The most suitable aluminum for manufacturing automotive aluminum extrusions is 6061T6. This alloy is special, having been solution heat treated, quenched, cooled, and aged. The aging is done artificially to ensure that the aluminum alloy presents precipitation hardening according to specifications.

Since this alloy is in the 6xxx series, it has one of the best corrosion resistance. It also has fair machinability, cementing its candidacy for automotive aluminum extrusion applications.

For the economics of a project, aluminum 6061T6 is relatively cost-effective. Most manufacturers prefer it because it presents good properties at an affordable price. Even if an alloy such as 7075T6 aluminum is stronger, you will find most users going for 6061T6 based on cost.

It is also worth noting that even though 6061T6 may require a skilled welder, joining it is not so challenging. Surface finishing and painting the aluminum alloy is simple too.

For these main reasons, aluminum alloy extrusions manufactured from aluminum 6061T6 are the most popular in the automotive industry.