| 1978-05 |
Osaka Steel Co., Ltd. was established as the parent company of the merger between Dai Iron Industry Co., Ltd. and Yamato Steel Co., Ltd. |
| 1978-05 |
OSAKA STEEL CO., LTD. was established in preparation for the merger of Daitetsu Steel Industrial Co., Ltd. and Yamato Steel Co., Ltd. |
| 1978-10 |
The two companies were absorbed and merged, and business operations commenced. |
| 1978-10 |
OSAKA STEEL CO., LTD. acquired the two companies and commenced operation. |
| 1980-10 |
Absorbed and merged with Nippon Steel Machinery Co., Ltd., and the company's factory was relocated to Tsumori Factory to become a processing products factory. |
| 1980-10 |
Acquired NITTETSU KOKI CO., LTD. and relocated its plant to Tsumori Works as a processing plant. |
| 1980-11 |
Established a subsidiary, Osaka Bussan Co., Ltd. |
| 1980-11 |
Established Osaka Bussan Trading Co., Ltd. as a subsidiary. |
| 1981-02 |
Established a subsidiary, Osaka New Transport Co., Ltd. |
| 1981-02 |
Established Osaka Shin Unyu Co., Ltd. as a subsidiary. |
| 1987-09 |
Established subsidiary Japan Steel Co., Ltd. |
| 1987-09 |
Established Nihon Steel Co., Ltd. as a subsidiary. |
| 1989-03 |
Acquired management rights of West Japan Steel Co., Ltd. |
| 1989-03 |
Acquired the management rights to Nishi-Nippon Steel Co., Ltd. |
| 1990-03 |
Became a subsidiary of Nippon Steel Corporation (now Nippon Steel Corporation) through third-party allotment of shares. |
| 1990-03 |
Reorganized as a subsidiary of Nippon Steel Corporation (presently Nippon Steel Corporation) following capital increase by allotment of new shares to third parties. |
| 1994-12 |
Listed on the Second Section of the Osaka Securities Exchange. |
| 1994-12 |
Listed on the Second Section of the Osaka Stock Exchange. |
| 1995-06 |
Merged with West Japan Steel Co., Ltd., and its factory was renamed West Japan Steelworks (now West Japan Kumamoto Factory). |
| 1995-06 |
As a result of the merger, Nishiko Logistics Co., Ltd. became a subsidiary. |
| 1995-06 |
Merged with Nishi-Nippon Steel Co., Ltd., naming its plant Nishi-Nippon Works (presently Nishi-Nippon Kumamoto Works); acquired NISHIKO U TRANSPORT SERVICE CO., LTD. as a subsidiary as a result of the merger. |
| 1995-06 |
Absorbed and merged with Nishi-Nippon Steel Co., Ltd., and the company’s factory became Nishi-Nippon Steelworks (now Nishi-Nippon Kumamoto Factory). As a result of the merger, Nishi Steel Logistics Co., Ltd. became a subsidiary. |
| 1996-11 |
Listed on the Second Section of the Tokyo Stock Exchange. |
| 1996-11 |
Listed on the Second Section of the Tokyo Stock Exchange. |
| 1997-09 |
Transferred to the First Section of the Tokyo and Osaka Securities Exchanges. |
| 1997-09 |
Listing transferred to the First Section of the Tokyo Stock Exchange and the Osaka Stock Exchange. |
| 1998-10 |
Started commercial operation at Tsumori Rolling Mill, Second Rolling Mill, and Sakai Rolling Mill, which consolidates the Tsumori and Second Rolling Mills. |
| 1998-10 |
Started operation of a rolling mill at Sakai integrating Tsumori and Dai-ni rolling mills. |
| 1999-03 |
Established a subsidiary, Shin-Hokkai Steel Co., Ltd. |
| 1999-03 |
Established Shin-Hokkai Steel Co., Ltd. as a subsidiary. |
| 1999-10 |
Merged with Kansai Billet Center Co., Ltd., and its factory was renamed Sakai Steel Factory. |
| 1999-10 |
Acquired Kansai Billet Center Co., Ltd. and named its steelmaking plant Sakai Works. |
| 2002-03 |
Obtained ISO 9001 certification at Osaka Steel Enkashima Factory (now Osaka Business Office Enkashima Factory) and Sakai Factory (now Osaka Business Office Sakai Factory). |
| 2002-03 |
Acquired ISO9001 certification for Osaka Steel’s Okajima Works (presently Osaka Unit Okajima Works) and Sakai Works (presently Osaka Unit Sakai Works). |
| 2002-03 |
Obtained ISO9001 certification at Osaka Steel’s Unkashima Factory (now Osaka Business Office Unkashima Factory) and Sakai Factory (now Osaka Business Office Sakai Factory). |
| 2003-04 |
Obtained ISO 9001 certification at Osaka Steel West Japan Steelworks (now West Japan Kumamoto Factory). |
| 2003-04 |
Acquired ISO9001 certification for Osaka Steel’s Nishi-Nippon Works (presently Nishi-Nippon Kumamoto Works). |
| 2003-04 |
Obtained ISO9001 certification at Osaka Steel’s Nishi-Nippon Steelworks (now Nishi-Nippon Kumamoto Factory). |
| 2003-11 |
Obtained ISO 14001 certification at Osaka Steel Co., Ltd. |
| 2003-11 |
Acquired ISO14001 certification for Osaka Steel Co., Ltd. |
| 2003-11 |
Obtained ISO14001 certification at Osaka Steel Co., Ltd. |
| 2005-01 |
Fully acquired Japan Steel Co., Ltd. |
| 2005-01 |
Reorganized Nihon Steel Co., Ltd. as a wholly-owned subsidiary. |
| 2012-12 |
Established a joint venture PT. Krakatau Osaka Steel (KOS) in Banten Province, Indonesia, with Indonesia's state-owned steel company PT. Krakatau Steel (Persero) Tbk. |
| 2012-12 |
Jointly established PT. KRAKATAU OSAKA STEEL (KOS) with state-run company PT. KRAKATAU STEEL (Persero) Tbk. in Cilegon, Banten Province, Indonesia. |
| 2014-03 |
Dissolved the subsidiary Shin-Hokkai Steel Co., Ltd. |
| 2014-03 |
Dissolved the subsidiary Shin-Hokkai Steel Co., Ltd. |
| 2014-09 |
Finalized a joint venture agreement with Krakatau Steel for manufacturing and sales of small and medium-sized shaped steel, rebar, and flat steel in Indonesia. |
| 2014-09 |
Concluded a final agreement on the joint manufacturing and sales operation of medium/small steel and iron reinforcing bars and flat bars with PT. Krakatau Tbk. |
| 2016-03 |
Made Tokyo Steel Co., Ltd. a subsidiary through a tender offer. |
| 2016-03 |
Suspended steelmaking processes at Osaka Steel Osaka Enkashima Factory (now Osaka Business Office Enkashima Factory) and transferred all steel source (steelmaking process) to Sakai Factory (now Osaka Business Office Sakai Factory). |
| 2016-03 |
Acquired Tokyo Kohtetstu Co., Ltd as a subsidiary in the Tender Offer. Suspended production of a steelmaking process of Osaka Okajima Works (presently Osaka Unit Okajima Works), and transferred its production to a steelmaking process of Sakai Works (presently Osaka Unit Sakai Works). |
| 2016-03 |
Made Tokyo Steel Co., Ltd. a subsidiary through a tender offer. Ceased the steelmaking process at Osaka Steel’s Osaka Unkashima Factory (now Osaka Business Office Unkashima Factory) and transferred all steel sources (steelmaking process) to Sakai Factory (now Osaka Business Office Sakai Factory). |
| 2017-01 |
PT. Krakatau Osaka Steel commenced sales and production. |
| 2017-01 |
PT. Krakatau Osaka Steel started commercial production. |
| 2017-04 |
Established the Osaka Business Office overseeing the Osaka Onkashima Factory and Sakai Factory, renamed Osaka Onkashima Factory to Osaka Business Office Onkashima Factory and Sakai Factory to Osaka Business Office Sakai Factory. |
| 2017-04 |
Set up the Osaka Unit, which supervises Osaka Okajima Works and Sakai Works, and renamed Osaka Okajima Works as Osaka Unit Okajima Works, and Sakai Works as Osaka Unit Sakai Works. |
| 2021-08 |
Absorbed and merged the subsidiary Japan Steel Co., Ltd., and made its factory the Kishiwada Factory. |
| 2021-08 |
Acquired Nihon Steel Co., Ltd and named its plant Kishiwada Works. |
| 2022-04 |
Transitioned to the Standard Market following a review of the market classification of the Tokyo Stock Exchange. |
| 2022-04 |
Transferred to the Standard Market in conjunction with restructuring of Tokyo Stock Exchange’s market segments. |
| 2022-04 |
Transferred to the Standard Market in conjunction with restructuring of Tokyo Stock Exchange’s market segments. |
| 2022-09 |
Stopped the rolling process at Osaka Business Office Onkashima Factory and transferred production to Osaka Business Office Sakai Factory. |
| 2022-09 |
Stopped the rolling process at the Osaka Unit’s Okajima Works and transferred the production to the Unit’s Sakai Works. |
| 2022-12 |
Dissolved Osaka Bussan Co., Ltd. |
| 2022-12 |
Dissolved Osaka Bussan Trading Co., Ltd. |
