Influence of Microalloying Elements and Deformation Parameters on the Recrystallization and Precipitation Behavior of Two Low-Alloyed Steels

Stefan Monschein, Marlene Kapp, Dominik Zügner, Josef Fasching, Andreas Landefeld, Ronald Schnitzer

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    Abstract

    The alloy design of modern high-strength low-alloy (HSLA) steels aims for a well-balanced combination of high toughness and strength. Using niobium and titanium as microalloying elements together with thermomechanical processing is a common way to obtain a fine-grained microstructure and therefore enhance the strength and toughness of HSLA steels. Herein, a low-alloyed steel and a microalloyed HSLA steel are investigated in the as-rolled condition and by double-hit experiments using various deformation parameters. Atom probe tomography, scanning transmission electron microscopy inside a scanning electron microscope, transmission kikuchi diffraction, and energy-dispersive X-ray spectroscopy are used to investigate the precipitates in the as-rolled condition and after deformation. It is shown that Nb-enriched TiN precipitates with an average size of around 15 nm are responsible for grain refinement in the as-rolled condition. The annealing temperature prior to the rolling process is set below the solution temperature of Nb(C,N). Enhancing the annealing temperature in the double-hit deformation tests above the solution temperature of Nb(C,N) leads to the precipitation of fine NbC precipitates with a size of around 5 nm. These precipitates are responsible for inhibited static recrystallization behavior.

    Original languageEnglish
    Article number2100065
    Number of pages9
    JournalSteel research international
    Volume92.2021
    Issue number9
    Early online date24 Mar 2021
    DOIs
    Publication statusPublished - Sept 2021

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    © 2021 The Authors. Steel Research International published by Wiley-VCH GmbH

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