Original Article

Influence of alloying elements and strain rate on the second ductility minimum of microalloyed steels during simulated continuous casting

¹ K1-MET GmbH, Stahlstrasse 14, 4020 Linz, Austria
² Institute of Materials Science, Joining and Forming at the Graz University of Technology, Kopernikusgasse 24/I, 8010 Graz, Austria
³ Voestalpine Stahl GmbH, voestalpine-Strasse 1, 4020 Linz, Austria

^* e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 19 August 2025
Accepted: 3 January 2026

Abstract

The ductility behavior of continuously cast steel is a key factor influencing strand quality and crack susceptibility. Therefore, investigating the parameters that affect ductility is of great importance for enhancing the productivity of the method by producing defect-free products. This study investigates the differences in ductility behavior between two microalloyed steels with different C, Mn, Al, Ti, B, and S content subjected to hot tensile testing at strain rates of 10⁻² s⁻¹ and 10⁻³ s⁻¹ at 750 °C, 800 °C, and 850 °C. The first material is low-carbon microalloyed steel with a higher amount of Mn, Al, and S, and the second contains higher C, Ti, and B. Both steels were tested after in-situ melting using an induction heating system in a vacuum chamber, followed by a hot tensile test until fracture. An initial microstructural analysis was conducted to study the influence of chemical composition, temperature, and strain rate on both steels. Furthermore, the precipitation kinetics of both steels were evaluated using MatCalc software, which provided predictions for the expected precipitates. The results indicate that the steel with higher C, Ti, and B, and lower Mn and S content exhibits better ductility at both strain rates. This was attributed to the influence of alloying elements on the formation of precipitates and the kinetics of austenite-ferrite transformation, in addition to fewer MnS particles. These effects are associated with the preferential formation of coarse TiN rather than AlN and BN.