What does the installation of an MS20470D rivet require for optimal strength?

The installation of an MS20470D rivet requires aging after installation for optimal strength. Aging refers to the process of allowing the rivet material to reach its peak mechanical properties through a time-dependent reaction in the material. This is particularly significant for aluminum alloys that undergo heat treatment to enhance their strength.

The aging process helps in achieving the required hardness and tensile strength that contribute to the overall structural integrity of the aircraft. By letting the rivet age, it can develop better resistance to stress and fatigue, which are critical in an aerospace application where components must withstand various and often extreme loads during flight.

In contrast, while immediate installation might seem efficient, it does not allow for optimizing the rivet's mechanical properties, and mere alignment, although necessary, does not ensure strength without the aging process. Additionally, a cooling period is not relevant or required for the installation of these rivets, as aging is about time rather than temperature adjustments after installation.