Influence of the Longitudinal Magnetic Field on the Formation of the Bead in Narrow Gap Gas Tungsten Arc Welding
Abstract
:1. Introduction
2. Mathematical Model
2.1. Computational Domain
2.2. Governing Equations
2.3. Treatment of Interface
2.4. External Boundary Conditions and Material Properties
3. Results and Discussion
3.1. Welding Arc Behavior under LMF
3.2. Molten Pool Behavior under LMF
3.3. Validation of the Model
4. Conclusions
- (1)
- A unified 3D simulation model for LMF-NG-GTAW is developed including the electrode, welding arc, weld pool, and work piece; it can simulate the arc behavior and the weld pool formation process.
- (2)
- The profile of the deflecting welding arc has a big effect on the heat flux distribution. When the magnetic-field strength is 6 mT, the axis of the arc column moves from the bottom to the side wall; the decrease of the maximum heat flux at the bottom is about one-half, and the maximum heat flux at the side wall is increased by a factor of 10. The heat flux is dispersed along the narrow groove face, and this is helpful to form a uniform penetration weld.
- (3)
- The flow pattern in the weld pool is different with different magnetic-field strength. When the magnetic field is suitable, the flow pattern can transfer heat from the bottom to the side wall.
- (4)
- The model is validated by experimental data from references. Both the percentage deviations of the simulation weld penetration at the side wall and at the bottom from the experimental results are lower than 10%.
Author Contributions
Funding
Conflicts of Interest
References
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Boundary | T (K) | V (m/s) | Φ (V) | A |
---|---|---|---|---|
Gas inlet | 500 | vx = vy = 0, vz = vg | ||
Electrode tip | 3000 | - | ||
Electrode surface | 1000 | - | ||
Gas outlet | 1000 | - | 0 | |
External surfaces of work piece | - | ϕ = 0 |
Nomenclature | Value |
---|---|
freezing point | 1670 K |
melting point | 1727 K |
density | 7200 kg·m−3 |
electric conductivity | 7.7 × 105 S/m |
surface tension coefficient | 1.2 N·m−1 |
surface tension temperature gradient | 1 × 10−4 N·m−1·K−1 |
work function | 4.65 eV |
Magnetic Field Strength (mT) | Weld Pool Width (mm) | Weld Pool Depth (mm) |
---|---|---|
B = 0 | 10.9 | 3.9 |
B = 3 | 12.1 | 2.6 |
B = 9 | 12.8 | 2.3 |
Experimental [13] | Simulation | Deviation | |
---|---|---|---|
Weld width (mm) | 14.6 | 14.2 | 2.8% |
Weld depth (mm) | 2 | 1.8 | 8.7% |
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Jian, X.; Wu, H. Influence of the Longitudinal Magnetic Field on the Formation of the Bead in Narrow Gap Gas Tungsten Arc Welding. Metals 2020, 10, 1351. https://doi.org/10.3390/met10101351
Jian X, Wu H. Influence of the Longitudinal Magnetic Field on the Formation of the Bead in Narrow Gap Gas Tungsten Arc Welding. Metals. 2020; 10(10):1351. https://doi.org/10.3390/met10101351
Chicago/Turabian StyleJian, Xiaoxia, and Hebao Wu. 2020. "Influence of the Longitudinal Magnetic Field on the Formation of the Bead in Narrow Gap Gas Tungsten Arc Welding" Metals 10, no. 10: 1351. https://doi.org/10.3390/met10101351