Modelling of micro and macro porosity formation in cast Etial 177 alloy

In this study, using a commercial casting simulation software and sand cast Etial 177 casting alloy micro and macro porosity which occurs due to the volumetric shrinkage during solidification, have been investigated.After being melted the Etial 177 alloy was sand cast into moulds which has a special geometrical design to produce micro and macro shrinkage. Following solidification and cooling of reel castings the measured micro and macro porosity values were compared with the porosity values obtained from computer simulation model. The cooling curve of the alloy in the computer model was defined using the time-temperature data measured from the sand castings so that a good match between the reel castings and the computer modeling was achieved. During modeling of porosity formation for precise definition of the permeability limits of the mushy zone none grain refined and well grain refined castings were used.During this study, melting, grain refining, sand casting, casting simulation, metallography, optical microscopy, microstructure presentation and image analysis techniques have been employed.Results showed good similarity between porosity obtained from simulation model of sand cast Etial 177 alloy and the porosity measured from reel castings. Results also showed one of the most important boundary condition in modeling casting the mushy zone permeability, which is defined by so called ?critical solid fraction? ratio was as low as 35% in non grain refined alloy but it increased to 50-55 % in well grain refined alloy.Key Words: Etial177, porosity, feeding ability, solidification, casting.