Steel Authority of India Limited is an Indian public sector steel manufacturing corporation based in New Delhi designated as Maharatna CPSE. It is the largest government-owned steel producer, with an annual production of 18.29 million metric tons. Incorporated on 24 January 1973, SAIL has 50,001 employees and is under the administrative control of the Ministry of Steel. SAIL operates and owns five integrated steel plants at Bhilai, Rourkela, Durgapur, Bokaro and Burnpur and three special steel plants at Salem, Durgapur and Bhadravathi. It also owns a Ferro Alloy plant at Chandrapur. It also has an R&D Centre for Iron & Steel and a Centre for Engineering in Ranchi, Jharkhand. The company has a total of 692 patents globally, out of which 343 have been granted. More than 64% of the 692 patents are active. SAIL has filed the maximum number of patents in India, followed by Egypt and Germany. Wikipedia