1. Graduate School of Engineering, Osaka University 1 , Suita, Osaka 565-0871, Japan
2. Graduate School of Engineering, Osaka Sangyo University 2 , Daito, Osaka 574-8530, Japan
3. Joining and Welding Research Institute, Osaka University 3 , Ibaraki, Osaka 567-0047, Japan
4. National Institute of Technology, Ishikawa College 4 , Kahoku, Ishikawa 929-0392, Japan
5. Industrial Research Institute of Ishikawa Machinery and Material Division 5 , Kanazawa, Ishikawa 920-8203, Japan