Evolution of ultrafine bainite microstructure during rapid heating process and the role of retained austenite
Rapid heat treatment is an important method to improve the properties of steel. Moreover, the study of the phase transformation process plays an important role in the formulation of rapid heat treatment. This paper investigates phase transformation behavior and microstructure evolution of ultrafine...
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| Format: | Article |
| Language: | English |
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Elsevier
2023-11-01
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| Series: | Journal of Materials Research and Technology |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785423029277 |
| _version_ | 1827346084652908544 |
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| author | Changbo Liu Qiwen Fang Jianjun Wang Hongguang Li Xubiao Wang Dongyun Sun Zhinan Yang Fucheng Zhang |
| author_facet | Changbo Liu Qiwen Fang Jianjun Wang Hongguang Li Xubiao Wang Dongyun Sun Zhinan Yang Fucheng Zhang |
| author_sort | Changbo Liu |
| collection | DOAJ |
| description | Rapid heat treatment is an important method to improve the properties of steel. Moreover, the study of the phase transformation process plays an important role in the formulation of rapid heat treatment. This paper investigates phase transformation behavior and microstructure evolution of ultrafine bainite at varying heating rates, and reveals the influence mechanism of retained austenite on austenitizing. Results showed that the decomposition of retained austenite was influenced by the diffusion of Si element. Therefore, the decomposition temperature of retained austenite is severely affected by the heating rate. Retained austenite completely transformed into cementite and ferrite when heating rate was below 5 °C/s. A small amount of retained austenite was kept when the heating rate was higher than 5 °C/s. The kept austenite effectively suppressed the hysteresis of Ac1 and resulted in a unique mechanism of austenite grain formation. When the heating rate range was 5–10 °C/s, some new austenite skipped the nucleation process and grew directly on the kept austenite, forming the large austenite grains. And other new austenite was obtained via nucleation and growth process. Thus, the grain size of bimodal distribution is formed. This leads to the phenomenon of austenite memory effect. When the heating rate was increased to 50 °C/s and higher, the austenite grain size was less than 14 μm. Therefore, rapid heating makes the phase transition lag. When the heating rate is high enough, part of the austenite is kept, which has an important influence on austenitizing process of the steel. |
| first_indexed | 2024-03-07T23:23:04Z |
| format | Article |
| id | doaj.art-9abd31ee90f84a90881a10484453b0b4 |
| institution | Directory Open Access Journal |
| issn | 2238-7854 |
| language | English |
| last_indexed | 2024-03-07T23:23:04Z |
| publishDate | 2023-11-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Materials Research and Technology |
| spelling | doaj.art-9abd31ee90f84a90881a10484453b0b42024-02-21T05:28:09ZengElsevierJournal of Materials Research and Technology2238-78542023-11-012769246935Evolution of ultrafine bainite microstructure during rapid heating process and the role of retained austeniteChangbo Liu0Qiwen Fang1Jianjun Wang2Hongguang Li3Xubiao Wang4Dongyun Sun5Zhinan Yang6Fucheng Zhang7State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066004, ChinaState Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066004, ChinaNational Engineering Research Center for Equipment and Technology of Cold Strip Rolling, Yanshan University, Qinhuangdao, 066004, ChinaNational Engineering Research Center for Equipment and Technology of Cold Strip Rolling, Yanshan University, Qinhuangdao, 066004, ChinaState Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066004, ChinaCollege of Metallurgy and Energy, North China University of Science and Technology, Tangshan, 063210, ChinaState Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066004, China; National Engineering Research Center for Equipment and Technology of Cold Strip Rolling, Yanshan University, Qinhuangdao, 066004, China; Corresponding author. National Engineering Research Center for Equipment and Technology of Cold Strip Rolling, Yanshan University, Qinhuangdao, 066004, China.State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066004, China; College of Metallurgy and Energy, North China University of Science and Technology, Tangshan, 063210, ChinaRapid heat treatment is an important method to improve the properties of steel. Moreover, the study of the phase transformation process plays an important role in the formulation of rapid heat treatment. This paper investigates phase transformation behavior and microstructure evolution of ultrafine bainite at varying heating rates, and reveals the influence mechanism of retained austenite on austenitizing. Results showed that the decomposition of retained austenite was influenced by the diffusion of Si element. Therefore, the decomposition temperature of retained austenite is severely affected by the heating rate. Retained austenite completely transformed into cementite and ferrite when heating rate was below 5 °C/s. A small amount of retained austenite was kept when the heating rate was higher than 5 °C/s. The kept austenite effectively suppressed the hysteresis of Ac1 and resulted in a unique mechanism of austenite grain formation. When the heating rate range was 5–10 °C/s, some new austenite skipped the nucleation process and grew directly on the kept austenite, forming the large austenite grains. And other new austenite was obtained via nucleation and growth process. Thus, the grain size of bimodal distribution is formed. This leads to the phenomenon of austenite memory effect. When the heating rate was increased to 50 °C/s and higher, the austenite grain size was less than 14 μm. Therefore, rapid heating makes the phase transition lag. When the heating rate is high enough, part of the austenite is kept, which has an important influence on austenitizing process of the steel.http://www.sciencedirect.com/science/article/pii/S2238785423029277Ultrafine bainiteRapid heatingPhase transformationAustenite memory effectRetained austenite |
| spellingShingle | Changbo Liu Qiwen Fang Jianjun Wang Hongguang Li Xubiao Wang Dongyun Sun Zhinan Yang Fucheng Zhang Evolution of ultrafine bainite microstructure during rapid heating process and the role of retained austenite Journal of Materials Research and Technology Ultrafine bainite Rapid heating Phase transformation Austenite memory effect Retained austenite |
| title | Evolution of ultrafine bainite microstructure during rapid heating process and the role of retained austenite |
| title_full | Evolution of ultrafine bainite microstructure during rapid heating process and the role of retained austenite |
| title_fullStr | Evolution of ultrafine bainite microstructure during rapid heating process and the role of retained austenite |
| title_full_unstemmed | Evolution of ultrafine bainite microstructure during rapid heating process and the role of retained austenite |
| title_short | Evolution of ultrafine bainite microstructure during rapid heating process and the role of retained austenite |
| title_sort | evolution of ultrafine bainite microstructure during rapid heating process and the role of retained austenite |
| topic | Ultrafine bainite Rapid heating Phase transformation Austenite memory effect Retained austenite |
| url | http://www.sciencedirect.com/science/article/pii/S2238785423029277 |
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