Prediction of hot tearing susceptibility of direct chill casting of AA6111 alloys via finite element simulations
(1. School of Materials, Beijing Institute of Technology, Beijing 100081, China;
2. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China;
3. Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China)
2. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China;
3. Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China)
Abstract: To predict hot tearing susceptibility (HTS) during solidification and improve the quality of Al alloy castings, constitutive equations for AA6111 alloys were developed using a direct finite element (FE) method. A hot tearing model was established for direct chill (DC) casting of industrial AA6111 alloys via coupling FE model and hot tearing criterion. By applying this model to real manufacture processes, the effects of casting speed, bottom cooling, secondary cooling, and geometric variations on the HTS were revealed. The results show that the HTS of the billet increases as the speed and billet radius increase, while it reduces as the interfacial heat transfer coefficient at the bottom or secondary water-cooling rate increases. This model shows the capabilities of incorporating maximum pore fraction in simulating hot tearing initiation, which will have a significant impact on optimizing casting conditions and chemistry for minimizing HTS and thus controlling the casting quality.
Key words: vehicle light-weighting; AA6111 alloy; direct chill casting; hot tearing criterion; pore fraction; finite element simulation