Research On Characteristics Of Hyperbaric Pulsed Mag Welding Arc And Droplet Transfer

With the rapid expansion of the offshore oil resources development, undersea oil pipelines and other mechanical structures damaged repair become a increasingly prominent issue. Contrast the domestic and international development status of underwater pipelines repair area, Underwater dry hyperbaric welding has the advantage of safe and reliable become a often used method to repair the undersea oil pipelines, because it ruled out the water’s influence on the welding process. But now, the issues of hyperbaric welding arc stable and droplet transition has not resolved, subsea pipeline welding quality is difficult to meet the requirements.This paper relies on the Power features impact of the hyperbaric welding arc behavior and control strategy Foundation, the hyperbaric pulse MAG welding test system has being designed and optimized. On this basis, conducted a study on the hyperbaric pulse MAG welding arc, It was shown that the arc energy loss intensifies with increasing the environment pressure resulting in less stable welding process.In order to obtain a stable hyperbaric welding process, the pulsed MAG welding current and voltage waveforms in different air environmental pressures were analysed using statistical method. The relationship between probability density distribution of arc voltage and current and the hyperbaric welding arc stability under different ambient pressure were also investigated, and combined with the high-speed camera system to shoot droplet transfer process. It was shown that compensated the loss of arc energy by increase the arc voltage can make the welding process stable.On the basis of the arc voltage compensation, this paper researched the relationship between hyperbaric pulse MAG welding gas mixing ratio and its stability. Gas ratio influenced on the pulse MAG welding spatter rate, droplet transfer and welding penetration shape were analyzed in different environmental pressure. It was shown that choice the right gas mixing ratio can changed the arc shape in high ambient pressure, thus change its droplet transfer mode, thereby increasing the pulse MAG welding arc stability and its welding quality.In order to eliminate or compensate the environmental pressure effects on the welding process, adjusted the welding power and its other welding parameters were used, this paper provided theoretical basis and experimental foundation for the hyperbaric pulse MAG welding to optimize and match the welding parameter. And its provided a solid technical reserves of offshore oil and many other underwater engineering industry, it has great scientific significance and engineering application prospects.