Research On Energy Distribution Of Point In Three Dimension By Micro-Plasma Arc With Pulsed Current

In essence, the research on welding arc is the research on acoustic signal, electrical signal and optical signal. The complicated physical process is included in combustion process. It is of signality to welding stability, welding thermal cycle, welding formation and welding quality by exploring physical process during arc burning. The intensity of micro-plasma arc was studied as the research object to explore physical process in welding arc.The pictures were taken by high-speed photography technology with different parameters of pulse. The grey value of the arc pictures were extracted by Matlab. The rules of light intensity distribution through arc central axis was analyzed which became the principle of how to choose the characteristic cross section. The spectra collection system was used to collect the data of each characteristic cross section. And information of several cycle is contained by one point that was collected from spectra collection system. For the pulsed current, because of the current was constantly changed with the pulse cycle from base value to peak value. And the characteristic cross section can not be confirmed. So, both the characteristic cross section pulse base value and peak value would be got which would be the object of collection. And all the optional cross section would the object of collection. After that, the rule of light intensity in characteristic cross section would be compared.The accuracy of collection data of arc light intensity can be the presupposition of calculating the point in three-dimension of arc. Although, all the data was be collected by spectra collection system, the obvious error was made by the defect of light path system. In that way, the collection data would be decoupled by Abel inversion. After relative emission coefficient was gotten by Abel inversion, relative intensity method was used to calculate the inside temperature of micro-plasma welding arc.All the calculation and analysis in the paper is based on the local thermodynamic equilibrium. So the analysis about if the micro-plasma welding arc stays at state of the local thermodynamic equilibrium is studied in the paper. The pulse cycle was divided into two processes. One is steady state, the other is dynamic state. During the steady state, if the electrical density arrived at the value of critical, the arc would be indicated that stays at state of the local thermodynamic equilibrium. During the dynamic state, the percentage of steady state among all the cycle was calculated and decided if the error was under the control.During the process of welding, arc would be supported by electromagnetic force, buoyancy, surface tension and arc force which function together. Under any circumstance, the force inside arc can’t be neglect. The main purpose in this part is to do a research about distribution of electromagnetic force inside of micro-plasma are welding arc in some different pulsed welding parameters. In fact, the arc electromagnetic force is perpendicular to inside electric streamline. And point to the inside of welding arc. Because of the electric streamline is not perpendicular to the workpiece. The arc electromagnetic force is not the force which is perpendicular to the central axis of arc. In this chapter, the electromagnetic force was divided into two parts. One is radial electromagnetic force, the other is axial electromagnetic force. Both of these two kind electromagnetic force would be discussed in this article.