The impact of defects on the quality of aluminium alloy die castings

摘要

High-pressure die-costing is widely used in the automotive field for the possibility of obtaining net to shape components of complex geometry and thin wall thickness at high production rates. A number of process parameters exists, which, if not adequately determined and adjusted, result in a decadence of quality of the die cast part Common defects in die castings are shrinkage cavities, cold fills, oxide skins, dross, entrapped air bubbles. It's common opinion that defects can make the mechanical behaviour of castings unpredictable. The influence of casting defects on the mechanical properties of die cast aluminium alloys is described below. Castings with thin sections, like those produced by high-pressure die-casting, are vulnerable to the effect of defects since a single macro-defect can cover a significant fraction of the cross-section area. As a consequence, it is important to understand and predict the effect of defects on mechanical properties of die cast components to obtain substantial technological improvements.