Papers by Author: Carlos A. Silva Ribeiro

Abstract: This paper describes one possible method to anticipate and control the development of solidification shrinkage, during solidification of nodular cast iron melts, based upon industrial trials made using special designed test castings and closed volume thermal analysis cartridges.The methodology considers both the solidification morphology and solidification shrinkage critical size, which is always a difficult component of analysis, along with a developed contraction defect index, that allows the application to several types of molten metal and inoculation practices.The use of thermal analysis allows the recognition of unique melt characteristics, in real time, that are not accessed by more traditional measurement equipment. This allows the definition of thermal analysis patterns that characterize the best melt quality for self-feeding. This is a practical to use and powerful tool for modern foundries, taking advantage of new metric, data collection and data analysis. We aim to contribute to scientific knowledge and simultaneously to provide information that can be useful for foundries to improve their process efficiency.

Abstract: Macro and microporosity in castings are a problem that persists at many foundries, despite the use of advance simulation software’s. This fact indicates that other parameters rather then the casting shape/design or the “standard” metallurgical characteristics are not properly controlled, considered or modelled in the solidification simulation. In this paper we present the Phase I of a research project, which consists on a bibliographic review of the previous attempts to evaluate the relationship between solidification sequence and the measurement of expansion of molten metal during eutectic solidification and is relation to porosity and shrinkage defects.