Determination of interfacial Heat Transfer Coefficients in a sand mould casting process using an optimized inverse analysis

Gianfranco Palumbo, Vito Piglionico, Antonio Piccininni, Pasquale Guglielmi, Donato Sorgente, Luigi Tricarico (Politecnico di Bari)

CHALLENGE - Determination of the interface heat transfer coefficients in casting processes represents a fundamental step in the creation of a reliable numerical model that can predict some of the most common defects (for example hot tear or residual stress). This work focuses on the best methodology to find the heat transfer coefficients for the numerical modeling of the casting process of superduplex stainless steel (ASTM A890 Gr. 5A) using a silica sand mould.  

SOLUTION - The purpose of the optimization procedure was to minimize the error between the numerical and the experimental temperature evolution. Experimental instrumented castings were used to acquire (both in the casting and in the sand) temperature changes for a number of points of interest by means of thermocouples. The entire process was simulated using software package MAGMASOFT in order to calculate the temperature at the same points at any step of the process. Optimization was done using a multi-objective genetic algorithm MOGA-II in modeFRONTIER, with the goal of finding optimal values for the input parameters.  

BENEFITS - As confirmed by the numerical simulations using the results of the optimization procedure in modeFRONTIER, the methodology helped determine the correct values of the input variables for modeling the casting process of the ASTM A890 Gr.5A. Final values of the optimization procedure are shown on the table to the right.