Nippondenso Co., Ltd.

Tadashi Yamanaka

Keizo Takeuchi

Tatsuo Miura

Yoshio Iwai

A method of manufacturing mechanical parts from the raw material of metal scrap such as shavings and turnings of castings and steel and press chips of steel, includes the steps of: preparing the metal scrap including shavings and turnings; forming a billet by pressing metal scrap; heating the billet to the forging temperature, whereby a satisfactory plasticity is given to the billet for plastic deformation of metal scrap in the succeeding process; and forming the heated billet into a forged workpiece by use of a semi-closed forging die. The shape of the billet is determined such that, in this forging step, the respective portions of the billet are subjected to plastic deformation having a given plastic deformation rate, whereby material flow sufficient to generate metallic bond at the respective portions is caused, and burred portions are formed on portions of the forged workpiece mainly subjected to extrusion press during die-forging.

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Nagoya, Japan

Tadashi Yamanaka