Patent ID: 7909229

Claim:
A method for joining materials comprising: overlapping a second material over a first material preliminarily formed with a joining hole so as to cover said joining hole; rotating and pressing a joining tool arranged in compliance with said joining hole onto the second material so as to locally soften and enter said second material in solid-phase state into the joining hole of the first material through frictional heat generated between said joining tool and said second material; pulling out said joining tool after a geometric engaging part is provided by said second material entered in said joining hole in relation with said first material; and allowing said engaging part to harden, thereby joining the first and second materials together, wherein the first material is preliminarily formed with a groove on an inner periphery of the joining hole, the groove extending for an entire length of the joining hole in a longitudinal direction of the joining hole, the engaging part being provided by a ridge on the second material formed through fitting the second material into said groove.