Avaliação das técnicas de soldagem no processo MIG/MAG com arame-eletrodo ultrafino de 0,6 mm

Abstract

Usually, ultra-thin wires of Ø 0.6 mm are used for MIG/MAG welding thin plates (up to 1 mm). The metal transfer mode used is of a short-circuit type, although the spray transfer mode in the MIG/MAG welding process is known to provide better bead finish, less spatter and greater penetration compared to short-circuit welding. Previous works have shown that the use of the spray metal transfer mode has caused some difficulty with respect to bead formation due to lack of wetting of the joint edges by the liquid metal from the welding pool. This work verified the possibility of MIG/MAG welding with ultra-thin wire of Ø 0.6 mm and spray transfer using the "pushing" torch displacement technique, with the objective of comparing the quality of the welding bead and to verify if the difficulties of this process observed in previous works were caused by the "pulling" technique used in them. For the experimental procedure, two butt joint specimens with varying clearances were used. In each specimen two weld seams were welded in a way that for one the welder used the "pulling" technique and for the other the "pushing" technique. Even though changing the torch displacement technique from "pulling" to "pushing" promoted better finishing of the weld bead, the other difficulties in performing MIG/MAG welding with 0.6 mm ultra-thin wire electrode, reported in previous works, were not solved and were present during the experimental tests.