1. 2) T.Satoh, S.Sakashita, T.Yashiki and M.Fukuda: Kobe Steel Eng. Rep., 55(2005), 48.
2. 3) T.Satoh and J.Suzuki: Kobe Steel Eng. Rep., 60(2010), 29.
3. 4) J.Imamura and Y.Tarutani: Nippon Steel & Sumitomo Met. Tech. Rep., 396(2013), 111(in Japanese); 106(2014), 108.
4. 5) M.Ueda, Y.Mori, M.Hashimoto, S.Yamamuro, S.Tanase, Y.Aoi, Y.Iwasa and S.Sakai: J. Jpn. Inst. Met., 71(2007), 545.
5. 6) M.Seido and O.Yoshioka: Titan. Jpn., 52(2004), 291.