c-g-designs

METALS .

            THE LIGHT METAL ALLOYS.

            The aluminium (aluminum fir the americans) alloys have a 4 digits denomination are divided in classes corresponding to the mail addition :

            -1000 = pure  aluminium . (1050=99,50%Al),

            -2000 = aluminium/copper  (2017 (extruded and rolled semi-products). This alloy is typically french (duralumin®).

            -3000= alumium/manganese.

            -4000= aluminium/silicium.

            -5000= aluminium/magnesium.

            -6000= aluminium/magnesium/silicium.

            -7000= aluminium/zinc (7075 extruded or rolled semi-products).

            -8000= réserved .

            Aluminium and its alloys can be delivered under different metallurgical condittions, also depending of the classes : O(annealed), H (Hammer-Hardened), T(Quenched), W (quenched but not stabilised).

            Only the ‘T’ alloys of the 6000 and 7000 series are of interest for us :

                        -6061 T651, Rm= 29kgs/mm², dureté HB=88.

                        -7075 T651, Rm=59kgs/mm², dureté HB=163.

            The 6061  in T6 condition (named Aircraft Aluminum in USA) is used  for static elements (trigger guards, stock components, scope rails).

            The 7075 T6, with eventually the necessary hardened steel inserts, find its use for receivers and certain mechanical parts. Its low mass,almost 1/3 of the steel, is a strong point (2,8 for the steel 7,8).

            The light metal alloys can receive an anodic oxydation process, leaving a layer of extremely hard  oxyde (alumine) who can take several forms :

            -Decorative anodising who can be coloured in final phase.

            -Hard anodising, leaving a thick and extremely hard layer having all the required mechanical properties. Colours are most often goldish or black.

            R.G.C