Effect of different processing parameters on interfacial heat-transfer behavior in high-pressure die-casting process
(1. School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China;
2. Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Tsinghua University, Beijing 100084, China)
2. Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Tsinghua University, Beijing 100084, China)
Abstract: Vacuum die casting can reduce the “air entrapment” phenomenon during casting process. Based on the temperature measurements at metal-die interface with different processing parameters, such as slow shot speed (VL), high shot speed (VH), pouring temperature (Tp) and initial die temperature (Tm), inverse method was developed to determine the interfacial heat transfer coefficient (IHTC). The results indicate that a closer contact between the casting and die could be achieved when the vacuum system is used. It is found that the vacuum could strongly increase the values of IHTC and decrease the grain size in castings. The IHTC could have a higher peak value with increasing the Tp from 680 to 720 °C or the VL from 0.1 to 0.4 m/s. In addition, the influence of the VH and Tm on IHTC could be negligible.
Key words: vacuum die casting; interfacial heat transfer behavior; metal-die interface; externally solidified crystals