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A s one of the most cost effective near-net-shape manufacturing processes, high pressure die casting (HPDC) accounts for almost 70% of aluminum components production [1] . It has been demonstrated that the HPDC process involves rapid temperature fluctuations on the surface of the die during the fast casting cycles. This behavior could result in steep thermal gradients on and below the die surface [2][3][4][5][6] . According to research articles [7,8] , the solidification rate is highly dependent on the interfacial heat transfer behavior in both the shot sleeve and the die. Subsequently, solidification rate has a significant influence on the microstructural defect formation and mechanical Abstract: To predict the heat transfer behavior of A380 alloy in a shot sleeve, a numerical approach (inverse method) is used and validated by high pressure die casting (HPDC) experiment under non-shooting condition. The maximum difference between the measured and calculated temperature profiles is smaller than 3 °C, which suggests that the inverse method can be used to predict the heat transfer behavior of alloys in a shot sleeve. Furthermore, the results indicate an increase in maximum interfacial heat flux density (q max ) and heat transfer coefficient (h max ) with an increase in sleeve filling ratio, especially at the pouring zone (S2 zone). In addition, the values of initial temperature (T IDS ) and maximum shot sleeve surface temperature (T simax ) at the two end zones (S2 and S10) are higher than those at the middle zone (S5). Moreover, in comparison with fluctuations in heat transfer coefficient (h) with time at the two end zones (S2 and S10), 2.4-6.5 kW•m -2 •K -1 , 3.5-12.5 kW•m -2 •K -1 , respectively, more fluctuations are found at S5 zone, 2.1-14.7 kW•m -2 •K -1 . These differences could theoretically explain the formation of the three zones: smooth pouring zone, un-smooth middle zone and smooth zone, with different morphologies in the metal log under the non-shot casting condition. Finally, our calculations also reveal that the values of q max and h max cast at 680 °C are smaller than those cast at 660 °C and at 700 °C. Key words: inverse method; A380 casting; filling ratio; heat transfer behavior CLC numbers: TG146.21 Document code: A Article ID: 1672-6421(2016)04-269-07properties of the final product. Furthermore, the solidification condition could affect the morphology and quantity of externally solidified crystals (ESCs) or cold flakes in the casting [9,10] . Therefore, to reduce defects in castings and achieve an optimized control condition, a thorough understanding of the heat transfer between the molten metal and the shoot sleeve is necessary. Temperature measurement is the most difficult task in interfacial heat transfer determination in HPDC. Dour et al. [11] pointed out that improper installation of the thermocouples could bring uncertainties in temperature measurement. To date, there are two main problems existing in casting and die temperature measurement: (I) accurate and reproducible measurements are ...

H igh pressure die casting (HPDC) is extensively used for mass production, due to the high productive efficiency of a desired component in a rapid solidification speed [1,2] . When HPDC molten alloy is injected into a relatively cold cavity of a die, the solidification rate is highly dependent on the interfacial heat transfer behavior in both the die and the molten alloy [3] , and subsequently influences the microstructure and the consequent mechanical properties of the final product [4][5][6][7] . In other words, a proper high cooling rate could favor the formation of fine microstructure in produced castings. Otherwise, too rapid a cooling rate could cause the premature solidification of the molten metal before the filling completion.Many studies have been carried out to investigate 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 . Due to this high velocity, the interfacial heat flux at the end of T 1 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 q max and h max values of T 2 , T 4 and T 5 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).Key words: high pressure die casting (HPDC); interfacial heat transfer behavior; metal/die interface; solidification speed; solid fraction CLC numbers: TG146.1

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