Effects of cooling rate on microstructure in EN-AC43000 gravity castings and related T6 mechanical properties.

The aim of this work is to asses a correlation law between local cooling rate and SDAS for the EN AC43000 cast alloy. Bars 200 mm long with a double T cross section (suitable for tensile testing) were sand cast under controlled processing conditions. Chillers of different dimensions and materials, including water cooled ones, were placed at one side of the casting in order to obtain mono-dimensional heat flux and different cooling rates throughout the casting length. Thermocouples were used to acquire local cooling curves. A campaign of FE simulations was run to fine tune boundary conditions and to obtain a reliable cooling rate distribution throughout the whole casting. A correlation between experimental SDAS and simulated cooling rates was assessed. Finally, mechanical properties from extracted specimens in T6 condition were related to local SDAS and Cooling Rate.