Microstructure evolution and creep behavior of nitrogen-bearing austenitic Fe–Cr–Ni heat-resistant alloys with various carbon contents
In the petrochemical industry, centrifugal cast Fe–Cr–Ni heat-resistant alloy tubes are critical components that are exposed to severe conditions for long-time service. The life of the alloy tubes is primarily limited by creep damages, which can evolve into catastrophic failures. In order to improve...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2023-03-01
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| Series: | Journal of Materials Research and Technology |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785423000182 |
| _version_ | 1797858813914644480 |
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| author | Shulin Xiang Zhichao Fan Tao Chen Xiaoming Lian Yihui Guo |
| author_facet | Shulin Xiang Zhichao Fan Tao Chen Xiaoming Lian Yihui Guo |
| author_sort | Shulin Xiang |
| collection | DOAJ |
| description | In the petrochemical industry, centrifugal cast Fe–Cr–Ni heat-resistant alloy tubes are critical components that are exposed to severe conditions for long-time service. The life of the alloy tubes is primarily limited by creep damages, which can evolve into catastrophic failures. In order to improve the creep properties in a low-cost approach, the influence of N + C content on the microstructure evolution and creep behavior of the 25Cr35NiNb alloys has been studied in this work. Creep tests were carried out at 1173 K (900 °C) and 1323 K (1050 °C) with different stress levels. Microstructure investigation on precipitates revealed that the C/N ratio significantly affects the content and morphology of Cr-rich carbides and the phase transition of Nb-rich carbonitrides after thermal exposure. By adopting the threshold stress analysis, the true creep activation energy and stress exponent of all the alloys were found to be ∼270 kJ mol−1 and ∼5, respectively, which indicated that dislocation climb is the rate-controlling mechanism of creep. Furthermore, the tailored novel N-bearing alloy possessed superior comprehensive properties of creep resistance and damage tolerance compared to the 25Cr35NiNb grade alloys. Our current findings not only realize improved creep properties by the combined modification of N addition and C/N ratio, but also provide new insights into understanding the microalloying mechanisms of high-temperature materials in general. |
| first_indexed | 2024-04-09T21:19:25Z |
| format | Article |
| id | doaj.art-5a9a28bfa11041f8854d420a23de2ee5 |
| institution | Directory Open Access Journal |
| issn | 2238-7854 |
| language | English |
| last_indexed | 2024-04-09T21:19:25Z |
| publishDate | 2023-03-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Materials Research and Technology |
| spelling | doaj.art-5a9a28bfa11041f8854d420a23de2ee52023-03-28T06:45:47ZengElsevierJournal of Materials Research and Technology2238-78542023-03-0123316330Microstructure evolution and creep behavior of nitrogen-bearing austenitic Fe–Cr–Ni heat-resistant alloys with various carbon contentsShulin Xiang0Zhichao Fan1Tao Chen2Xiaoming Lian3Yihui Guo4National Engineering Technical Research Center on Pressure Vessels and Piping Safety, Hefei General Machinery Research Institute Co., Ltd., Hefei 230031, China; Special Equipment Inspection Station Co., Ltd. of Hefei General Machinery Research Institute, Hefei 230031, China; Corresponding author. National Engineering Technical Research Center on Pressure Vessels and Piping Safety, Hefei General Machinery Research Institute Co., Ltd., Hefei 230031, China.National Engineering Technical Research Center on Pressure Vessels and Piping Safety, Hefei General Machinery Research Institute Co., Ltd., Hefei 230031, China; Special Equipment Inspection Station Co., Ltd. of Hefei General Machinery Research Institute, Hefei 230031, ChinaNational Engineering Technical Research Center on Pressure Vessels and Piping Safety, Hefei General Machinery Research Institute Co., Ltd., Hefei 230031, China; Special Equipment Inspection Station Co., Ltd. of Hefei General Machinery Research Institute, Hefei 230031, ChinaNational Engineering Technical Research Center on Pressure Vessels and Piping Safety, Hefei General Machinery Research Institute Co., Ltd., Hefei 230031, China; Special Equipment Inspection Station Co., Ltd. of Hefei General Machinery Research Institute, Hefei 230031, ChinaCollege of Materials, and Fujian Key Laboratory of Surface and Interface Engineering for High Performance Materials, Xiamen University, Xiamen 361005, ChinaIn the petrochemical industry, centrifugal cast Fe–Cr–Ni heat-resistant alloy tubes are critical components that are exposed to severe conditions for long-time service. The life of the alloy tubes is primarily limited by creep damages, which can evolve into catastrophic failures. In order to improve the creep properties in a low-cost approach, the influence of N + C content on the microstructure evolution and creep behavior of the 25Cr35NiNb alloys has been studied in this work. Creep tests were carried out at 1173 K (900 °C) and 1323 K (1050 °C) with different stress levels. Microstructure investigation on precipitates revealed that the C/N ratio significantly affects the content and morphology of Cr-rich carbides and the phase transition of Nb-rich carbonitrides after thermal exposure. By adopting the threshold stress analysis, the true creep activation energy and stress exponent of all the alloys were found to be ∼270 kJ mol−1 and ∼5, respectively, which indicated that dislocation climb is the rate-controlling mechanism of creep. Furthermore, the tailored novel N-bearing alloy possessed superior comprehensive properties of creep resistance and damage tolerance compared to the 25Cr35NiNb grade alloys. Our current findings not only realize improved creep properties by the combined modification of N addition and C/N ratio, but also provide new insights into understanding the microalloying mechanisms of high-temperature materials in general.http://www.sciencedirect.com/science/article/pii/S2238785423000182Heat-resistant alloys25Cr35NiNbCreepMicrostructurePrecipitates |
| spellingShingle | Shulin Xiang Zhichao Fan Tao Chen Xiaoming Lian Yihui Guo Microstructure evolution and creep behavior of nitrogen-bearing austenitic Fe–Cr–Ni heat-resistant alloys with various carbon contents Journal of Materials Research and Technology Heat-resistant alloys 25Cr35NiNb Creep Microstructure Precipitates |
| title | Microstructure evolution and creep behavior of nitrogen-bearing austenitic Fe–Cr–Ni heat-resistant alloys with various carbon contents |
| title_full | Microstructure evolution and creep behavior of nitrogen-bearing austenitic Fe–Cr–Ni heat-resistant alloys with various carbon contents |
| title_fullStr | Microstructure evolution and creep behavior of nitrogen-bearing austenitic Fe–Cr–Ni heat-resistant alloys with various carbon contents |
| title_full_unstemmed | Microstructure evolution and creep behavior of nitrogen-bearing austenitic Fe–Cr–Ni heat-resistant alloys with various carbon contents |
| title_short | Microstructure evolution and creep behavior of nitrogen-bearing austenitic Fe–Cr–Ni heat-resistant alloys with various carbon contents |
| title_sort | microstructure evolution and creep behavior of nitrogen bearing austenitic fe cr ni heat resistant alloys with various carbon contents |
| topic | Heat-resistant alloys 25Cr35NiNb Creep Microstructure Precipitates |
| url | http://www.sciencedirect.com/science/article/pii/S2238785423000182 |
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