Quality indices and quality charts were used as evaluation tool for selecting the optimum conditions to be applied in practice in order to develop superior tensile properties and optimum quality in Al-Si casting alloys. The right alloy quality in engineering applications involves reaching a suitable compromise between numerous factors so as to present the maximum performance combined with cost efficiency. Alloy composition, solidification rate, and heat treatment procedures, are all parameters which closely affect alloy quality since they also influence the tensile properties of the casting. The quality of aluminum alloy castings may be defined using numerical values which correlate to their mechanical properties. Several models were proposed to correlate the quality of the Al-Si castings to the mechanical properties of these alloys.