New Possibilities with Improved Green Sand Testing Equipment

Abstract:

The quality of green sand moulds is paramount for the casting quality and reduction of surface defects. The general knowledge within foundries on green sand properties and its influence on casting defect behaviour has significantly decreased as a result of outsourced external sand testing and dependence on external consultants. Moreover, academic R&D activities targeting studies on green sand properties could not attract significant funding and have hence been limited to small extents. It cannot be stressed enough that in sand casting the majority of casting defects can be related to an insufficient green sand management. Recent research and development has been only supported by suppliers of the foundry industry, however, with a major emphasis on anorganic water glass binder systems and the reduction of phenolic binders in organic binders to reduce emission and unpleasant smells while simultaneously increasing e.g. fluidity or strength. In most industrial environments hand-operated sand testing machines, whose basic concepts of operation were developed in the middle of the last century, are still used. While these old fashioned apparatuses can help to maintain quality in a foundry they are not suited to provide additional information on the green sand quality. Therefore, any developments on different mould materials were mainly performed with very old fashioned manually operated sand testing equipment and a significant aspect of the development of more accurate modern sand testing equipment was neglected. Nevertheless, these manually operated sand testing apparatuses represent the current state-of-the-art of sand testing equipment. In order to improve green sand properties and gain additional knowledge it is essential to develop new testing methods. This paper will give information on the development of novel green sand testing equipment for compaction, pressure, as well as wet strength testing development at the ÖGI and gives comparison to values obtained by manually operated machines. The main advantage of modern electronical testing machines is a higher accuracy of measurement in general and the possibility of recording stress-strain-curves. This work shows characteristic stress-strain-curves for all mechanical green sand testing methods as well as the influence of water content on the progression of mechanical properties. As a result the area with the best handling properties of green sand is shown. Furthermore negative influences of defective sand specimens and marginal deviations in the testing process on the testing result have been investigated.

• Periodical: Materials Science Forum (Volume 925)
• Pages: 504-511
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.925.504
• Online since: June 2018
• Authors: Hubert Kerber*, Philipp Jakesch, Gerhard Schindelbacher, Peter Schumacher
• Keywords: Green Sand Testing, Improved Electronic Measurements, Stress-Deformation-Curves

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