Interfacial heat transfer behavior at metal/die in finger-plated casting during high pressure die casting process

Abstract

Heat transfer at the metal-die interface has a great influence on the solidification process and casting structure. As thin-wall components are extensively produced by high pressure die casting process (HPDC), the B390 alloy finger-plate casting was cast against an H13 steel die on a cold-chamber HPDC machine. The interfacial heat transfer behavior at different positions of the die was carefully studied using an inverse approach based on the temperature measurements inside the die. Furthermore, the filling process and the solidification rate in different finger-plates were also given to explain the distribution of interfacial heat flux (q) and interfacial heat transfer coefficient (h). Measurement results at the side of sprue indicates that qmax and hmax could reach 9.2 MW∙m-2 and 64.3 kW∙m-2∙K-1, respectively. The simulation of melt flow in the die reveals that the thinnest (T1) finger plate could accelerate the melt flow from 50 m∙s-1 to 110 m∙s-1. Due to this high velocity, the interfacial heat flux at the end of T1 could firstly reach a highest value 7.92 MW∙m-2 among the ends of T n (n=2,3,4,5). In addition, the qmax and hmax values of T2, T4 and T5 finger-plates increase with the increasing thickness of the finger plate. Finally, at the rapid decreasing stage of interfacial heat transfer coefficient (h), the decreasing rate of h has an exponential relationship with the increasing rate of solid fraction (f).