Investigation of Weld Root Defects in High-Power Full-Penetration Laser Welding of High-Strength Steel
| Autor: | Hengquan Zhang, Meng Jiang, Xi Chen, Lianfeng Wei, Shizhong Wang, Yumo Jiang, Nan Jiang, Zhiyuan Wang, Zhenglong Lei, Yanbin Chen |
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| Rok vydání: | 2021 |
| Předmět: |
root defects
Technology Microscopy QC120-168.85 single pass QH201-278.5 laser welding high power full penetration welding parameters Engineering (General). Civil engineering (General) TK1-9971 Descriptive and experimental mechanics General Materials Science Electrical engineering. Electronics. Nuclear engineering TA1-2040 |
| Zdroj: | Materials, Vol 15, Iss 1095, p 1095 (2022) Materials; Volume 15; Issue 3; Pages: 1095 |
| ISSN: | 1996-1944 |
| Popis: | The currently available high-power laser shows promising opportunities for the welding of thick plates in a single pass. However, weld-root defect frequently occurs when a high-power laser is used to join thick plates in a full-penetration mode, which has a significantly adverse effect on the serviceability of the weld joint. The purpose of this work is to understand the defect formation mechanism and reduce these defects through controlling welding parameters. In this study, the characteristics of weld root defects were investigated using a 10 kW fiber laser using a program of experiment and theoretical analysis. The corresponding defect formation mechanisms were discussed based on the bottom molten pool behaviors observed by the high-speed camera. The results showed that there were four types of weld-root appearances as follows with an increase of linear heat input from 300 J/mm to 1000 J/mm: weld-root humping (30 mm/s), sound weld (25 mm/s), weld sagging (20 mm/s) and excessive weld sagging. The remedies for reducing weld-root defects were also presented to obtain sound weld bead by optimizing welding parameters. Weld-root humping was formed due to the quasi-full-penetration keyhole. Weld sagging resulted from the imbalance of the hydrostatic pressure and surface tension in the condition of a through keyhole. It was also found that the sound weld was formed when a through keyhole and a proper molten pool size were obtained. Thus, the state of the keyhole and molten pool geometry were the major factors that affect weld-root defects. |
| Databáze: | OpenAIRE |
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