What type of rivet head is hot-formed to exert high compressive forces?

The correct answer is that the hot-formed rivet head is designed specifically to exert high compressive forces. This is a result of the hot-forming process, which involves heating the metal to a certain temperature before shaping. This technique allows for better malleability and ductility of the material, enabling it to deform more easily under compression when the rivet is set.

In applications where high-strength joints are required, the hot-formed rivet head can create a tight fit and solid bond between the materials being joined. This is particularly important in structural applications, like in bridges or buildings, where the integrity of the connection is critical for handling loads and stresses.

Other types of rivet heads, such as flat heads, serve different purposes and may not be specifically designed for exerting high compressive forces. Flat heads are generally used for aesthetics or to minimize protrusion, and while they can secure joints, they generally do not focus on high compressive strength the way a hot-formed rivet head does.

By understanding the role of different rivet heads and their formation methods, one can appreciate why the hot-formed rivet head is uniquely suited for applications requiring robust compressive strength.