Study on microstructure characteristics and hole expansion mechanism of Ti–Nb–V microalloyed 900 MPa hot-rolled ferrite-bainite high hole expansion steel
In this study, a 900 MPa grade hot-rolled ferrite/bainite high hole expansion steel was developed using thermomechanical controlled processing (TMCP) and medium-temperature coiling with a Ti–Nb–V multi-microalloy design. The effects of cooling rates and coiling temperatures on the microstructure, me...
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Elsevier
2024-11-01
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| Series: | Journal of Materials Research and Technology |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785424025845 |
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| author | Zhengtuan Li Lei Liu Qihe Xue Chunjing Wu Fenghui Lu Zhengzhi Zhao |
| author_facet | Zhengtuan Li Lei Liu Qihe Xue Chunjing Wu Fenghui Lu Zhengzhi Zhao |
| author_sort | Zhengtuan Li |
| collection | DOAJ |
| description | In this study, a 900 MPa grade hot-rolled ferrite/bainite high hole expansion steel was developed using thermomechanical controlled processing (TMCP) and medium-temperature coiling with a Ti–Nb–V multi-microalloy design. The effects of cooling rates and coiling temperatures on the microstructure, mechanical properties, and hole expansion behavior were systematically investigated. The steel, coiled at 600 °C and cooled at a controlled rate (10–25 °C/s), demonstrated an excellent balance of strength and ductility, achieving a tensile strength of 901 MPa and elongation of 23%. The microstructure consisted of approximately 62% ferrite and 38% bainite, characterized by a uniform and fine grain distribution. The high coiling temperature increased the content of Ti–Nb–V composite precipitates, while reduced cooling times promoted the formation of smaller precipitates primarily along dislocation lines and grain boundaries. A hole expansion ratio of 77% was achieved due to the optimized grain morphology and phase ratio, with refined grains and high-angle grain boundaries impeding crack propagation. Additionally, the increased presence of secondary precipitates strengthened the soft phase ferrite and enhanced the coordinated deformation between ferrite and bainite. These combined effects significantly improved the steel's resistance to crack propagation during hole expansion, making it a promising material for applications requiring high strength and formability. |
| format | Article |
| id | doaj-art-4e07c7cd5d2340e1a1abeba899529223 |
| institution | OA Journals |
| issn | 2238-7854 |
| language | English |
| publishDate | 2024-11-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Materials Research and Technology |
| spelling | doaj-art-4e07c7cd5d2340e1a1abeba8995292232025-08-20T02:35:30ZengElsevierJournal of Materials Research and Technology2238-78542024-11-01337469748110.1016/j.jmrt.2024.11.056Study on microstructure characteristics and hole expansion mechanism of Ti–Nb–V microalloyed 900 MPa hot-rolled ferrite-bainite high hole expansion steelZhengtuan Li0Lei Liu1Qihe Xue2Chunjing Wu3Fenghui Lu4Zhengzhi Zhao5School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, China; HBIS Chengde Iron and Steel Group Co., Ltd., Chengde, 067000, ChinaCollaborative Innovation Center of Steel Technology, University of Science and Technology Beijing, Beijing, 100083, China; Corresponding author.HBIS Chengde Iron and Steel Group Co., Ltd., Chengde, 067000, ChinaSchool of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, ChinaHBIS Chengde Iron and Steel Group Co., Ltd., Chengde, 067000, ChinaCollaborative Innovation Center of Steel Technology, University of Science and Technology Beijing, Beijing, 100083, China; Corresponding author.In this study, a 900 MPa grade hot-rolled ferrite/bainite high hole expansion steel was developed using thermomechanical controlled processing (TMCP) and medium-temperature coiling with a Ti–Nb–V multi-microalloy design. The effects of cooling rates and coiling temperatures on the microstructure, mechanical properties, and hole expansion behavior were systematically investigated. The steel, coiled at 600 °C and cooled at a controlled rate (10–25 °C/s), demonstrated an excellent balance of strength and ductility, achieving a tensile strength of 901 MPa and elongation of 23%. The microstructure consisted of approximately 62% ferrite and 38% bainite, characterized by a uniform and fine grain distribution. The high coiling temperature increased the content of Ti–Nb–V composite precipitates, while reduced cooling times promoted the formation of smaller precipitates primarily along dislocation lines and grain boundaries. A hole expansion ratio of 77% was achieved due to the optimized grain morphology and phase ratio, with refined grains and high-angle grain boundaries impeding crack propagation. Additionally, the increased presence of secondary precipitates strengthened the soft phase ferrite and enhanced the coordinated deformation between ferrite and bainite. These combined effects significantly improved the steel's resistance to crack propagation during hole expansion, making it a promising material for applications requiring high strength and formability.http://www.sciencedirect.com/science/article/pii/S2238785424025845Hot-rolled ferrite-bainite steelMicroalloyMicrostructureMechanical propertiesHole expansion mechanism |
| spellingShingle | Zhengtuan Li Lei Liu Qihe Xue Chunjing Wu Fenghui Lu Zhengzhi Zhao Study on microstructure characteristics and hole expansion mechanism of Ti–Nb–V microalloyed 900 MPa hot-rolled ferrite-bainite high hole expansion steel Journal of Materials Research and Technology Hot-rolled ferrite-bainite steel Microalloy Microstructure Mechanical properties Hole expansion mechanism |
| title | Study on microstructure characteristics and hole expansion mechanism of Ti–Nb–V microalloyed 900 MPa hot-rolled ferrite-bainite high hole expansion steel |
| title_full | Study on microstructure characteristics and hole expansion mechanism of Ti–Nb–V microalloyed 900 MPa hot-rolled ferrite-bainite high hole expansion steel |
| title_fullStr | Study on microstructure characteristics and hole expansion mechanism of Ti–Nb–V microalloyed 900 MPa hot-rolled ferrite-bainite high hole expansion steel |
| title_full_unstemmed | Study on microstructure characteristics and hole expansion mechanism of Ti–Nb–V microalloyed 900 MPa hot-rolled ferrite-bainite high hole expansion steel |
| title_short | Study on microstructure characteristics and hole expansion mechanism of Ti–Nb–V microalloyed 900 MPa hot-rolled ferrite-bainite high hole expansion steel |
| title_sort | study on microstructure characteristics and hole expansion mechanism of ti nb v microalloyed 900 mpa hot rolled ferrite bainite high hole expansion steel |
| topic | Hot-rolled ferrite-bainite steel Microalloy Microstructure Mechanical properties Hole expansion mechanism |
| url | http://www.sciencedirect.com/science/article/pii/S2238785424025845 |
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