| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacturing a forged crankshaft capable of reliably suppressing the movement of a center of gravity that occurs to the forged crankshaft at a time of trimming.SOLUTION: A method of manufacturing a forged crankshaft 1 comprises: a finishing step (S14) of obtaining a finished molded piece 104 by die forging using a finishing die; and a trimming step (S15) of trimming the finished molded piece 104 using a trimming die 20 that includes a punch 21 and a die 22, and obtaining the forged crankshaft 1 that includes arm portion 3 and counterweight portions 5, the punch 21 being replaced with a punch in which an offset portion 24 that is a concave portion offset from a shape of the forged crankshaft 1 is formed in a region of a die inner surface 21a of the punch 21 abutting on the counterweight portions 5 if the number of executing the finishing steps (S14) reaches a predetermined number A. |
