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This paper presents the deformation behavior of commercial Mg-Al-Zn-Mn type alloys during hydrostatic extrusion process at elevated temperatures. In the current study commercial Mg-Al-Zn-Mn type alloys with different Al contents were subjected to hydrostatic extrusion process at a range of temperatures and at ram speeds of 4.5, 10 and 17 mm/sec. Under the hydrostatic condition at 518K, the alloy with Al contents of 2.9 wt% was successfully extruded at all applied speeds. The alloys with Al content of 5.89 and 7.86 wt% were successful up to 10mm/sec, and finally extrusion of alloy with Al content 8.46wt% was successful only at 4.5 mm/sec. These results show that the deformation limit in the Mg alloys in terms of extrusion speed greatly extended to higher value in the proximity of lower Al content. It is presumed that deformation becomes harder as Al content increases because of strengthening mechanism by solute drag to increase of supersaturated Mg 17 Al 12 precipitates. Also, microstructures of cast and extruded Mg alloys were compared. Defect-wide microstructure of cast alloy completely evolved into dense and homogeneous microstructure with equiaxed grains.

Experiments under a cold rotary swaging process have been conducted to investigate the dimensional characteristics of the swaged tube and solid bar for obtaining proper product of desirable quality. Dimensional characteristics are expressed in terms of dimensional deviation and surface roughness of swaged product through the rotary swaging process. The process variables such as forming speed and percent reduction of outer diameter of the product are considered and selected because of playing a key role in the rotary swaging process. Furthermore the developed rotary swaging machine with four-split dies, named as KRSM25, is used in the swaged experiment. Based on the experimental results, it is observed that the process variables affect the quality of swaged product such as dimensional precision, surface roughness of the product. Defect could be found to occur at a value of more than 2.0 mm/rev in forming speed. The dimensional precision of swaged product depends on the percentage reduction of outer diameter and forming speed. The work presented in this paper might be used for available information in the design of the optimum rotary swaging process.

The optimum design of a die shape for Pilger mill process was carried out using FEM analyses considering various processing factors. The important design parameters of the Pilger mill machine are feed rate and profile of the grooved die. Optimum design procedure was conducted in order to investigate effects on forming load and the deformed shape of a material depending on the die surface profiles. Profiles of the die surface for the optimum design were testified with linear, cosine and quadratic curves considering physical forming process. The results of the analyses provided that the model of the quadratic profile gave the lowest forming load and the proper deformed shape.