Reverse aging and deformability of steel wire rod: a study by Caleotto and PoliMi

The ability of steel wire rod to undergo deformation without fracturing is a key property in the production of high-performance mechanical components such as cables, bolts, springs, and fasteners. Optimizing this characteristic means achieving higher process efficiency, fewer rejects, and improved downstream workability.

A recent study by Caleotto S.p.A., in collaboration with the Department of Mechanical Engineering of Politecnico di Milano, delves into this crucial aspect by analyzing the influence of hot rolling and cooling parameters on the deformability of wire rods for mechanical applications. The research, presented at the Wire & Cable Kraków 2025 conference, also investigates the intriguing metallurgical phenomenon known as reverse aging — the natural recovery of ductility observed in steel wire rods after a period of storage.

Extending the study beyond high-carbon steels

Although reverse aging is well documented in high-carbon steels, this work demonstrates that the same phenomenon also occurs in medium- and low-carbon steels. The study focused on two different grades, 30MnB4 and C82D2+Cr+V, produced under varying hot rolling and Stelmor cooling conditions. Mechanical tests, metallographic analyses, and hydrogen diffusion studies were carried out to understand how these process parameters affect the kinetics and extent of deformability recovery.

Key findings and industrial implications

The results confirm that precise control of rolling temperature and cooling intensity has a direct impact on the wire rod’s deformability and on the time required to reach its optimal ductility. By adjusting these parameters, it is possible to reduce natural aging times and improve the uniformity of mechanical properties — a significant advantage for both product quality and production planning.

Collaborating with Politecnico di Milano for continuous innovation

The complete article, “Influence of the process parameters on the deformability of wire-rod for mechanical applications”, authored by Riccardo Gerosa, Barbara Rivolta, Mirko Tenca (corresponding author), Lorenzo Angelini, Andrea Parimbelli, Roberto Passoni, Davide Cavenaghi, and Giorgio Motta, was presented at the Wire & Cable Kraków 2025 conference.

This project is part of the long-term collaboration between Caleotto, the Politecnico di Milano, and the Feralpi Group, aimed at fostering innovation through the integration of academic knowledge into industrial practice. The involvement of young researchers from the university brings fresh perspectives and analytical rigor, contributing to Caleotto’s continuous pursuit of excellence and quality improvement in steel production.