Aplicação da análise térmica no processo de fabricação de ferro fundido cinzento

Abstract

Casting is one of the oldest metallurgical process, multipurpose, and of great scalability in production. It is widely used in manufacturing semi-finished parts with complex geometry, presenting a highly competitive cost with other production methods. Cast Iron is the most commonly used material in large-scale casting. This research presents a study of the solidification of commercial gray cast iron alloys using Thermal Analysis as a metallurgical control tool, emphasizing the degree of recalescence and its relationship with the microstructure obtained before inoculation. In the development of this work, the techniques of thermal analysis, optical spectrometry, metallographic analysis, and Brinell hardness test were employed. Hypo-eutectic and hyper-eutectic alloy samples were taken when the metal was melting and submitted to thermal analysis and spectrometry. Also, samples were taken for optical microscopy analysis. Brinell hardness measurements were also performed on these samples. From the experimental data began the phase of treatment of the information obtained; the cooling curves had their data compiled and treated by Labplot software to generate the curves as well as images of metallography, which were analyzed to obtain data such as the number of eutectic cells by ImageJ software. the main results are highlighted: Rosario's (2012) equations can be used to predict the stable eutectic temperature (TEE) and metastable eutectic temperature (TEM) from the chemical analysis, these showed a difference of 0.09% to 0.41% between the calculated TEE and supercooling temperatures (TSE) measured in the experimental part; recalescence can be related to the number of eutectic cells hypo eutectic cast irons, as it is an easy value to determine recalescence can be used in predicting the numbers of eutectic cells and mechanical properties of batches of cast irons of the same grade Inoculation can be evaluated by the reduction of recalescence in relation to lots without inoculation.