A Study on the Effect of Process Parameters to Mechanical Property in Forward Extrusion of Milli-size Cylindrical Pin

밀리 단위의 원형핀 전방압출에 있어서 공정인자가 기계적 성질에 미치는 영향 연구

The mechanical properties such as shear strength and the hardness of milli-size products that manufactured for various process parameters by forward extrusion using square dies are investigated. Shear strength test is implemented for the observation of relation between vickers hardness and shear strength in the interface of head and shaft part of a stepped pin. When the extrusion ratios of pure aluminum and pure copper billets increase, the hardness on both the surface and the center line of a pin also increase, especially the hardness on the surface is shown to be a little higher than on the center. The existence of knock-out pad in extrusion die caused hardness increase in the interface of a extruded pin. As compared shear strength with hardness of a pin, the approximated linear relations are suggested in this study.