pivák A., Záleská M., Pavlík Z. High-performance magnesium oxychloride composites with silica sand and diatomite. J. Mater. Res. Technol. 2021;11:957–969. doi: 10.1016/j.jmrt.2021.01.028. DOI

Dilatation of New Progressive Hybrid Sand and Its Effect on Surface Structure, Roughness, and Veining Creation within Grey Cast Iron