ENLARGEMENT PROCESSING METHOD FOR WORKPIECE

摘要

Provided is an enlargement processing method for a workpiece wherein a portion of a workpiece such as a shaft member can be processed stably into an enlarged portion while a driving force required for the formation of the enlarged portion can be reduced. In the enlargement processing method for a workpiece, the internal energy of the workpiece (W) is increased by applying a compressive force, for generating a compressive stress equal to or higher than the initial yield strength, to the workpiece, a part of the increased internal energy of the workpiece (W) is decomposed by applying, in the transverse direction, alternating shear energy for confining the deformation of the workpiece (W) to within the limit of elasticity, and the enlargement-scheduled region of the workpiece (W) is deformed and enlarged with the assistance of the decomposed energy, thus forming an enlarged portion on the workpiece (W).