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Technology
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BrahMos Missile                              respectively. All these five aluminium   not have the expertise of producing
                                             alloys had to be indigenised to match    three out of the five Russian grade
   BrahMos is a supersonic cruise            the Russian GOST specifications.         aluminium alloys as mentioned.
missile that can be launched from                                                     BrahMos Aerospace Private Limited
multiple platforms. It is a joint venture       The materials were earlier being      (BAPL), therefore, relied upon DMRL,
between Russian Federation’s NPO             procured from NPOM, Russia               having decades long laboratory
Mashinostroyeniya (NPOM) and                 who in turn used to procure them         scale R&D experience together with
India’s DRDO. The missile reaches            from multiple sources resulting in       varying levels of industrial experience,
a maximum speed of 2.8 Mach                  issues involving quality, time and       for developing and producing the
(i.e., 2.8 times the velocity of sound). At  cost overruns. The cost calculations     aluminium alloys at the industrial
this speed, the selection of aluminium       carried out in the year 2010 revealed    scale for BrahMos missile applications.
alloys that are used in the bulk of the      that the total cost of imported
missile is very important.                   aluminium alloys required per missile       Under DMRL’s technical
                                             is about three times the cost of such    guidance, a team of engineers from
   Five different Russian grades of          alloys when produced by the Indian       BAPL, Hyderabad, prepared the
wrought aluminium alloys, i.e., 1201,        industries. This together with the fact  Quality Assurance Plans (QAPs) for
AK4-1Ч, AMΓ6, AK6 & Д16Ч are                 that a significant number of BrahMos     production of ingots and various semi-
utilised in different parts of the missile   missiles was then already ordered by     products. Such QAPs described the
in eight different semi-product forms,       the Indian armed forces formed the       process flow chart of individual alloys,
i.e., sheet and plate (with and without      basis for taking up the indigenisation   ingot qualification check criteria,
cladding), forging, rod, pipe, tube,         work of these aluminium alloys.          thermal and mechanical processing
rolled ring and profile in a variety of                                               parameters, quality check details
heat treatment conditions, i.e., O, T31,        At the time the work was taken        of the final products that include
T4, T6, T81, T83, T851, T852 and T87.        up (in 2010), it was noted that there    the targeted mechanical properties,
It is noteworthy that the alloys 1201,       was hardly any industry in the           dimensional tolerances and ultrasonic
AK4-1Ч and Д16Ч are the Aluminium            country having necessary expertise       quality.
Association (AA) specification               for downstream processing of these
equivalent of AA2219, AA2618                 aerospace grade wrought aluminium           DMRL played a crucial role in the
and AA2124 alloys, whilst, alloys            alloys. Further, although, Hindalco      selection of the production agencies.
AMΓ6 and AK6 have no Aluminium               Almex Aerospace Limited (HAAL),          The alloy ingots in the form of billets
Association specification equivalents.       Aurangabad had the expertise of          were produced in HAAL for all the
These two alloys are described               producing high strength, aerospace       alloys. The ingots in the form of slabs
here as BAPL5xxx and BAPL2xxx,               grade aluminium alloy billets, it did    and the resultant sheets and plates
                                                                                      were produced at BALCO, Korba
Production agencies responsible for indigenisation of aluminium                       for selected alloys with and without
                         alloys for BrahMos missile                                   cladding. The ingots in the form of
                                                                                      billets and the resultant extrusions
                                                                                      (/rods) of larger sizes were produced in
                                                                                      OFAJ, Nagpur for alloy AA2219, and
                                                                                      the extrusions of smaller sizes together
                                                                                      with the forging stocks were produced
                                                                                      in Century Extrusions Limited
                                                                                      (CEL), Kharagpur for alloys AA2219,
                                                                                      AA2124, AA2618 and BAPL5xxx. The
                                                                                      rolled rings were produced in CHW
                                                                                      Forge Private Limited (CHW Forge),
                                                                                      Greater Noida for alloys AA2219,
                                                                                      AA2618 and BAPL5xxx. The forgings
                                                                                      were produced at Steel and Industrial
                                                                                      Forgings Limited (SIFL), Thrissur for
                                                                                      alloys AA2219, AA2618, BAPL2xxx
                                                                                      and BAPL5xxx. The seamless pipes
                                                                                      and tubes were produced at Nuclear
                                                                                      Fuel Complex (NFC), Hyderabad
                                                                                      for the alloy BAPL5xxx. Later,

4 January-February 2018                      Aluminium Alloy Technologies for Advanced Defence Systems
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