Aluminium (or aluminium) is a chemical element in the boron group with symbol Al and atomic number 13. It is a silvery white, soft, ductile metal. Aluminium is a chemical element that has 8% from the weight of the earth's surface, this makes Aluminium the third most abundant element (after oxygen and silicon), and the most abundant metal, in the Earth's crust.Aluminium alloy used in the manufacturing of extruded doors and windows section shall correspond to wrought aluminium and aluminium alloy bars, rods and sections.