6061 and 6063 are the two most common extrusion alloys.
- 6061 Aluminum: Known as “structural alloy.” It has higher strength and toughness (Tensile Strength: 45 ksi T6 vs. 35 ksi for 6063-T6). It has better machinability. It is slightly more difficult to extrude, limiting maximum complexity and thinness. Typical applications: High-stress structural parts, truck frames, marine components, machinery, and platforms where strength is paramount.
- 6063 Aluminum: Known as “architectural alloy.” It has superior extrudability, allowing for more complex, thinner, and smoother-finish profiles. It has excellent corrosion resistance and responds very well to anodizing, producing a bright, clear finish. It is weaker than 6061. Typical applications: Window/door frames, curtain walls, furniture, aesthetic trim, and most heat sinks where form and surface finish are key.
Summary: 6061 for strength, 6063 for form and finish.