VARIABLE-POLARITY THREE-WIRE GAS-SHIELDED INDIRECT ARC WELDING METHOD AND DEVICE, AND USE THEREOF

摘要

A variable-polarity three-wire gas-shielded indirect arc welding method. A welding process is performed by means of three welding wires and two variable-polarity power sources; before welding, a main wire (3) is connected to one pole of each of the two variable-polarity power sources (1, 2), and the remaining two side wires (4, 5) are connected to the other pole of each of the two variable-polarity power sources, respectively; and a welding workpiece (6) is not connected to the two variable-polarity power sources. During welding, the two variable-polarity power sources are started at the same time, the two variable-polarity power sources work synchronously, and the polarities of the variable-polarity power sources connected to the main wire are always the same. By means of periodic positive and negative polarity transformation of the polarities of the variable-polarity power sources, the distribution of a magnetic field surrounding the welding wires is periodically regulated, thereby realizing a welding process of periodic swinging during coupling of indirect arcs. Said method regulates arc deflection, realizes the accurate distribution of energy of a welding arc heat source, and solves the problems of generation of a burn-through defect during high-speed welding of a thin plate and non-melting of a side wall and arc striking of the side wall during narrow gap welding of a thick plate. The present invention also relates to a variable-polarity three-wire gas-shielded indirect arc welding device and use of variable-polarity three-wire gas-shielded indirect arc welding.