Evaluation of welding process stability and weld formation during laser-MIG hybrid welding

In underwater wet welding, the unstable welding process caused by the generation and rupture of bubbles and the chilling effect of water on the welding area result in low quality of welded joints, which makes it difficult to meet the practical application of marine engineering. To improve the process stability and joining quality, a mixture of welding flux with a water glass or epoxy resin was placed on the welding zone before underwater welding. In this paper, welds’ appearance, geometry statistics of welds’ formation, welding process stability, slag structure, microstructure, pores and mechanical properties were investigated. It was found that with the addition of water glass in the mixture, the penetration of weld was effectively increased, and the frequency of arc extinction was reduced. Though the porosity rose to a relatively high level, the joints’ comprehensive mechanical properties were not significantly improved. Notably, the applied epoxy resin completely isolated the surrounding water from the welding area, which greatly improved process stability. Furthermore, it benefited from the microstructure filled with massive acicular ferrite, the average elongation and room temperature impact toughness increased by 178.4%, and 69.1% compared with underwater wet welding, respectively, and the bending angle of the joint reaches to 180°.

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Observation of Arc Behaviour in TIG/MIG Hybrid Welding Process

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/596/1/012025 ◽

2020 ◽

Vol 596 ◽

pp. 012025

Author(s):

Rose Alifah Ellyana Roslan ◽

Sarizam Mamat ◽

Pao Ter Teo ◽

Firdaus Mohamad ◽

Srinath Gudur ◽

...

Keyword(s):

Welding Process ◽

Hybrid Welding

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Effects of Wire Rotating Frequency on Metal Transfer Process in Rotating Arc Narrow Gap Horizontal GMAW

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.189-193.3395 ◽

2011 ◽

Vol 189-193 ◽

pp. 3395-3399 ◽

Cited By ~ 7

Author(s):

Ning Guo ◽

Yan Fei Han ◽

Chuan Bao Jia ◽

Yong Peng Du

Keyword(s):

Transfer Process ◽

High Speed ◽

Stable Process ◽

Welding Process ◽

Metal Transfer ◽

Welding Parameters ◽

High Speed Photography ◽

Narrow Gap ◽

Weld Formation ◽

Rotating Arc

The metal transfer process with different welding parameters in rotating arc narrow gap horizontal welding is successfully observed by the high-speed photography system. The effects of wire rotating frequency on metal transfer process in rotating arc narrow gap horizontal welding are novelly explored. The metal transfer with different wire rotating frequency presents different modes. The results indicate that the droplet transfer has stable process with the rotating frequency of 5-20 Hz. And the weld formation is quite shapely. But with the high rotating frequency of 50 Hz, the metal transfer process is not acceptable and the weld formation is very pool. Metal transfer process is one of the most important factors of effecting the weld formation in rotating arc horizontal welding process besides the molten pool behavior and welding thermal circles.

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Correlation between wire feed speed and external mechanical constraint for enhanced process stability in underwater wet flux-cored arc welding

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1177/0954405418811783 ◽

2018 ◽

Vol 233 (10) ◽

pp. 2061-2073 ◽

Cited By ~ 2

Author(s):

Jianfeng Wang ◽

Qingjie Sun ◽

Jiangkun Ma ◽

Peng Jin ◽

Tianzhu Sun ◽

...

Keyword(s):

Welding Process ◽

Electrical Signal ◽

Feed Speed ◽

Process Stability ◽

Underwater Wet Welding ◽

Extinction Process ◽

Flux Cored Arc Welding ◽

Wire Feed Speed ◽

Wire Feed ◽

Mechanical Constraint

It is a great challenge to improve the process stability in conventional underwater wet welding due to the formation of unstable bubble. In this study, mechanical constraint method was employed to interfere the bubble generated by underwater wet welding, and the new method was named as mechanical constraint assisted underwater wet welding. The aim of the study was to quantify the combined effect of wire feed speed and condition of mechanical constraint on the process stability in mechanical constraint assisted underwater wet welding. Experimental results demonstrated that the introduction of mechanical constraint not only suppressed the bubble without floating but also stabilized the arc burning process. The degree of influence of mechanical constraint, which changed with wire feed speed, played an important role during the mechanical constraint assisted underwater wet welding process. For all wire feed speeds, the fluctuations of welding electrical signal were decreased through introduction of mechanical constraint. The difference in the proportion of arc extinction process between underwater wet welding and mechanical constraint assisted underwater wet welding became less with increasing wire feed speed. At wire feed speed lower than 7.5 m/min, the improvement of process stability was very significant by mechanical constraint. However, the further improvement produced limited effect when the wire feed speed was greater than 7.5 m/min. The observation results showed that a better weld appearance was afforded at a large wire feed speed, corresponding to a lower variation coefficient.

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