Determination of the metal/die interfacial heat transfer coefficient and its application in evaluating the pressure distribution inside the casting during the high pressure die casting process

Abstract

High pressure die casting (HPDC) experiments were conducted on a 650 t cold chamber die casting machine to study the interfacial heat transfer behaviour between casting and die. A 'step shape' casting and two commercial alloys namely ADC12 and AM50 were used during the experiments. Temperature and pressure measurements were made inside the die and at the die surface. The metal/die interfacial heat transfer coefficient (IHTC) was successfully determined based on the measured temperature inside the die by solving the inverse heat transfer problem. The IHTC was then used as the boundary condition to determine the 3-D temperature field inside the casting. Based on the predicted temperature distribution, the pressure distribution inside the casting was evaluated by assuming that the transferred pressure from the plunger tip of the injection side to the casting is primarily influenced by the solid fraction of the casting. Reasonable agreement was found between the determined pressure values and the measured pressures at the die surface of the casting.