Aluminum 6061 is one of the most widely used alloys in the 6000 series. This standard structural alloy, one of the most versatile of the heat-treatable alloys, is popular for medium to high strength requirements and has good toughness characteristics. Alloy 6061 has excellent corrosion resistance to atmospheric conditions and good corrosion resistance to seawater. This alloy also offers good finishing characteristics and responds well to anodizing; however, where cosmetic appearance is critical, consider the use of alloy 6063. For screw machine applications, alloy 6061 has adequate machinability characteristics in the heat-treated -T6/-T6511 condition. Chips from machining (particularly turning and drilling) can be difficult to break in the -T6/-T6511 temper condition. Chip breakers are recommended, and special machining techniques (i.e. peck drilling) can improve chip formation.