Influence of Austempering Temperature on Microstructure and Mechanical Properties of High-Silicon Carbide-Free Bainitic Steel |
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Authors: | Mattia Franceschi Luca Pezzato Claudio Gennari Denise Hanoz Rachele Bertolini Alberto Fabrizi Marina Polyakova Katya Brunelli Franco Bonollo Manuele Dabalà |
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Affiliation: | 1. Department of Industrial Engineering, University of Padova, Via Marzolo 9, 35131 Padova, Italy;2. Department of Industrial Engineering, University of Padova, Via Venezia 9, 35131 Padova, Italy;3. Department of Management and Engineering, University of Padova, Stradella San Nicola 3, 36100 Vicenza, Italy;4. Department of Mechanical Engineering and Metallurgical Technologies, Nosov Magnitogorsk State Technical University, pr. Lenina, 38, 455000 Magnitogorsk, Russia |
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Abstract: | The microstructural evolution of a novel high-silicon carbide-free bainitic steel at different austempering temperatures is investigated. The microstructure is evaluated by means of optical and electron microscopy, X-ray diffraction, microhardness, and nanohardness. Results show a variation in the amount of stabilized retained austenite changing the temperature of the isothermal treatment. In particular, it is observed an increase in the retained austenite volume fraction increasing the temperature up to 350 °C, while further increase leads to a reduction. Moreover, increasing the isothermal holding temperature from 250 °C, through 300, 350, and 370 °C, a progressive bainite coarsening and an increase in the amount of stabilized carbon-enriched retained austenite are observed. Tensile tests reveal an excellent combination of mechanical properties: mechanical strength in the range 1276–1988 MPa and total elongation 0.18–0.44. |
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Keywords: | bainite heat treatments high-strength steels mechanical properties |
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