The country’s first indigenous aircraft carrier, the 37,500-tonne ‘INS Vikrant’ which was launched on Monday and helped India to join the elite club of nations with the capability of designing and building a warship of this size and capability, has a strong Chhattisgarh connection as its steel plates were made in the State.
Defence Minister AK Antony’s wife Elizabeth launched the carrier at Kochi shipyard which is indeed an achievement that makes every Indian feel proud; more so for the people of Chhattisgarh because the specially toughened, warship-grade steel that has been used to construct the hull of the aircraft carrier warship, has been sourced from the Bhilai Steel Plant, the flagship unit of the public sector Steel Authority of India ltd (SAIl).
The plant is located in Chhattisgarh’s Bhilai in Durg district, roughly 30 km west from Raipur. “In fact, had Bhilai Steel Plant's technologists not accepted the challenge of developing the desired grade of special steel plates for the Indian Navy that were
hitherto being imported at steep prices, India's ambitious programme of indigenously building warships including aircraft carriers would never have taken off,” a statement of the plant said.
The successful development of DMR 249A steel plates by the Bhilai Steel Plant through normal route instead of costly and energy intensive quenching and tempering process has been a major achievement.
"Not only has it made possible for India to make the steel indigenously available for manufacture of Air Defence Ships and Corvettes by Indian Navy, it has saved the country huge expenditure in foreign exchange that would have been incurred, had the steel been imported,'' the statement of the plant added.
In fact, the special steel plates that Bhilai Steel Plant developed for the Indigenously-built Aircraft Carrier project in association with SAIl's research and development team and in collaboration with officials of India Navy and defence scientists of Defence Metallurgical Research laboratory (DMRl) and DRDO associated with the project, has
replaced various grades of steel plates and structural sections for naval warship applications that were being imported by Indian Navy.
Besides technologists from SAIl's RDCIS, a large dedicated team of the Bhilai Steel Plant officials from all the shops and departments in the production chain, namely the Quality Department, Blast Furnace, Steel Melting Shop II, Plate Mill as also from other units of SAIl have together achieved this feat.
Defence experts say that the DMR 249A is a micro-alloyed grade of steel with stringent toughness requirement at sub-zero temperature and mechanical properties as specified by naval architecture engineers.
The Bhilai Steel Plant had embarked upon developing DMR 249A grade steel plates through normal route, instead of Quenching and Tempering route being followed in case of steel procured from imported source. The heats were made through Converter-Continuous Casting route with secondary refining to produce steel with required chemistry.
The steel was further treated and the slabs were fully conditioned and rolled into plates of desired at Bhilai's Plate Mill. On successful production of plates, the thickness range was further enhanced. All plates were rolled in normalised condition only so as to achieve consistent properties. Inspection, testing and certification were carried out by the inspection wing of Indian Navy. Internal soundness of the plates and mechanical properties as revealed by ultrasonic testing were found to be excellent and as per specified requirements.