Abstract
Porthole extrusion is a useful process for manufacturing lightweight materials with complex cross-sectional shape. In porthole extrusion, the material flow is complex due to the complex structure of the die. Therefore, it is not easy to design an appropriate extrusion process. Magnesium alloy exhibits low deformability at temperatures below 200°C because of its hexagonal close-packed crystal structure. It also suffers from the problem of surface oxidation at temperatures above 400°C. Therefore, it is important to set the appropriate extrusion conditions. In this study, the porthole extrusion process for manufacturing automobile bumper back beams is designed. The influence of initial billet temperature, ram velocity, and nitrogen cooling system on the surface temperature of extruded magnesium alloy is investigated using FE analysis. First, the initiation temperature of surface oxidation is evaluated through extrusion test. Then, based on the FE analysis, the extrusion limit diagram is obtained considering the surface oxidation temperature and the extruder capacity. The effect of nitrogen cooling on surface temperature is investigated through coupled CFD and FE analysis. From the analyzed results and extrusion limit diagram, the initial billet temperature and ram velocity are determined. Finally, the effectiveness of the designed extrusion process is verified through an experiment.
| Original language | English |
|---|---|
| Pages (from-to) | 1423-1428 |
| Number of pages | 6 |
| Journal | International Journal of Precision Engineering and Manufacturing |
| Volume | 16 |
| Issue number | 7 |
| DOIs | |
| State | Published - 25 Jun 2015 |
Keywords
- CFD Analysis
- FE analysis
- Magnesium alloy
- Nitrogen cooling
- Porthole extrusion
- Process design