Quantitative Ultrasonic Testing and Evaluation of Laser Welds for Stainless Steel Carbody of Rail Transit Vehicles
［Objective］ During the laser welding process of stainless steel carbody of rail transit vehicles, energy transfer from the laser beam to the material is dynamically variable. To ensure the quality of laser welding, non-destructive testing methods are required to evaluate the fusion state of the lase...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | zho |
| Published: |
Urban Mass Transit Magazine Press
2025-02-01
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| Series: | Chengshi guidao jiaotong yanjiu |
| Subjects: | |
| Online Access: | https://umt1998.tongji.edu.cn/journal/paper/doi/10.16037/j.1007-869x.2025.02.012.html |
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| Summary: | ［Objective］ During the laser welding process of stainless steel carbody of rail transit vehicles, energy transfer from the laser beam to the material is dynamically variable. To ensure the quality of laser welding, non-destructive testing methods are required to evaluate the fusion state of the laser welds in stainless steel carbodies. Thus, the laser weld fusion state detection method based on quantitative ultrasonic testing technology is investigated. ［Method］ Materials and preparatory work for the experiments are introduced, and ultrasonic testing experiments are conducted. In the time domain, A-scan signals are extracted and analyzed. In the frequency domain, the FFT (fast Fourier transform) method is used to convert A-scan signals into the time-frequency domain, producing spectral characteristic curves. Using the A-scan signals in the time domain and the spectral characteristic curves in the frequency domain, a calculation model for the fusion width of the laser weld (hereinafter referred to as ′fusion width′) is established. The semi-attenuation method and frequency domain analysis method are used to obtain the simulated values of the fusion width, which are then compared with actual values, followed by the error statistical analysis. ［Result & Conclusion］ The variations in ultrasonic A-scan signals and main frequency amplitude correlate well with the probe position. The fusion widths obtained using the semi-attenuation method and frequency domain analysis method are both valid for assessing weld quality effectively. Compared to the semi-attenuation method, the frequency domain analysis method demonstrates higher accuracy and stability, with the detected error between the simulated fusion width and the actual value within 0.1 mm. This precision meets the requirements for practical engineering applications. |
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| ISSN: | 1007-869X |