Characteristics of Magnetic Field Assisting Plasma GMAW-P

Abstract

The droplet transfer and voltage-current characteristics of gas metal arc welding (GMAW) in single-pulsed GMAW (single GMAW-P), plasma pulsed GMAW (plasma GMAW-P), and plasma-GMAW-P with a magnetic field were studied using the synchronous acquisition system of high-speed camera and electric signals. The results showed the plasma arc and magnetic field had a significant effect on the droplet transfer process. The indirect arc of the plasma and gas metal arc emerged in the pulse peak phase causing a shunt phenomenon of the GMAW current. The period of the indirect arc was increased under the action of the magnetic field. In hybrid plasma GMAW-P, when the GMAW current did not exceed 140 A, several pulsed one-drop free transfers occurred and the droplet transfer period decreased with the increase in the plasma welding current; when the GMAW current exceeded 140 A, and the plasma welding current was less than 180 A, spray transfer was formed. The droplet transfer transformed into a projected transfer when the plasma welding current increased to 180 A. In plasma-GMAW-P hybrid welding with a magnetic field, the magnetic field had a slight effect on the transfer period. When the GMAW current did not exceed 140 A, the droplet transfer was mainly repelled transfer. The detaching location was on the right side of the wire when the magnetic field current was less than 3 A. When the magnetic field current exceeded 3 A, it was below or on the left side of the wire. When the GMAW current exceeded 140 A and the magnetic field current was less than 5 A, spray transfer was formed, but the droplet transfer mode transformed into a projected transfer with a magnetic field current of 5 A.