Modeling of Mechanical Properties in Castings

Mechanical properties of castings are not homogenous due to defects and variable solidification rates. In high strength alloys, which are specified for structural applications, that variability is of great concern since it can impact the performance of the part during use. Understanding this variability is important to optimize casting design for the customer and to guide the foundry to integrating the filling and risering with component requirements as well as achieving a casting with low levels of defects. Many solidification software packages can predict some components of mechanical property levels, such as dendrite arm spacing or grain size, but fall short of actual predictive properties in specific alloy systems. In part, this is due to differing responses of properties to solidification rate and defects, which is alloy specific. This work details an attempt to develop static property predictions in an A206 aluminum alloy under solidification conditions that are typical for relatively large structural castings. Solidification analysis was coupled with mechanical property data from samples excised from the casting to modify software code to be predictive of actual mechanical properties in this alloy system. Improved accuracy using this approach sets the stage for elimination or reduction of the “casting factor” used for cast part design, resulting in more efficient part manufacture.