6 Nonferrous metals and their alloys; aluminium ingots; aluminium and its alloys; aluminium alloy ingots; semi-finished articles of unrefined aluminium; castings, foils, powder, and rolled, drawn or extruded semi-finished articles of aluminium or its alloys; iron and steel; metal materials for building or construction; prefabricated building assembly kits of metal; metal pulleys, springs and valves [not including machine elements]; metal junctions for pipes; tanks of metal; metal hardware; industrial packaging containers of metal.