Analysis Of Dynamic Physical Property Of TIG Welding Arc In Mixtures Of Argon And Nitrogen Based On Fowler-milne Method

This paper presents a new high-speed acquisition system including twoCCD sensors. The new acquisition system overcomes the limitation ofspectrometer which can only scan by point or progressive and allow thedynamic temperature and concentration field of pulsed argon arc and pulsedargon-nitrogen arc to be derived.Firstly, the temperature filed in a pulsed argon arc had been measured bythe Fowler-Milne method based on high-speed acquisition system includingsingle CMOS. When the change of current happened, intensity andtemperature of arc jumped as well. The farther the distance from tungsten is,the larger the intensity of the arc becomes, and the lower the temperature ofarc has.Secondly, the modified Fowler-Milne method was analyzed for thecalculation of argon-nitrogen arc. The welding arc with the mixtures of80%Ar and20%N2was measured in this paper based on high-speed acquisition system including two CCD sensors. The measured radialdependence of argon mole fraction indicates occurrence of demixing, whichthe argon mole fraction increase as the radius increases.Lastly, the pulsed TIG welding arc with the mixtures of80%Ar and20%N2was analyzed based on high-speed acquisition system including twoCCD sensors. The dynamic temperature and concentration of various axialpositions (1mm,2mm,3mm and4mm) of argon-nitrogen arc were calculated.In the peak period and the base period, the four axial positions have variousdegree of demixing. And the further from tungsten tip, the more the argonmole fraction is. When the change of current happened, the temperature andthe argon mole fraction jumped as well. And the further from tungsten, thegreater the argon mole fraction jump.