Rivets and rivet manufacturing methods

A method of producing a fatigue resistant, fluid sealing, solid metal rivet comprising:

• providing an extrusion die, said extrusion die having
• a head portion defining a head cylindrical opening with a head diameter,
• a tapered portion defining a tapered opening extending from the head cylindrical opening, said tapered opening having a polished conical surface, and
• a shank portion defining a shank cylindrical opening extending from the tapered opening, said shank cylindrical opening having a polished shank cylindrical surface;
• providing a metal slug comprised of an aluminum alloy and having
• a slug cylindrical surface,
• a slug diameter approximately equal to the head diameter,
• a grain oriented substantially longitudinally along the axis of the metal slug, and
• a grain size of 6 or finer when measured in accordance with specification ASTM E 112;
• preprocessing the slug cylindrical surface to provide a surface that is substantially free of longitudinal surface defects;
• extruding the metal slug through the extrusion die from the head portion toward the shank portion to form a solid metal rivet having a head with the head diameter and a shank with the shank diameter connected by a tapered region;
• said solid metal rivet being characterized by a grain structure variation that is substantially the same along lines substantially parallel to the common axis of the head, the shank, and the tapered region, and by the surfaces of the shank and the tapered region being suitable for making a fluid tight assembly.

A method of producing a fatigue resistant, solid metal rivet comprising:

• providing an extrusion die, said extrusion die
• having a head portion defining a head cylindrical opening with a head diameter,
• having a tapered portion defining a tapered opening extending from the head cylindrical opening, said tapered opening having an included angle in a range of 30° to 90°, and
• having a shank portion defining a shank cylindrical opening extending from the tapered opening;
• providing a metal slug
• having a slug cylindrical surface,
• having a uniform slug diameter approximately equal to the head diameter, and
• having a grain oriented substantially longitudinally along the axis of the metal slug;
• extruding the metal slug through the extrusion die from the head portion, through the tapered portion, and into the shank portion to form a solid metal rivet having a head with the head diameter, a shank with a shank diameter, and connected by a tapered region;
• said solid metal rivet being characterized by a grain structure variation that is substantially the same along lines substantially parallel to the common axis of the head, the shank, and the tapered region.

A method of producing a fatigue resistant, solid metal rivet comprising:

• providing an extrusion die, said extrusion die
• having a head portion defining a head cylindrical opening with a head diameter,
• having a tapered portion defining a tapered opening extending from the head cylindrical opening, and
• having a shank portion defining a shank cylindrical opening extending from the tapered opening;
• providing a metal slug
• having a slug cylindrical surface,
• having a uniform slug diameter approximately equal to the head diameter, and
• having a grain oriented substantially longitudinally along the axis of the metal slug;
• extruding the metal slug through the extrusion die from the head portion, through the tapered portion, and into the shank portion to form a solid metal rivet having a head with the head diameter, a shank with a shank diameter, and connected by a tapered region;
• said solid metal rivet being characterized by a grain structure variation that is substantially the same along lines substantially parallel to the common axis of the head, the shank, and the tapered region.