Stress-Strain State of Forming Tools during Cold Heading of Aluminum Alloy Rivets

Abstract

This study investigates the stress-strain state of forming tools during the cold heading of rivets manufactured from A1050 commercial aluminum, A5056 aluminum alloy, and high-strength A2024 Al-Cu-Mg alloy. Particular attention is given to the influence of interference fit between the punch, die, and die sleeve on stress distribution within the tooling system. The cold heading process was analyzed using the finite element method (FEM), and the numerical predictions were validated through experimental measurements. Good agreement was obtained between the simulation and experimental results, confirming the reliability of the numerical model. The analysis showed that an interference fit in the range of 0.10–0.15 mm generated favorable compressive stress fields in the punch and die, thereby reducing tensile stress concentrations and enhancing tool strength and service life. The findings provide a practical basis for optimizing interference-fit design in cold heading tools used for aluminum alloy rivet manufacturing and contribute to improving tool durability and production efficiency in industrial forming processes.