Stress-Strain Predictions of Semisolid Al-Mg-Mn Alloys During Direct Chill Casting: Effects of Microstructure and Process Variables
Abstract
The occurrence of hot tearing during the industrial direct chill (DC) casting process results in significant quality issues and a reduction in productivity. In order to investigate their occurrence, a new semisolid constitutive law (Phillion et al.) for AA5182 that takes into account cooling rate, grain size, and porosity has been incorporated within a DC casting finite element process model for round billets. A hot tearing index was calculated from the semisolid strain predictions from the model. This hot tearing index, along with semisolid stress-strain predictions from the model, was used to perform a sensitivity analysis on the relative effects of microstructural features ( e.g., grain size, coalescence temperature) as well as process parameters ( e.g., casting speed) on hot tearing. It was found that grain refinement plays an important role in the formation of hot cracks. In addition, the combination of slow casting speeds and a low temperature for mechanical coalescence was found to improve hot tearing resistance.
- Publication:
-
Metallurgical and Materials Transactions B
- Pub Date:
- October 2013
- DOI:
- 10.1007/s11663-013-9902-0
- Bibcode:
- 2013MMTB...44.1287J