Thermal Analysis of Ductile Iron: A New Way to Predict the Mechanical Properties

Abstract

Thermal analysis is characterized by the recording and evaluation of the temperature curve over time. Due to the correlation between transformation temperatures and chemical composition, thermal analysis is used to determine the carbon and silicon content. Furthermore, the aim is to be able to predict mechanical properties by thermal analysis. However, all current prediction methods refer to the cooling conditions in the investigated casting area and do not allow any transfer to other cooling conditions. There is a lack of a direct and automatic prediction of the mechanical properties from the thermal analysis before casting and transfer to other cooling conditions. For this study, cooling curves from the last 10 years at the Foundry Institute at RWTH Aachen University were evaluated and correlated with the mechanical properties from castings with three different thermal modules. The results of this empirical regression analysis are equations for the investigated mechanical parameters, which can be automatically filled with the characteristic times and temperatures of a thermal analysis in the casting process and the thermal modulus from the casting. For this modulus, the user can insert a corresponding value of the structural casting part that is relevant to the quality requirements in the foundry.