Numerical Simulation of Constricted Sheet Tungsten Electrode Arc Characteristic with Insulating Solid Wall in Ultra Narrow Gap Welding Process

doi:10.3901/JME.2020.02.069

Abstract

Abstract: The TIG arc characteristics in ultra narrow gap could be changed by the combined regulation of sheet tungsten electrode and insulating solid wall for avoiding lack of fusion on the corner of square groove. For understanding the regulation mechanism of constricted sheet tungsten electrode arc characteristic with insulating solid wall in ultra narrow gap welding, the three-dimensional quasi-steady state mathematical model of constricted sheet tungsten electrode arc characteristic with insulating solid wall in ultra narrow gap welding process is presented based on a set of partial differential equations and reasonable boundaries conditions. The distributions of temperature, velocity and current density of constricted arc in ultra narrow gap welding process are obtained with different constricted effect of insulating solid wall. The results show that the temperature field, flow field and electric field of constricted sheet tungsten electrode arc with insulating solid wall in ultra narrow gap welding process are symmetric at width direction of ultra narrow gap groove; the insulating solid wall would change the characteristics of constricted arc by cathode and anode control effect; the different constricted height could provide combined regulation of cathode and anode control effect, by which the maximum current density, temperature and plasma velocity of constricted arc enhanced; meanwhile this combined regulation would also restrict the flow of arc current on the side; the variation of constricted width would only bring about cathode control effect to take greater current density, temperature and plasma velocity of constricted arc, and the flow of arc current on the side could not be avoided; when the cathode and anode control effects are stronger, the higher temperature region, current density and cathode jet of constricted arc in ultra narrow gap groove could shift further to the location of sheet tungsten electrode with smaller discharge gap.

Key words: constricted arc, three dimension model, numerical simulation, ultra narrow gap welding

CLC Number:

TG403

LI Yuanbo, YANG Tao, ZHENG Shaoxian, ZHAO Xilong. Numerical Simulation of Constricted Sheet Tungsten Electrode Arc Characteristic with Insulating Solid Wall in Ultra Narrow Gap Welding Process[J]. Journal of Mechanical Engineering, 2020, 56(2): 69-76,85.

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