Abstract: A non-transferred plasma arc system, which is provided with a non-transferred plasma torch (1) that is provided with a non-consumable electrode (101) as a negative electrode and an insert chip as a positive electrode, the insert chip being cooled by a circulated coolant (W) and the insert chip releasing a plasma arc onto a workpiece. The plasma arc torch (1) comprises a TIG welding torch (100) that is provided with the non-consumable electrode (101), whereby an arc is generated between the workpiece and said electrode (101), and a torch nozzle (105), which releases a shield gas toward an arc-generated weld pool of the workpiece. The plasma arc torch (1) is provided with an attachment (51) that is detachably attached to the TIG welding torch (100) while surrounding the periphery of the torch nozzle (105) and that functions as the insert chip, whereby a non-transferred plasma arc is inexpensively and easily used.

Abstract: A hybrid welding method capable of improving arc stability and improving the welding speed and the welding efficiency is provided. A hybrid welding method includes generating a TIG arc on a leading side in a welding direction and generating a MIG arc on a trailing side in the welding direction to weld a base metal, in which a TIG current is set to be higher than a MIG current so as to continuously generate arcs in a TIG electrode and a MIG electrode, and an absolute value of a distance from an intersection between a central axis of the TIG electrode and a surface of the base metal to an intersection between a central axis of the MIG electrode and the surface of the base metal is 20 mm or less.

Abstract: A non-transferred plasma arc system, which is provided with a non-transferred plasma torch (1) that is provided with a non-consumable electrode (101) as a negative electrode and an insert chip as a positive electrode, the insert chip being cooled by a circulated coolant (W) and the insert chip releasing a plasma arc onto a workpiece. The plasma arc torch (1) comprises a TIG welding torch (100) that is provided with the non-consumable electrode (101), whereby an arc is generated between the workpiece and said electrode (101), and a torch nozzle (105), which releases a shield gas toward an arc-generated weld pool of the workpiece. The plasma arc torch (1) is provided with an attachment (51) that is detachably attached to the TIG welding torch (100) while surrounding the periphery of the torch nozzle (105) and that functions as the insert chip, whereby a non-transferred plasma arc is inexpensively and easily used.

Abstract: Provided is a plasma arc welding method for continuously welding a welding target part of a welding workpiece while forming a keyhole weld on the welding target part of the welding workpiece using a plasma arc. A pulse current is used for a welding current, and the pulse frequency of the pulse current is controlled so as to be a frequency that is synchronized with a weld pool (P) during the welding. With this approach, vibration of the weld pool during keyhole welding can be controlled so as to synchronize with the pulse frequency of the pulse current. As a result, when the plasma arc keyhole welding is performed, a stable penetration bead having a desired height can be reliably obtained without hanging or irregularity.

Abstract: A hybrid welding method capable of improving arc stability and improving the welding speed and the welding efficiency is provided. A hybrid welding method includes generating a TIG arc on a leading side in a welding direction and generating a MIG arc on a trailing side in the welding direction to weld a base metal, in which a TIG current is set to be higher than a MIG current so as to continuously generate arcs in a TIG electrode and a MIG electrode, and an absolute value of a distance from an intersection between a central axis of the TIG electrode and a surface of the base metal to an intersection between a central axis of the MIG electrode and the surface of the base metal is 20 mm or less.

Abstract: Provided is a plasma arc welding method for continuously welding a welding target part of a welding workpiece while forming a keyhole weld on the welding target part of the welding workpiece using a plasma arc. A pulse current is used for a welding current, and the pulse frequency of the pulse current is controlled so as to be a frequency that is synchronized with a weld pool (P) during the welding. With this approach, vibration of the weld pool during keyhole welding can be controlled so as to synchronize with the pulse frequency of the pulse current. As a result, when the plasma arc keyhole welding is performed, a stable penetration bead having a desired height can be reliably obtained without hanging or irregularity.

Abstract: The method of monitoring keyhole welding with a plasma arc includes the step of measuring output voltages when welding is performed with a constant current, and the step of finding peak frequencies and distributions of welding voltages by analyzing frequencies of the welding voltages which correlate to a molten weld pool (P) vibration among the output voltages measured. The method also includes the step of identifying the peak frequencies that correlate to the molten weld pool (P) vibration, and the step of comparing the identified peak frequencies with a frequency range and determining whether the welding is good or bad. Thus, whether or not good keyhole welding is carried out can be determined with excellent precision by simply comparing the peak frequency that correlates to the molten weld pool (P) vibration with the frequency range.

Abstract: An object of the present invention is to provide a hybrid welding method which can improve the stability of the arc, the welding speed, and welding efficiency, and the present invention provides a hybrid welding method in which a TIG arc is generated on the front side in the welding direction, and a MIG arc is generated on the back side in the welding direction in order to weld a welding base material, wherein electric current for the TIG welding is larger than electric current for the MIG welding; and an absolute value of the interval between an intersection of a center axis of a TIG electrode and a surface of the welding base material and an intersection of a center axis of a MIG electrode and the surface of the welding base material is 4 mm or less.