Increasing the arc burning stability during electric arc surfacing using ribbon electrode

Abstract

The issues of stability of the arc during surfacing with a ribbon electrode are considered. It is shown that the electric arc movement along the end of the electrode is not progressive, but chaotic. In this case, the surfacing process is accompanied by periodic short circuits of the ribbon electrode on the workpiece. It was established experimentally that in order to improve the quality of the deposited metal, it is necessary to provide an operating mode with minimal fluctuations of the arc current. To solve this problem, it is necessary to realize the possibility of rapid destruction of the jumper, which is formed when the electrode is shorted on the workpiece, and to ensure reliable re-excitation of the electric arc. Regarding this, it is is proposed a method and a system for improving arc stability during arc surfacing with a ribbon electrode, consisting of an inverter with a microcontroller control, matching high-frequency power transformer, the secondary winding of which is connected through a capacitor in parallel to the welding arc. When a short circuit is detected between electrode and the workpiece (by catching the reduction of the voltage on the arc gap), the generator is turned on at the resonant frequency of the circuit formed by the capacitor and the inductance of the secondary circuit. A high-frequency component with an amplitude of several kA is superimposed on the main operating current, which leads to rapid heating and destruction of the jumper. The destruction is detected by the control system by «seeing» the increase of voltage on the arc gap. After that, the generator is turned off until the next short circuit is detected