Modeling of mold filling of Al gravity casting and validation with X-ray in-situ observation

In the mold filling simulation, element parameters including volume filled ratio, surface dimensionless distance, and surface filled ratio, were proposed to describe the shape and location of free surfaces in DFDM (Direct Finite Difference Method) elements. A model of the filling process was established, specially taking into account the mass, momentum and heat transfer in the vicinity of free surfaces. It was applied to an experimental AC4C (Al–7Si–0.4Mg) gravity casting. With a special X-ray apparatus, in-situ observation and record of actual mold filling process of the casting were carried out. The simulation results were validated and analyzed by comparing with the observation. The liquid flowing in the casting runner and ingate as well as the evolution of free surfaces were analyzed and discussed.