Initiation Behavior of Microscopic Short Cracks in Weld Toe of Structural Steel Q345B
Aiming at the base metal (BM) zone, heat affected zone (HAZ) and fusion zone (FZ) of the weld, the tip plastic zone and initiation behavior of microscopic short cracks (MSCs) in the toe of cross-welded joints are studied. Based on the theory of crack tip plastic zone and the fatigue index parameter...
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MDPI AG
2022-04-01
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| Series: | Metals |
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| Online Access: | https://www.mdpi.com/2075-4701/12/4/618 |
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| author | Lifu Cheng Xinyuan Chen Guoqian Wei Fan Ye |
| author_facet | Lifu Cheng Xinyuan Chen Guoqian Wei Fan Ye |
| author_sort | Lifu Cheng |
| collection | DOAJ |
| description | Aiming at the base metal (BM) zone, heat affected zone (HAZ) and fusion zone (FZ) of the weld, the tip plastic zone and initiation behavior of microscopic short cracks (MSCs) in the toe of cross-welded joints are studied. Based on the theory of crack tip plastic zone and the fatigue index parameter (FIP), the shape and boundary size of the plastic zone at the tip of MSCs as well as the initiation life were calculated. The results show that the plastic zone was bone-like under plane stress and butterfly-like under plane stress; when the crack length increased from 2 μm to 30 μm, the boundary size of the plastic zone at the MSC tip increased by 15 μm and 2 μm under the action of plane stress and plane strain in the X-axis direction, respectively. As the grain gradient decreased from 0.5 to 0.1, the boundary size of the plastic zone at the tip of the MSC increased about 50%. MSC initiation occurs first in the BM zone, and life of initiation was about several hundred thousand cycles, which was consistent with the experimental result. The MSC expansion rate in BM zone was the fastest, with the average expansion rate about 2.5 × 10<sup>−3</sup> μm/cycle; the MSC expansion rate in the FZ and HAZ was about 3.1 × 10<sup>−4</sup> μm/cycle. |
| first_indexed | 2024-03-09T04:25:24Z |
| format | Article |
| id | doaj.art-f3c7c48b2b1e4b60a773770b8417d24e |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-09T04:25:24Z |
| publishDate | 2022-04-01 |
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| series | Metals |
| spelling | doaj.art-f3c7c48b2b1e4b60a773770b8417d24e2023-12-03T13:42:29ZengMDPI AGMetals2075-47012022-04-0112461810.3390/met12040618Initiation Behavior of Microscopic Short Cracks in Weld Toe of Structural Steel Q345BLifu Cheng0Xinyuan Chen1Guoqian Wei2Fan Ye3Key Laboratory of Metallurgical Equipment and Control Technology, Wuhan University of Science and Technology, Ministry of Education, Wuhan 430081, ChinaKey Laboratory of Metallurgical Equipment and Control Technology, Wuhan University of Science and Technology, Ministry of Education, Wuhan 430081, ChinaKey Laboratory of Metallurgical Equipment and Control Technology, Wuhan University of Science and Technology, Ministry of Education, Wuhan 430081, ChinaKey Laboratory of Metallurgical Equipment and Control Technology, Wuhan University of Science and Technology, Ministry of Education, Wuhan 430081, ChinaAiming at the base metal (BM) zone, heat affected zone (HAZ) and fusion zone (FZ) of the weld, the tip plastic zone and initiation behavior of microscopic short cracks (MSCs) in the toe of cross-welded joints are studied. Based on the theory of crack tip plastic zone and the fatigue index parameter (FIP), the shape and boundary size of the plastic zone at the tip of MSCs as well as the initiation life were calculated. The results show that the plastic zone was bone-like under plane stress and butterfly-like under plane stress; when the crack length increased from 2 μm to 30 μm, the boundary size of the plastic zone at the MSC tip increased by 15 μm and 2 μm under the action of plane stress and plane strain in the X-axis direction, respectively. As the grain gradient decreased from 0.5 to 0.1, the boundary size of the plastic zone at the tip of the MSC increased about 50%. MSC initiation occurs first in the BM zone, and life of initiation was about several hundred thousand cycles, which was consistent with the experimental result. The MSC expansion rate in BM zone was the fastest, with the average expansion rate about 2.5 × 10<sup>−3</sup> μm/cycle; the MSC expansion rate in the FZ and HAZ was about 3.1 × 10<sup>−4</sup> μm/cycle.https://www.mdpi.com/2075-4701/12/4/618microscopic short crackcrack tip plastic zoneweld toeinitiation lifegrain mode |
| spellingShingle | Lifu Cheng Xinyuan Chen Guoqian Wei Fan Ye Initiation Behavior of Microscopic Short Cracks in Weld Toe of Structural Steel Q345B Metals microscopic short crack crack tip plastic zone weld toe initiation life grain mode |
| title | Initiation Behavior of Microscopic Short Cracks in Weld Toe of Structural Steel Q345B |
| title_full | Initiation Behavior of Microscopic Short Cracks in Weld Toe of Structural Steel Q345B |
| title_fullStr | Initiation Behavior of Microscopic Short Cracks in Weld Toe of Structural Steel Q345B |
| title_full_unstemmed | Initiation Behavior of Microscopic Short Cracks in Weld Toe of Structural Steel Q345B |
| title_short | Initiation Behavior of Microscopic Short Cracks in Weld Toe of Structural Steel Q345B |
| title_sort | initiation behavior of microscopic short cracks in weld toe of structural steel q345b |
| topic | microscopic short crack crack tip plastic zone weld toe initiation life grain mode |
| url | https://www.mdpi.com/2075-4701/12/4/618 |
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