Forging of Long Hollow Shafts of Hard-to-Form Material by Hollow Shaft Extrusion after Piercing with Back Pressing

후방 가압식 피어싱 및 중공축 압축 공법에 의한 난성형 재료 중공장축의 단조

We presented a special method of forging hollow shafts of hard-to-form material, which is composed of piercing with back pressing and hollow shaft extrusion. The presented method was applied to cold forging a bushing of an excavator. The finite element simulation technology was employed for developing the optimized process and the predictions were compared with the experiments. The method was also applied to an automotive part and was verified to be powerful for manufacturing the cold forged hollow shafts of the hard-to-form materials.