What is the primary purpose of rivets in sheet metal assemblies?

Rivets serve a fundamental role in sheet metal assemblies by providing a mechanical connection that securely joins two or more metal parts together. When installed properly, rivets create a strong, permanent bond that can withstand various stresses and loads, making them ideal for applications where structural integrity is critical. The rivet's design allows it to deform upon installation, expanding and firmly gripping the materials being joined, which enhances the connection strength.

The other choices do not accurately reflect the primary function of rivets. For instance, while surface decoration and painting can enhance the aesthetic appeal of metal parts, they do not describe the operational purpose of rivets. Similarly, rivets are not used to separate metal sheets during installation; rather, they serve to keep them connected and stable. Understanding the true purpose of rivets helps clarify their importance in the construction of reliable and durable sheet metal structures.