Method of manufacturing preform for connecting rod

摘要

A preform for a connecting rod of an engine is manufactured with a good productivity. The preform has a large-end mass portion which corresponds to a large-end portion of the connecting rod, a small-end mass portion which corresponds to a small-end portion thereof, and a shaft portion which corresponds to a rod portion thereof. There is manufactured a preform blank which has a shaft-shaped portion which is formed by extrusion. This shaft-shaped portion is made up of the shaft portion and an extended portion which extends axially forward from the shaft portion. The small-end mass portion is formed by squeezing the extended portion in the axial direction in a plurality of times starting with a portion near the shaft portion.