Estimating the mechanical properties of iron castings using an approach based on solidification time. This is the goal of the study conducted by Fonderie di Montorso in collaboration with the University of Padua.
Professor Paolo Ferro from the Department of Management and Engineering of Industrial Systems and Stefano Padovan, R&D manager of Fonderie di Montorso, presented this research at the last Assofond Congress. The research has attracted interest from the scientific community and those working in the industry, as demonstrated by its recent publication in the magazines “International Journal of Metalcasting” and “Acta Metallurgica Slovaca”.
A new methodology for predicting the mechanical properties of castings
Today, customers increasingly need to know the mechanical properties at various points of a casting. The conventional testing method involved sampling portions of the casting and subjecting them to tensile testing, which was very costly and increased production times. Moreover, this procedure does not produce repeatable data, and sampling and testing can often be difficult or infeasible, especially for castings with complex geometries and low thicknesses.
The aim of this study was therefore to develop and validate a scientifically tested method that is simpler, faster and less costly, using numerical simulation to identify the mechanical properties of iron castings without sacrificing them.
The study found that the determining factor for the mechanical properties of castings is not their thickness, but their solidification time. Special software, calibrated with real verifications, produces a master curve for each type of cast iron, which correlates the solidification time with the breaking load at each point on the casting.
Tensile strength and fatigue strength
All specifications refer to tensile strength. It is a static test to assess resistance to a single strong stress, up to breaking point. Alongside this, for some types of casting, there is an increasing demand to establish another property of a dynamic nature: fatigue strength. In this case, the casting is subjected to several cycles of repeated stress. One possible development of the “solidification time-mechanical properties” model, if suitably studied and developed, could also produce interesting results related to the fatigue strength properties of castings.