A method for sizing a junction section by orbital friction welding between a blade and a stub of a bladed disk for a turbomachine. The section is sized such that the ratio of an average ray length extending fully into the section from a point at the periphery of said section and sweeping across said section, where said average ray length is a maximum average length, and an average length of rays extending completely into the section from another point at the periphery of said section and sweeping through said section, where said average length is a minimum average length, is less than or equal to 2.