Known as the "aircraft alloy" in machining rod, this alloy has properties higher than 2017 and 2014. Though formability is generally considered only fair in the cold state, it is one of the most popular alloys for cold heading and roll threading applications. Can be machined to a high finish. Corrosion resistance is fair.

It is also the basic alloy for cold finished rectangular bar where strength and machinability are essential for precision fittings and parts.