METHOD FOR PRODUCING FORGED CRANKSHAFT

• Main Authors: HORI, Masao, OKUBO, Junichi, TAMURA, Kenji, NAKANO, Ryusuke, YOSHIDA, Kunihiro, HWANG, Samsoo
• Format: Patent
• Language: English
• Published: 17.09.2020
• Subjects: MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES,RIVETS, BOLTS OR WHEELS; MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; PERFORMING OPERATIONS; PUNCHING METAL; TRANSPORTING

A production method includes a preforming process, a forming process and a finish forging process. In the preforming process, an intermediate preform is formed from a billet. In the forming process, while each of a plurality of rough journals of the intermediate preform is held and pressed vertically by a pair of holding dies, rough pins are decentered in directions perpendicular to the pressing direction by the holding dies and an axial direction of the intermediate preform, and the intermediate preform is pressed in the axial direction of the intermediate preform. In the finish forging process, a final preform is placed such that the directions in which the rough pins are decentered are parallel to a horizontal direction, and the thus placed final preform is pressed vertically by a pair of pressing dies. The production method reduces the risk of occurrence of seams on a forged crankshaft.