DS EN 2257:1997 Aerospace Series - Circular Tubes For Structures In Aluminium And Aluminium Alloys - Diameter 6 Mm <= D <= 100 Mm - Thickness 1 Mm <= A <= 6 Mm - Dimensions Defines dimensions and tolerances of circular tubes for structures in aluminium and aluminium alloys, of diameter 6 mm <= D <= 100 mm, thickness 1 mm <= a <= 6 mm, for aerospace applications.