Tenaris SA manufactures tubular steel products with assets in 16 countries. The company is controlled by Techint with a registration in Luxembourg and shares listed on the BIT (TEN), BMV(TS), and NYSE (TS) exchanges.
Dalmine began manufacturing seemless steel tubes in Italy in 1909, and Nippon Kokan Kabushiki (NKK) began the same practice in Japan in 1914. Agostino Rocca became a managing director at Dalmine in 1935 and founded Compagnia Tecnica Internazionale (Techint) in 1945. In 1954, Techint constructed the Tamsa plant in Mexico and the Siderca plant in Argentina while acquiring a controlling stake in Dalmine. Confab began to produce welded steel tubes in Brazil in 1960.
Siderca acquired Siat in 1986. Siderca acquired control Tamsa in 1993 and Dalmine in 1996, forming the alliance of Dalmine, Siderca, and Tamsa (DST). Siderca acquired Confab in 1999. In 2000, Siderca and NKK formed a joint venture for manufacturing seemless tubulars, and Siderca leased Algoma Steel's tubular plant.
The DST alliance was renamed Tenaris in 2001, and Tenaris SA was formed in 2002 to consolidate the holdings of Siderca, Tamsa, and Dalmine. Tenaris acquired Romania-based Silcotub in 2004. In 2006, the company acquired Maverick Tube, Prudential Steel, and Tubocaribe. Seamless Pipe Indonesia Jaya (SPIJ) was integrated in 2009.