Study on oscillation modes of weld pool in stationary GTA welding using structure laser method

Abstract

To study the oscillation mode of GTA weld pool, the oscillation mode of weld pool was analyzed based on Bessel equation, and the laser dot matrix images of (0, 1), (1, 1), (2, 1), (0, 2) oscillation modes at different times are obtained by structured laser optical measurement simulation. The oscillation mode of stationary GTA weld pool was analyzed based on the laser dot matrix images obtained by structure laser experiment. The result shows the simulated laser dot matrix images matches up to the experiment result. The oscillation mode of the weld pool can be recognized based on laser dot matrix image. This study can not only provide conditions for judging the penetrating state of weld pool, but also help to further understand the oscillation mode of the weld pool and develop more effective observation methods and measurement tools, so as to effectively control and improve the welding quality.

Study on the Oscillating Phenomenon of Welding Pool with Different Penetration States in Short-Circuiting GMAW

“…The calculated oscillation frequency is compared with the actual measured oscillation frequency of the weld pool, as shown in Figure 10. It can be found from Figure 10 that the actual oscillation frequency of the weld pool with different penetration states under different wire feeding speeds is close to the calculated result of Equation (7).…”

“…Although the oscillation amplitude of the full penetration weld pool is twice that of the partial penetration state, both the synchronous voltage signals were similar, as shown in Figure 11b,c. It can be found from Figure 10 that the actual oscillation frequency of the weld pool with different penetration states under different wire feeding speeds is close to the calculated result of Equation (7).…”

“…Reference [6] shows that the oscillation phenomenon of the weld pool in GTAW has stable frequency characteristics, and the weld pool has two oscillation modes: one is the axisymmetric vibration of the geometric center of the weld, and the other is asymmetric vibration. Reference [7] found that the change of the weld pool penetration state could cause a sudden change in the oscillation mode, and the natural oscillation frequency of the weld pool has a direct physical relationship with the weld pool volume.…”