Author Affiliations
1Sinopec Jiangsu Petroleum Construction Engineering Co., Ltd., Yangzhou 225009, Jiangsu, China2Shandong Natural Gas Pipeline Co., Ltd., Jinan 250014, Shandong, China3State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001,Heilongjiang, Chinashow less
Fig. 1. Schematic diagram of T-joint with titanium alloy skin grid structure
Fig. 2. Schematic diagram of T-joint laser welding process
Fig. 3. Main weld morphology characteristics of T-joint and characteristic quantity of welds under different test conditions. (a) Main morphology characteristics of welds; (b) P=2000 W, V=1.0 m/min; (c) P=2200 W, V=1.0 m/min; (d) P=2200 W, V=0.8 m/min
Fig. 4. Schematic diagram of measurement of geometric characteristic quantity of molten pool and keyhole
Fig. 5. Molten pool morphologies under different welding process parameters. (a) P=1000 W, V=1.0 m/min; (b) P=2000 W, V=1.0 m/min; (c) P=2000 W, V=2.0 m/min; (d) P=3000 W, V=2.0 m/min
Fig. 6. Outline of molten pool and keyhole
Fig. 7. Significance level of characteristic quantity of molten pool to the weld. (a) Significance level of weld penetration; (b) significance level of weld joint width
Fig. 8. Correlation between characteristic quantity of molten pool and welds. (a) Correlation of weld penetration; (b) correlation of weld joint width
Fig. 9. Regression model of weld joint width. (a) Regression model; (b) regression model residuals
Fig. 10. Regression model of weld penetration. (a) Regression model; (b) regression model residuals
Fig. 11. Size errors of weld topography predicted by regression model
Element | C | O | H | N | Al | V | Fe | Mo | Zr | Ti |
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Mass fraction /% | 0.10 | 0.015 | 0.015 | 0.05 | 5.5‒7.0 | 0.8‒2.5 | 0.25 | 0.5‒2.0 | 1.5‒2.5 | Bal. |
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Table 1. Chemical composition of base metal of TA15 titanium alloy
Welding parameter | Parameter value |
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Laser power /kW | 1.0,1.2,1.4,…,2.8,3.0 | Welding speed /(m·min-1) | 0.8,1.0,1,2,…,2.2,2.4 | Protective gas | Ar | Protective gas flow /(L·min-1) | 15 |
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Table 2. Technological parameters of laser welding test for titanium alloy T-joint
No. | Welding parameters | Molten pool feature | Weld feature |
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P /W | V /(m·min-1) | L /mm | W /mm | R /(°) | M /mm | S /mm2 | WP /mm | WW /mm |
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1 | 1000 | 0.8 | 4.15 | 2.50 | 38.21 | 11.02 | 8.82 | 3.04 | 1.72 | 2 | 1000 | 1.0 | 3.86 | 2.21 | 38.31 | 10.23 | 7.02 | 2.72 | 1.30 | 3 | 1000 | 1.2 | 3.79 | 2.02 | 37.81 | 9.73 | 6.33 | 2.53 | 1.02 | 4 | 1200 | 0.8 | 4.68 | 2.70 | 34.71 | 12.27 | 10.14 | 3.20 | 1.81 | 5 | 1200 | 1.0 | 4.59 | 2.25 | 34.61 | 11.44 | 8.38 | 3.01 | 1.37 | 6 | 1200 | 1.2 | 4.38 | 2.11 | 30.71 | 10.50 | 6.72 | 2.79 | 1.16 | 7 | 1400 | 0.8 | 5.18 | 2.64 | 29.31 | 13.06 | 10.38 | 3.68 | 1.96 | 8 | 1400 | 1.0 | 4.91 | 2.53 | 1.01 | 12.31 | 9.21 | 3.29 | 1.61 | 9 | 1400 | 1.2 | 4.72 | 2.29 | 1.01 | 11.53 | 7.82 | 3.09 | 1.36 |
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Table 3. Part of the molten pool morphology characteristic data
a0 | a1 | a2 | a3 | a4 | a5 |
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0.17559 | 1.21041 | -0.52678 | -0.35576 | 0.28463 | -0.36479 |
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Table 4. Regression model coefficients of weld joint width
a0 | a1 | a2 | a3 | a4 | a5 |
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5.64472 | 0.00119 | -3.80834 | 5.28598×10-7 | 0.97741 | -2.27567×10-4 |
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Table 5. Regression model coefficients of weld penetration
Item | DF | SS | MSE | F0 | P | R2 /% |
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Regression | 5 | 19.50248 | 3.90050 | 2647.92561 | 1.446×10-4 | 97.163 | Residual | 82 | 0.12079 | 0.00147 | | | Total | 87 | 19.62327 | | | |
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Table 6. Analysis of regression model of T-joint weld joint width
Item | DF | SS | MSE | F0 | P | R2 /% |
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Regression | 5 | 12.74066 | 2.54813 | 2173.93311 | 1.446×10-4 | 97.973 | Residual | 82 | 0.09611 | 0.00117 | | | Total | 87 | 12.83678 | | | |
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Table 7. Analysis of regression model of T-joint weld penetration