The Effect of Successive Stages of the Melting Process on the Nucleation of Ductile Cast Iron

Abstract

The article discusses issues related to the melting of grey and ductile cast iron in terms of metallurgical quality. The derivative and thermal analysis (DTA) was used to assess this quality. The article presents the results of research carried out in industrial conditions and analysed by the Itaca system. In the paper, the effect of the furnace type, the charge materials and the inoculation process on the parameters characterising the cast iron being melted was analysed. The most important of these are the minimum eutectic temperature (Te min), the liquidus temperature (T liquidus) and the nucleation rate. The results of the research and calculations are shown in graphs and as dependencies. Some of DTA results were compared to the microstructure analysis results. The article shows that the derivative and thermal analysis is a very effective tool in the assessment of the metallurgical quality of cast iron. It is a very good addition to chemical analysis. Based on the results of the research, it was concluded that a very high correlation exists between the rate of nucleation (DTA) and the number of graphite nuclei (microstructure analysis). Furthermore, it was also found that an improvement in nucleation could be achieved by ensuring a high value of carbon equivalent (CE) and, above all, by conducting the primary and secondary inoculation processes, respectively.

Keywords

• grey and ductile cast iron
• inoculation
• dta
• minimum eutectic temperature (temin)
• nucleation