1. Isothermal decomposition of carbon and nitrogen-enriched austenite in 23MnCrMo5 low-alloy steel
- Author
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H.P. Van Landeghem, Moukrane Dehmas, S.D. Catteau, M. Courteaux, Sabine Denis, Julien Teixeira, A. Redjaïmia, J. Dulcy, Institut Jean Lamour (IJL), Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Science et Ingénierie des Matériaux et Procédés (SIMaP ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Labex DAMAS, Université de Lorraine (UL), PSA Peugeot - Citroën (PSA), PSA Peugeot Citroën (PSA), ANR-11-LABX-0008,DAMAS,Design des Alliages Métalliques pour Allègement des Structures(2011), Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), PSA Peugeot Citroën (FRANCE), Université de Lorraine (FRANCE), Centre Interuniversitaire de Recherche et d'Ingénierie des Matériaux - CIRIMAT (Toulouse, France), and Institut National Polytechnique de Toulouse - INPT (FRANCE)
- Subjects
Materials science ,Polymers and Plastics ,Matériaux ,Alloy steel ,Nucleation ,Low-alloy steel ,02 engineering and technology ,Nitride ,engineering.material ,01 natural sciences ,Ferrite (iron) ,0103 physical sciences ,Phase transformations ,Génie des procédés ,Microstructure ,010302 applied physics ,Austenite ,Isothermal austeniteeferrite transformation ,Carbonitriding ,Precipitation (chemistry) ,Metallurgy ,Metals and Alloys ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,Electronic, Optical and Magnetic Materials ,Isothermal transformation diagram ,Ceramics and Composites ,engineering ,0210 nano-technology - Abstract
International audience; The industrial importance of carbonitriding is owed to the exceptional wear and fatigue resistance it imparts to treated steel parts. This resistance is related to microstructural changes occurring during the enrichment treatment and upon cooling. Here, the effects of interstitial contents, in particular nitrogen, and transformation temperature were investigated in 23MnCrMo5 steel. Samples were homogeneously enriched in the austenitic phase and the isothermal transformation of the enriched austenite between 750 °C and 600 °C was studied. CrN was found to precipitate during the enrichment treatment. During subsequent isothermal holding, CrN precipitate as fine platelets in nitrogen containing samples. At equal carbon content, ferrite formed faster and in finer grains in presence of nitrogen. Preexisting CrN facilitate ferrite nucleation resulting in more numerous ferrite grains. The intense nitride precipitation is the main origin for enhanced hardness in nitrogen-enriched alloys. The exact mechanism leading to the observed microstructures could not be determined and remains under investigation. In particular, the high nitrogen supersaturation of ferrite required to produce the observed fraction of CrN has to be explained.
- Published
- 2018
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