ARC IGNITION METHOD FOR REVERSED POLARITY NONCONSUMABLE ELECTRODE TYPE ARC WELDING METHOD

摘要

PURPOSE:To improve the industrial value of the titled are ignition method by putting plasma toward base metal in an electric field generating between a nonconsumable electrode and the base metal and easily igniting an arc and preventing noise damage of a control circuit and a loss of a main electrode without damaging a measuring instrument. CONSTITUTION:The tungsten electrode (main electrode) 2 of a welding torch 7 is connected with the positive pole side of a power source 1 for welding having a DC drooping characteristic and the base metal 3 is connected with its negative pole side and an electric current is applied to its electric current 8 and the electric field is generated between the main electrode 2 and the base metal 3. Moreover, a tungsten electrode (auxiliary electrode) 12 is connected with the negative pole side of a plasma devise 10 and a plasma nozzle 13 is connected with its positive pole side and an electric current is applied to its plasma circuit 18 and the plasma is put into the electric field between the auxiliary electrode 12 and the base metal 3. The positive ions of the plasma are accelerated with the electric field and collides against the base metal 3 and causing a temperature of a collision part to rise and the arc is easily ignited with the voltage of the power source 1 for welding. The damage of the measuring instrument due to the impressed high voltage of a high-frequency ignition method, the malfunctional damage of the control circuit due to the generating noise and the electrode loss in a touch ignition method are prevented and the industrial value is improved.