In this paper,the research progress of the interfacial heat transfer in high pressure die casting(HPDC)is reviewed.Results including determination of the interfacial heat transfer coefficient(IHTC),influence of castin...In this paper,the research progress of the interfacial heat transfer in high pressure die casting(HPDC)is reviewed.Results including determination of the interfacial heat transfer coefficient(IHTC),influence of casting thickness,process parameters and casting alloys on the IHTC are summarized and discussed.A thermal boundary condition model was developed based on the two correlations:(a)IHTC and casting solid fraction and(b)IHTC peak value and initial die surface temperature.The boundary model was then applied during the determination of the temperature field in HPDC and excellent agreement was found.展开更多
The high pressure die casting (HPDC) process is one of the fastest growing and most efficient methods for the production of complex shape castings of magnesium and aluminum alloys in today's manufacturing industry...The high pressure die casting (HPDC) process is one of the fastest growing and most efficient methods for the production of complex shape castings of magnesium and aluminum alloys in today's manufacturing industry. In this study, a high pressure die casting experiment using AZ91D magnesium alloy was conducted, and the temperature profiles inside the die were measured. By using a computer program based on solving the inverse heat problem, the metal/die interfacial heat transfer coefficient (IHTC) was calculated and studied. The results show that the IHTC between the metal and die increases right after the liquid metal is brought into the cavity by the plunger, and decreases as the solidification process of the liquid metal proceeds until the liquid metal is completely solidified, when the IHTC tends to be stable. The interfacial heat transfer coefficient shows different characteristics under different casting wall thicknesses and varies with the change of solidification behavior.展开更多
A method based on die casting experiments and mathematic modeling is presented for the determination of the heat flow density (HFD) and interfacial heat transfer coefficient (IHTC) during the high pressure die cas...A method based on die casting experiments and mathematic modeling is presented for the determination of the heat flow density (HFD) and interfacial heat transfer coefficient (IHTC) during the high pressure die casting (HPDC) process.Experiments were carried out using step shape casting and a commercial magnesium alloy,AM50.Temperature profiles were measured and recorded using thermocouples embedded inside the die. Based on these temperature readings,the HFD and IHTC were successfully determined and the calculation results show that the HFD and IHTC at the metal-die interface increases sharply right after the fast phase injection process until approaching their maximum values,after which their values decrease to a much lower level until the dies are opened.Different patterns of heat transfer behavior were found between the die and the casting at different thicknesses.The thinner the casting was,the more quickly the HFD and IHTC reached their steady states.Also,the values for both the HFD and IHTC values were different between die and casting at different thicknesses.展开更多
The interfacial heat transfer behavior at the metalJshot sleeve interface in the high pressure die casting (HPDC) process of AZ91D alloy is carefully investigated. Based on the temperature measurements along the sho...The interfacial heat transfer behavior at the metalJshot sleeve interface in the high pressure die casting (HPDC) process of AZ91D alloy is carefully investigated. Based on the temperature measurements along the shot sleeve, inverse method has been developed to determine the interfacial heat transfer coefficient in the shot sleeve. Under static condition, Interracial heat transfer coefficient (IHTC) peak values are 11.9, 7,3, 8.33kWm-2K-1 at pouring zone (S2), middle zone (S5), and end zone (510), respectively. During the casting process, the IHTC curve displays a second peak of 6.1 kWm-2 K-1 at middle zone during the casting process at a slow speed of 0.3 ms 1 Subsequently, when the high speed started, the IHTC curve reached a second peal〈 of 12.9 kW m-2K-1 at end zone. Furthermore, under different slow casting speeds, both the calculated initial temperature (TIDs) and the maximum temperature (Tsimax) of shot sleeve surface first decrease from 0.1 ms-1 to 0.3 ms-1, but increase again from 0.3 ms-1 to 0.6 ms-1. This result agrees with the experimental results obtained in a series of "plate-shape" casting experiments under different slow speeds, which reveals that the amount of ESCs decreases to the minimum values at 0.3 m s-1 and increase again with the increasing casting slow speed.展开更多
The current paper focuses on the influence of the process parameters on the peak values of the inter-facial heat transfer coefficient (IHTC) at metal/die interface during high pressure die casting (HPDC) process. A &q...The current paper focuses on the influence of the process parameters on the peak values of the inter-facial heat transfer coefficient (IHTC) at metal/die interface during high pressure die casting (HPDC) process. A "step shape" casting and AM50 alloy were used during the experiment. The IHTC was de-termined by solving the inverse thermal problem based on the measured temperature inside the die. Results show that the initial die surface temperature (IDST, TDI) has a dominant influence while the casting pressure and fast shot velocity have a secondary influence on the IHTC peak values. By curve fitting, it was found that the IHTC peak value (hmax) changes as a function of the IDST in a manner of hmax =eαTγDI. Such relationship between the IHTC peak value and the IDST can also be found when the casting alloy is ADC12, indicating that this phenomenon is a common characteristic in the HPDC process.展开更多
基金supported by the National Major Science and Technology Program of China(2012ZX04012011)the National Nature Science Foundation of China(51275269)
文摘In this paper,the research progress of the interfacial heat transfer in high pressure die casting(HPDC)is reviewed.Results including determination of the interfacial heat transfer coefficient(IHTC),influence of casting thickness,process parameters and casting alloys on the IHTC are summarized and discussed.A thermal boundary condition model was developed based on the two correlations:(a)IHTC and casting solid fraction and(b)IHTC peak value and initial die surface temperature.The boundary model was then applied during the determination of the temperature field in HPDC and excellent agreement was found.
文摘The high pressure die casting (HPDC) process is one of the fastest growing and most efficient methods for the production of complex shape castings of magnesium and aluminum alloys in today's manufacturing industry. In this study, a high pressure die casting experiment using AZ91D magnesium alloy was conducted, and the temperature profiles inside the die were measured. By using a computer program based on solving the inverse heat problem, the metal/die interfacial heat transfer coefficient (IHTC) was calculated and studied. The results show that the IHTC between the metal and die increases right after the liquid metal is brought into the cavity by the plunger, and decreases as the solidification process of the liquid metal proceeds until the liquid metal is completely solidified, when the IHTC tends to be stable. The interfacial heat transfer coefficient shows different characteristics under different casting wall thicknesses and varies with the change of solidification behavior.
基金This work was financially supported by the National Natural Science Foundation of China (No. 50675114) the National Basic Research Program of China (2006CB605208-2) The experiments were conducted at the Tsinghua-TOYO R&D Center of Magnesium and Aluminum Alloys Processing Technology with the help of engineers from the TOYO Machiuery & Metal Co., Ltd.
文摘A method based on die casting experiments and mathematic modeling is presented for the determination of the heat flow density (HFD) and interfacial heat transfer coefficient (IHTC) during the high pressure die casting (HPDC) process.Experiments were carried out using step shape casting and a commercial magnesium alloy,AM50.Temperature profiles were measured and recorded using thermocouples embedded inside the die. Based on these temperature readings,the HFD and IHTC were successfully determined and the calculation results show that the HFD and IHTC at the metal-die interface increases sharply right after the fast phase injection process until approaching their maximum values,after which their values decrease to a much lower level until the dies are opened.Different patterns of heat transfer behavior were found between the die and the casting at different thicknesses.The thinner the casting was,the more quickly the HFD and IHTC reached their steady states.Also,the values for both the HFD and IHTC values were different between die and casting at different thicknesses.
基金financially supported by the National Major Science and Technology Program of China(No.2012ZX04012011)the National Natural Science Foundation of China(No.51275269)
文摘The interfacial heat transfer behavior at the metalJshot sleeve interface in the high pressure die casting (HPDC) process of AZ91D alloy is carefully investigated. Based on the temperature measurements along the shot sleeve, inverse method has been developed to determine the interfacial heat transfer coefficient in the shot sleeve. Under static condition, Interracial heat transfer coefficient (IHTC) peak values are 11.9, 7,3, 8.33kWm-2K-1 at pouring zone (S2), middle zone (S5), and end zone (510), respectively. During the casting process, the IHTC curve displays a second peak of 6.1 kWm-2 K-1 at middle zone during the casting process at a slow speed of 0.3 ms 1 Subsequently, when the high speed started, the IHTC curve reached a second peal〈 of 12.9 kW m-2K-1 at end zone. Furthermore, under different slow casting speeds, both the calculated initial temperature (TIDs) and the maximum temperature (Tsimax) of shot sleeve surface first decrease from 0.1 ms-1 to 0.3 ms-1, but increase again from 0.3 ms-1 to 0.6 ms-1. This result agrees with the experimental results obtained in a series of "plate-shape" casting experiments under different slow speeds, which reveals that the amount of ESCs decreases to the minimum values at 0.3 m s-1 and increase again with the increasing casting slow speed.
基金Supported by the National Natural Science Foundation of China (Grant No. 50675114)National Basic Research Program of China ("973") (Grant Nos. 2006CB605208-2, 2005CB724105)
文摘The current paper focuses on the influence of the process parameters on the peak values of the inter-facial heat transfer coefficient (IHTC) at metal/die interface during high pressure die casting (HPDC) process. A "step shape" casting and AM50 alloy were used during the experiment. The IHTC was de-termined by solving the inverse thermal problem based on the measured temperature inside the die. Results show that the initial die surface temperature (IDST, TDI) has a dominant influence while the casting pressure and fast shot velocity have a secondary influence on the IHTC peak values. By curve fitting, it was found that the IHTC peak value (hmax) changes as a function of the IDST in a manner of hmax =eαTγDI. Such relationship between the IHTC peak value and the IDST can also be found when the casting alloy is ADC12, indicating that this phenomenon is a common characteristic in the HPDC process.