Evolution of Precipitated Phases during Creep of G115/Sanicro25 Dissimilar Steel Welded Joints
This paper studies the evolution of the microstructure and microhardness in the G115 side of the G115/Sanicro25 dissimilar steel welded joint during the creep process. The joints were subjected to creep tests at 675 °C, 140 MPa, 120 MPa and 100 MPa. A scanning electron microscope equipped with an el...
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MDPI AG
2021-09-01
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| Online Access: | https://www.mdpi.com/1996-1944/14/17/5018 |
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| author | Maohong Yang Zheng Zhang Linping Li |
| author_facet | Maohong Yang Zheng Zhang Linping Li |
| author_sort | Maohong Yang |
| collection | DOAJ |
| description | This paper studies the evolution of the microstructure and microhardness in the G115 side of the G115/Sanicro25 dissimilar steel welded joint during the creep process. The joints were subjected to creep tests at 675 °C, 140 MPa, 120 MPa and 100 MPa. A scanning electron microscope equipped with an electron backscattering diffraction camera was used to observe the microstructure of the cross-section. The fracture position of the joint and the relationship between the cavity and the second phase were analyzed. The microstructure morphology of the fracture, the base metal and the thread end was compared and the composition and size of the Laves phase were statistically analyzed. The results show that the fracture locations are all located in the fine-grain heat-affected zone (FGHAZ) zone, and the microstructure near the fracture is tempered martensite. There are two kinds of cavity in the fracture section. Small cavities sprout adjacent to the Laves phase; while large cavities occupy the entire prior austenite grain, there are more precipitated phases around the cavities. The Laves phase nucleates at the boundary of the M<sub>23</sub>C<sub>6</sub> carbide and gradually grows up by merging the M<sub>23</sub>C<sub>6</sub> carbide. Creep accelerates the coarsening rate of the Laves phase; aging increases the content of W element in the Laves phase. |
| first_indexed | 2024-03-10T08:07:33Z |
| format | Article |
| id | doaj.art-1dc6aadd3a214bafb96a2aa279e01da4 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-10T08:07:33Z |
| publishDate | 2021-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-1dc6aadd3a214bafb96a2aa279e01da42023-11-22T10:55:04ZengMDPI AGMaterials1996-19442021-09-011417501810.3390/ma14175018Evolution of Precipitated Phases during Creep of G115/Sanicro25 Dissimilar Steel Welded JointsMaohong Yang0Zheng Zhang1Linping Li2School of Material Science and Engineering, Beihang University, 37 Xueyuan Road, Beijing 100191, ChinaSchool of Material Science and Engineering, Beihang University, 37 Xueyuan Road, Beijing 100191, ChinaShenhua Guohua (Beijing) Electric Power Research Institute Co., Ltd., No.75 Jian Guo Road, Chaoyang District, Beijing 100025, ChinaThis paper studies the evolution of the microstructure and microhardness in the G115 side of the G115/Sanicro25 dissimilar steel welded joint during the creep process. The joints were subjected to creep tests at 675 °C, 140 MPa, 120 MPa and 100 MPa. A scanning electron microscope equipped with an electron backscattering diffraction camera was used to observe the microstructure of the cross-section. The fracture position of the joint and the relationship between the cavity and the second phase were analyzed. The microstructure morphology of the fracture, the base metal and the thread end was compared and the composition and size of the Laves phase were statistically analyzed. The results show that the fracture locations are all located in the fine-grain heat-affected zone (FGHAZ) zone, and the microstructure near the fracture is tempered martensite. There are two kinds of cavity in the fracture section. Small cavities sprout adjacent to the Laves phase; while large cavities occupy the entire prior austenite grain, there are more precipitated phases around the cavities. The Laves phase nucleates at the boundary of the M<sub>23</sub>C<sub>6</sub> carbide and gradually grows up by merging the M<sub>23</sub>C<sub>6</sub> carbide. Creep accelerates the coarsening rate of the Laves phase; aging increases the content of W element in the Laves phase.https://www.mdpi.com/1996-1944/14/17/5018dissimilar steel welded jointcreeplaves phasecavity |
| spellingShingle | Maohong Yang Zheng Zhang Linping Li Evolution of Precipitated Phases during Creep of G115/Sanicro25 Dissimilar Steel Welded Joints Materials dissimilar steel welded joint creep laves phase cavity |
| title | Evolution of Precipitated Phases during Creep of G115/Sanicro25 Dissimilar Steel Welded Joints |
| title_full | Evolution of Precipitated Phases during Creep of G115/Sanicro25 Dissimilar Steel Welded Joints |
| title_fullStr | Evolution of Precipitated Phases during Creep of G115/Sanicro25 Dissimilar Steel Welded Joints |
| title_full_unstemmed | Evolution of Precipitated Phases during Creep of G115/Sanicro25 Dissimilar Steel Welded Joints |
| title_short | Evolution of Precipitated Phases during Creep of G115/Sanicro25 Dissimilar Steel Welded Joints |
| title_sort | evolution of precipitated phases during creep of g115 sanicro25 dissimilar steel welded joints |
| topic | dissimilar steel welded joint creep laves phase cavity |
| url | https://www.mdpi.com/1996-1944/14/17/5018 |
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