ROTARY TOOL, AND TREATING METHOD AND SURFACE TREATMENT METHOD OF MEMBER USING THE ROTARY TOOL

摘要

PROBLEM TO BE SOLVED: To prevent any non-filled defect by increasing the effect of pressing a base metal structure in plastic flow by the friction stirring and joining operation into a stock. SOLUTION: A protruded part 2 and a shoulder part 3 of a rotary tool 4 are formed of a steel such as tool steel and stainless steel of the hardness higher than that of an aluminum alloy, and a spiral groove 2a of the predetermined pitch is formed on an outer circumferential part of the protruded part 2. A spiral groove for guiding the base metal structure in plastic flow by the friction heat by the rotation of the tool into the protruded part 2 in a center part while pressing the base metal structure inside the stock is formed in an end face in contact with the work surface at the shoulder part 3, and the depth of the spiral groove becomes shallower toward a root part to the shoulder part 3 at the protruded part 2.