Evaluation of Thermal Analysis Parameters in Relation to Shrinkage Formation in Castings Made of Ferrous Alloys

Ing. Patrik Fedorko¹; Ing. Zuzana Miškovičová, PhD.¹; doc. Ing. Branislav Buľko, PhD.¹; doc. Ing. Bc. Martina Hrubovčáková, PhD.¹; doc. Ing. Peter Demeter, PhD.¹; Ing. Slavomír Hubatka, PhD.¹; Ing. Lukáš Fogaraš, PhD.¹; Ing. Jaroslav Demeter, PhD.¹

¹TECHNICAL UNIVERSITY OF KOŠICE, Faculty of Materials, Metallurgy and Recycling, The Institute of Metallurgical Technologies and Digital Transformation, Letná 1/9, 042 00 Košice, SR, patrik.fedorko@tuke.sk

The paper deals with the evaluation of thermal analysis parameters in relation to the formation of shrinkage cavities during the casting of cast iron castings with EN-GJS-500-7 spheroidal graphite. The evaluation was performed on eight melts using single-cup thermal analysis with OCC equipment. The graphitic eutectic temperature, cementite eutectic temperature, and eutectic graphitization ability (EGS) were calculated from the chemical composition. At the same time, the parameter θ, expressing the change in the dynamics of the eutectic reaction, was determined from the first derivative of the cooling curve.

The results showed that no clear correlation was confirmed between the EGS value and the occurrence of shrinkage. On the contrary, the parameter θ showed higher sensitivity, with higher angle values recorded for melts with shrinkage. The findings point to the importance of dynamic analysis of the solidification process in assessing the risk of volume defects and may contribute to the validation of numerical solidification models within digital twin concepts applied in controlled mould systems.

Key words: Thermal analysis; Ductile cast iron; Shrinkage porosity; Cooling curve; Eutectic reaction; θ parameter

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