Horizontal rotating arc narrow-gap GTAW of thick Ti–6Al–4V alloy
The horizontal welding method helps simplify assembly and construction for large cylindrical components. Nonetheless, a notable challenge arises during horizontal welding, as the molten pool tends to flow downward due to gravity. To overcome this problem, a novel horizontal rotating-arc narrow-gap G...
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| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-05-01
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| Series: | Journal of Materials Research and Technology |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785425006118 |
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| Summary: | The horizontal welding method helps simplify assembly and construction for large cylindrical components. Nonetheless, a notable challenge arises during horizontal welding, as the molten pool tends to flow downward due to gravity. To overcome this problem, a novel horizontal rotating-arc narrow-gap GTAW method has been implemented. The rotating arc promotes the flow of the molten metal and counteracts part of the gravity acting on the molten pool when the arc force is applied below it. This suppresses the sagging trend of the molten pool and improves weld formation, ultimately resulting in well-formed and defect-free welded joints. This innovative technique successfully welded horizontally 50 mm thick Ti–6Al–4V alloy plates. During the welding process of the dual-phase titanium alloy, the high-temperature β phase develops in the weld zone (WZ). Columnar crystals are retained with the cooling of the weld and grow epitaxially under the continuous heating and remelting of the subsequent weld. Within the columnar crystals, α′ martensite interlaces with the residual β phase and forms a basketweave structure. The proportion of low-angle grain boundaries and the average Kernel Average Misorientation values of the weld zone are lower than those of the base metal. Benefiting from the martensitic strengthening effect, the tensile strength of the WZ increased by 16.9 % compared to the base metal. The tensile properties exhibit good consistency across the full thickness of the joints. The impact toughness of the WZ is significantly improved, especially showing excellent low-temperature impact toughness at 0 °C. |
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| ISSN: | 2238-7854 |