The mold filling and solidification simulation for the high pressure die casting (HPDC) and low pressure die casting (LPDC) processes were studied. A mathematical model considering the turbulent flow and heat transfer...The mold filling and solidification simulation for the high pressure die casting (HPDC) and low pressure die casting (LPDC) processes were studied. A mathematical model considering the turbulent flow and heat transfer phenomenon during the HPDC process has been established and parallel computation technique was used for the mold filling simulation of the process. The laminar flow characteristics of the LPDC process were studied and a simplified model for the mold filling process of wheel castings has been developed. For the solidification simulation under pressure conditions, the cyclic characteristics and the complicated boundary conditions were considered and techniques to improve the computational efficiency are discussed. A new criterion for predicting shrinkage porosity of Al alloy under low pressure condition has been developed in the solidification simulation process.展开更多
Three types of near-net shape casting alumi- num parts were investigated by computed tomography to determine casting defects and evaluate quality. The first, second, and third parts were produced by low-pressure die c...Three types of near-net shape casting alumi- num parts were investigated by computed tomography to determine casting defects and evaluate quality. The first, second, and third parts were produced by low-pressure die casting （Al-12Si-0.8Cu-0.5Fe-0.9Mg-0.7Ni-0.2Zn alloy）, die casting （A356, A1-7Si-0.3Mg）, and semi-solid casting （A356, A1-TSi-0.3Mg）, respectively. Unlike die casting （second part）, low-pressure die casting （first part） sig- nificantly reduced the formation of casting defects （i.e., porosity） due to its smooth filling and solidification under pressure. No significant casting defect was observed in the third part, and this absence of defects indicates that semi- solid casting could produce high-quality near-net shape casting aluminum parts. Moreover, casting defects were mostly distributed along the eutectic grain boundaries. This finding reveals that refinement of eutectic grains is necessary to optimize the distribution of casting defects and reduce their size. This investigation demonstrated that computed tomography is an efficient method to determine casting defects in near-net shape casting aluminum parts.展开更多
基金The work was financially supported by the Significant Fundamental Research Development & Planning of China (G2000067208-3) the Significant Project of the National Natural Science Foundation of China (59990470-3)and the internal research fund of Tsing
文摘The mold filling and solidification simulation for the high pressure die casting (HPDC) and low pressure die casting (LPDC) processes were studied. A mathematical model considering the turbulent flow and heat transfer phenomenon during the HPDC process has been established and parallel computation technique was used for the mold filling simulation of the process. The laminar flow characteristics of the LPDC process were studied and a simplified model for the mold filling process of wheel castings has been developed. For the solidification simulation under pressure conditions, the cyclic characteristics and the complicated boundary conditions were considered and techniques to improve the computational efficiency are discussed. A new criterion for predicting shrinkage porosity of Al alloy under low pressure condition has been developed in the solidification simulation process.
文摘Three types of near-net shape casting alumi- num parts were investigated by computed tomography to determine casting defects and evaluate quality. The first, second, and third parts were produced by low-pressure die casting （Al-12Si-0.8Cu-0.5Fe-0.9Mg-0.7Ni-0.2Zn alloy）, die casting （A356, A1-7Si-0.3Mg）, and semi-solid casting （A356, A1-TSi-0.3Mg）, respectively. Unlike die casting （second part）, low-pressure die casting （first part） sig- nificantly reduced the formation of casting defects （i.e., porosity） due to its smooth filling and solidification under pressure. No significant casting defect was observed in the third part, and this absence of defects indicates that semi- solid casting could produce high-quality near-net shape casting aluminum parts. Moreover, casting defects were mostly distributed along the eutectic grain boundaries. This finding reveals that refinement of eutectic grains is necessary to optimize the distribution of casting defects and reduce their size. This investigation demonstrated that computed tomography is an efficient method to determine casting defects in near-net shape casting aluminum parts.
