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Li Y.-D.,Lanzhou University of Technology | Apelian D.,Metal Processing Institute MPI | Xing B.,Lanzhou University of Technology | Ma Y.,Lanzhou University of Technology | Hao Y.,Lanzhou University of Technology
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2010

Semisolid processing is now a commercially successful manufacturing route to produce net-shape parts in automotive industry. The conspicuous results of alloy optimization with thermodynamic simulations for semisolid processing of commercial AM60 alloy were present. The results indicate that the available processing temperature range of AM60 alloy is 170 °C. The temperature sensitivity of solid fraction decreases with increasing solid fraction or with decreasing temperature above eutectic reaction temperature of AM60 alloy. When the solid fraction φs is 0.4, corresponding processing temperature is 603.8 °C and the sensitivity -dφs/dT is 0.0184. The effects of various alloying elements on the solidification behavior and SSM processability of AM60 alloy were calculated with Pandat software. © 2010 The Nonferrous Metals Society of China.

Nusskern P.,Karlsruhe Institute of Technology | Hoffmeister J.,Metal Processing Institute MPI | Schulze V.,Karlsruhe Institute of Technology | Sisson R.,Metal Processing Institute MPI
Proceedings - European Conference on Heat Treatment and 21st IFHTSE Congress | Year: 2014

Immersion quenching in liquids leads to three different quenching stages, namely film boiling, nucleate boiling and convection. In case of heat treating powder metallurgical (PM-) components, the surface pores influence the heat dissipation. Open porosity tends to break the vapor film and leads to an earlier transition from film to nucleate boiling Since pores act as nucleation sites for the bubble formation, a growing number of bubbles can be detected for an increasing porosity. Thus, the heat transfer coefficient is increasing. In this study, experimental quenching curves for samples of different densities were measured and the heat transfer coefficient was calculated in dependency of the temperature and the porosity. Ultimately, the results are transferred into a heat transfer coefficient model. This contribution is a result of a partnership between Metal Processing Institute and Institute for Applied Materials with the objective to push the research in the field of heat treatment.

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