METAL MATERIAL PROCESSING METHOD, STRUCTURE PROCESSED USING METAL MATERIAL PROCESSING METHOD AND ROTARY TOOL

摘要

In a metal material processing method, two metal materials are arranged to face each other in a processing portion, and a distal end of a rod-shaped rotary tool is inserted into the processing portion while rotating the rotary tool, thereby the two metal materials are processed. The distal end of the rotary tool has a probe protruding in a central portion and a shoulder in a peripheral portion. The probe and the shoulder are constituted by different materials in at least surface portions that are in contact with the metal materials.