With many tradesmen referring to aluminum angle as “L Bracket”, architectural aluminum angle and structural aluminum angle, “channel” or other terms, it can be confusing to a purchasing agent to know what exactly it is that you are ordering. The first difference between architectural aluminum angle and structural aluminum angle is the profile that is extruded. Architectural angle has a constant thickness throughout the piece with a sharp 90 degree angle on the outside and inside where the two legs meet and is a constant thickness to the very end of the piece.
Structural aluminum angle on the other hand has a radius on the inside corner where the two legs meet and a sharp 90 degree angle on the outside. In addition, its legs are tapered at the outside with a radius. See the detail pictures at the right for the difference.
Aside from the shape, they are also made of different alloys of aluminum and can have different heat treatment finishes.
Architectural Aluminum Angle is made from 6063 Series Aluminum where the main alloying elements are Magnesium (0.45% – 0.9%) and Silicon (0.2% – 0.6%). 6063 Alloy aluminum angle is often finished with a T6 or T52 treatment. A T6 Temper means that the extrusion is solution heat treated and artificially aged. A T52 Temper means that the extrusion is cooled from an elevated temperature shaping process and artificially aged. The Temper affects the mechanical properties of the end product. 6063-T6 has a tensile strength of 25,000 psi and a yield strength of 25,000 psi. The 6063 alloy has a smooth finish that is conducive to finishing or anodizing.
Structural Aluminum angle is made from 6061 Series Aluminum where the main alloying elements are Magnesium (0.4% – 1.2%) and Silicon (0.4% – 0.8%). It is common to for 6061 series alloy products to have a T6 Temper. 6061-T6 temper has a tensile strength of 42,000 psi and a yield strength of 35,000 psi.