| Name | Address | Phone |
| Aichi Steel Corporation | 1, Wanowari, Arao-machi, Tokai-shi, Aichi-ken 476-8666 | 052-604-1111 |
| Daido Steel Co., Ltd. | 1-1-10, Higashisakura, Higashi-ku, Nagoya-shi, Aichi-ken 461-8581 | 052-963-7501 |
| JFE Steel Corporation | 2-2-3, Uchisaiwaicho, Chiyoda-ku, Tokyo 100-0011 | 03-3597-3111 |
| Kobe Steel, Ltd. | 5-9-12, Kitashinagawa, Shinagawa-ku, Tokyo 141-8688 | 03-5739-6000 |
| Kubota Corporation | 3-1-3, Nihonbashi-Muromachi, Chuo-ku, Tokyo 103-8310 | 03-3245-3111 |
| Mitsubishi Steel Mfg. Co., Ltd. | 3-2-22, Harumi, Chuo-ku, Tokyo 104-8550 | 03-3536-3111 |
| Nakayama Steel Works, Ltd. | 1-1-66, Funamachi, Taisho-ku, Osaka-shi, Osaka 551-8551 | 06-6555-3111 |
| Nippon Steel Corporation | 2-6-1, Marunouchi, Chiyoda-ku, Tokyo 100-8071 | 03-6967-4111 |
| Nisshin Steel Co., Ltd. | 3-4-1, Marunouchi, Chiyoda-ku, Tokyo 100-8366 | 03-3216-5511 |
| Sanyo Special Steel Co., Ltd. | 3007, Nakashima, Shikama-ku, Himeji-shi, Hyogo-ken 672-8035 | 079-235-6003 |
| Sumitomo Metal Industries, Ltd. | 1-8-11, Harumi, Chuo-ku, Tokyo 104-6111 | 03-4416-6111 |
| The Japan Steel Works, Ltd. | 1-11-1, Osaki, Shinagawa-ku, Tokyo 141-0032 | 03-5745-2001 |
| Topy Industries, Ltd. | 1-2-2, Osaki, Shinagawa-ku, Tokyo 141-8634 | 03-3493-0777 |
| Toyo Kohan Co., Ltd. | 2-12, Yonbancho, Chiyoda-ku, Tokyo 102-8447 | 03-5211-6200 |
| Yodogawa Steel Works, Ltd. | 4-1-1, Minamihonmachi, Chuo-ku, Osaka-shi, Osaka 541-0054 | 06-6245-1111 |
