Study On The Correlation Between GMAW Electrical Signal And The Stability Of Welding Process

The electric signal of welding current and arc voltage in GMAW could reflect the stability of welding process. The characteristic parameters of electrical signal can conveniently and intuitively describe the stability of welding process. Effective extraction of the characteristic parameters related to welding process stability from electrical signal is the key to describe the stability of welding process. In this paper, the author researched on the correlation between the stability of welding process and welding electrical signals through collecting and analyzing welding electrical signals, extracting its characteristic parameters, measuring welding splashing rate and combing them with droplet transfer in high-speed camera, which provides a scientific method to evaluate GMAW process performance quantitatively, assess welding wire quality.The welding technology experiment of copper wire, no copper plating welding wire and flux cored wire in different technological conditions was carried out. The author collected the real-time electrical signals by using the current voltage sensor and A/D conversion module. The original electrical signals curve was smoothed by S-G method firstly and then further smoothed by the method of burr angle membership function model. Afer that, the interference signal was effectively eliminated, so that the problem that the characteristic parameters could not be extracted from original electrical signals can be solved. Through the analysis of the electrical signal waveform after smoothing and high-speed camera photos of droplet transfer, the author found that the fluctuation period of the electrical signal is related to the droplet transition period.In this paper, the author designed welding electrical signal data processing algorithm and program by using C++ programming tools and then process and analyze the welding electrical signals from different welding technological conditions, extracting some characteristic parameters such as current average value, standard deviation of current, current amplitude, standard deviation of amplitude, current fluctuations period, the standard deviation of fluctuations period. The results show that the characteristic parameters is closely related to the stability of welding process, smaller the characteristic parameters such as current average value, standard deviation of current, current amplitude, standard deviation of amplitude, current fluctuations period, the standard deviation of fluctuations period was, the more stable the welding process was and lower the splashing rate was. Through the model, the welding splashing rate can be predicted by analyzing welding electrical signal and also the stability of the welding process can be evaluated.In this paper, the effect of active agent in the gas welding of molten gas was studied, finding that the active agent can improve the stability of the welding process and increase the penetration depth. In this experiment, the active agent which ratio of TiO2 and SiO2 is 3:7 shows the best effect to reduce welding splashing rate. The use of active agents makes the characteristic parameters such as current average value, standard deviation of current, current amplitude, standard deviation of amplitude, current fluctuations period and the standard deviation of fluctuations period turn smaller, improve the stability of the welding process and effectively reduce the welding splashing rate. The experimental data of the active agent verify the reliability of the model which shows the relationship between the welding signal characteristic parameters and the welding splash rate.