Effect of Mould Temperature and Melt Treatment on Properties of an AlSi9 Cast Alloy - Thermal and Microstructural Investigations

Abstract

In this study we used the cast TATUR samples that promotes the formation of an AlSi alloy porosity through a variable temperature gradient from top to bottom of the specimen. The die (permanent mold) was instrumented by thermocouples in order to follow the cooling of the specimen in several emplacements. Thermal analyses via cooling curves have been correlated to the microstructural data (SDAS measurement). Samples were cut from all castings and analyzed by optical microscopy in order to get the Secondary Dendrite Arm Spacing (SDAS) variation in function of cooling rates in the casting. The present work shows the effect of various pre-heating mould temperature and melt treatment on secondary dendrite arm spacing.

FEM Simulation of the Effect of Mold Initial Temperature on Carbon Macrosegregation in Large-Size Steel Ingots

“…These spatial constraints could result in variable mold temperatures, thereby affecting the solidification kinetics. Up to now, it has been reported that a rise in initial mold temperature coarsens grain size [7,8], increases the secondary dendrite arm spacing (SDAS) [8,9], aggravates shrinkage porosities [8], and prolongs the solidification time [8,9,10]. However, its impact on macrosegregation in large size steel ingots is still not clear and needs to be quantified.…”