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Table 2. Heat Treatment Conditions (/Tempers) of the Indigenised Aluminium Alloys

Heat Treatment            Description                                                  Aluminium Alloy,
Nomenclature                                                                         Semi-Product Form

F or M          As-fabricated or as-manufactured                     DMR291A (a modified composition of AA5086),
                                                                     plate

O               Annealed                                             AA6082, Extrusion; AA2219, Sheet and Plate;
                                                                     BAPL 5xxx, rod, forging, rolled ring, plate, profile,
H24                                                                  pipe and tube; AA6082, tube
T31
T4              Strain hardened (half hard) and partially annealed   DMR291A, Sheet
T451
                Solution treated, cold worked and naturally aged     Alclad AA2219, Sheet
T6
T651            Solution treated and naturally aged                  AA2124, Profile

T7X51           Solution treated, stress relief by stretching and naturally Alclad AA2219, Sheet
                aged

                Solution treated and artificially aged               AA2618 & BAPL 2xxx, Forging and Extrusion

                Solution treated, stress relief by stretching and    AA6082, Extrusion; AA6061, Sheet
                artificially aged

                Solution treated, stress relief by stretching and    RDE40M, Sheet and plate
                stabilised by overaging                              DMR7xxx, Flat and forging

T81             Solution treated, cold worked and artificially aged  Alclad AA2219, Sheet

T83             Solution treated, cold worked and artificially aged  Alclad AA2219, Sheet

T851            Solution treated, cold worked by stretching and      AA2219, Extrusion
                artificially aged

T852            Solution treated, cold worked by compression and AA2219 & AA2618 & AA2124, Rolled Ring
                artificially aged

T87 Solution treated, cold worked (a minimum of 7 % but Unclad AA2219 and Alclad AA2219, Plate
                             not exceeding 8 %) and artificially aged

   Note: Tx51, i.e., stress relief by stretching (1-3 %), Tx511, i.e., minor straightening after stretching and Tx52, i.e., stress
relief by compression (1-5 %) are applicable for various tempers, where x = 3, 4, 6, 7 and 8, whichever is applicable. Stress relief
by either stretching or compressing is provided following solution treatment. The exact details of the heat treatments utilised
to obtain reproducible and improved properties in the indigenised materials are proprietary in nature.

Aluminium Alloy Technologies for Advanced Defence Systems            	 January-February 2018 19
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