Experimental Research on Humping Bead of Vertical High-speed GMAW

doi:10.3901/JME.2020.14.073

Abstract

Abstract: The production of humping bead has seriously restricted the application of gas metal arc welding (GMAW) in vertical welding. At present, a little researches on this technological difficulty have been done and no simple effective suppression measures have been put forward. Therefore the formation mechanism of humping bead in the horizontal high-speed GMAW is combed, and base on which experimental research on humping bead of the vertical high-speed GMAW is conducted by the independently developed wall-climbing robot. It is found that the humping bead will occur in the vertical high-speed GMAW when the upward welding is carried out. The main reason for the formation of humping bead is the backward liquid flow generated by arc pressure, droplet impact force and gravity. In addition, the welding current and welding speed significantly influence the morphology of humping bead. When the downward welding is carried out, the direction of the welding and the tilt position of the welding torch is changed, so that the flow direction of the backward liquid flow generated by the arc pressure and the droplet impact force in the molten pool is opposite to the direction of gravity, which can effectively suppresses the formation of the humping bead. To sum up, the gravity of metal liquid flow is used to suppress the formation of hump bead in the vertical high-speed GMAW, which greatly improves the welding speed and welding current and has great application value.

Key words: vertical high-speed GMAW, wall-climbing robot, humping bead, upward welding, downward welding

CLC Number:

TG444

GUO Zhen, ZHANG Li, ZHOU Wei, BI Guijun, HAN Bing. Experimental Research on Humping Bead of Vertical High-speed GMAW[J]. Journal of Mechanical Engineering, 2020, 56(14): 73-80.

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