This 6061 aluminum meets ASTM B221 specifications.
6061 aluminum is a lightweight, general-purpose aluminum alloy that can easily be machined or welded..1-1/2" x 1-1/2" Aluminum Angle 6061, 2" Length, T6511 Mill Stock, 1/4" Thick It has a high resistance to corrosion, and an excellent weight-to-strength ratio.