Arjun Mk.2 MBT Now A Firm Reality
Contrary to widespread speculation, the Indian Army (IA) has not forsaken or given up on the Arjun Mk.2 main battle tank (MBT). Instead, for the past four years, the IA’s Directorate General of Mechanised Warfare has been overseeing a collective developmental effort involving the DRDO, and the MoD-owned defence public-sector undertakings and private-sector OEMs that will in the near future result in a fully-loaded 60-tonne MBT armed with a 120mm smoothbore cannon while retaining the existing 1,400hp powerpack.
Under the supervision and guidance of the DRDO’s Avadi-based Combat Vehicles Research & Development Establishment (CVRDE), and with the help of the MoD’s Directorate General of Quality Assurance (DGQA) and the IA’s Corps of Electronics & Mechanical Engineers (EME), a number of key decisions have been to achieve a weight reduction of 8 tonnes in the existing design of the 68-tonne Arjun Mk.1A MBTs, 118 of which are now in delivery.
For starters, the baseline hull of the Arjun Mk.2 will no longer be built with imported low-carbon, nickel-chromium-molybdenum rolled homogeneous armor (RHA) steel, but with lighter high-nitrogen steel (HNS) whose production technology has been mastered by the DRDO’s Hyderabad-based Defence Metallurgical Research Laboratory (DMRL) and has been transferred to Jindal Stainless Steel Ltd (Hisar). HNS will also be used by TATA Motors Ltd for producing the 83 Kestrel 8 x 8 armoured personnel carriers already on order.
HNS is produced in a four-step process: primary melting of the steel can carried out in either induction furnace or electric arc furnace by using appropriate raw materials; secondary melting can be carryout in by nitrogen gas-purging in to the metal; under ladle refining, ferro-nitrates are added to molten metal for obtaining final nitrogen content in the alloy if it is required and hot-rolling is carried out in a single heat, without reheating. Minimum percentage of reduction should not be less than 75% of the slab thickness. To be placed in strategic locations in both the hull and turret will be the DRDO-developed ‘Kanchan’ ceramics-basedcomposite laminate armour tiles as well as indigenously-built explosive reactive armour (ERA) tiles developed by the DRDO’s High Energy Materials Research Laboratory (HEMRL) on the front and sides of the hull and turret sections.
To ensure optimal weight budgeting during the production engineering stage, the CVRDE has contracted Dynamatic Technologies Ltd, which specialises in complex, five-axis robotic machining, as well as in converting two-dimension paper blueprints into three-dimension computer model that are more precise, and have tighter tolerances. Digitising the drawings creates a baseline configuration for greater accuracy. This in turn streamlines manufacturing, since conventionalmanufacturing based on two-dimensional paper blueprints tend to leave tiny gaps between the different components of an assembly that were filled with shims, leading to increased weight. But by digitising blueprints, those tiny gaps can be entirely eliminated during the manufacturing process.
Under another weight-reduction exercise, the CVRDE has contracted the Alicon Group for building all-aluminium road-wheels and ventilators for not only the Arjun Mk.2, but also for the IA’s existing upgraded T-72CIA medium tanks. They will replace the all-steel road-wheels built bySundaram Industries for the Arjun Mk.1A. Similarly, TATA Power SED has been contracted for producing all-electric turret stabilisation/traverse systems, in place of the existing electro-hydraulic system.
Improvements have also been made to the 1,400hp powerpack (comprising the MTU 838 Ka-501 diesel engine and RENK’s RK-304S gearbox) through the usage of indigenously developed cooling systems.
However, the area that will see the Arjun Mk.2 emerging as a true new-generation MBT will be vectronics, and in particular the battlespace management system (BMS), which has been designed to operate at the unit-level and below, and which will synthesise the battlespace situational awareness picture for the unit commander, whether it be a mechanised infantry regiment or an armoured regiment. The MBT and selected infantrymen will thus become situational awareness platforms.
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