Dynamically-Flexible Arc - A Novel Interpretation for the High Performance GMAW

摘要

A number of versions of the MIG/MAG process has appeared in themarket to cope with the welding of joints formed by high thicknesssheets without the need for beveling. This originated in the 1980s underthe designation of Transferred Ionized Molten Energy (TIME), whereasthe 1990s saw the names Rapid Arc and Rapid Melt emerge and in early2001 the technique was revisited under the name of Buried Arc. Thesedevelopments did not reveal and do not reveal in principle any specialversion of the MIG/MAG, but rather showed technical implementationsand the conjugation of variables and parameters to improve thegeometric profile of the bead obtained, although some submitted patentapplications. Recent modern product launches from 2010 on, in a hugeprofusion of new nomenclatures and many under the aegis thateverything depends on a special technology embedded in the weldingpower sources have overwhelmed the users lately. This paper presentsa new interpretation for what is really critical to achieve a highperformance of the MIG/MAG process in terms of penetration. Thewelding power source may be based on the more conventional mode ofthe process, i.e. in the voltage control mode (CV). However, what thesource effectively has to meet is a certain dynamic response in order tosustain a metastable equilibrium of the molten pool that is deepened inthe joint in the form of a semikeyhole. The equipment must react veryrapidly in the face of a physical contact between the wire-electrode andthe weld pool and return to its steady state very slowly. This type ofpower source reaction is what some manufacturers obtain by the use ofpulsed current, but without any correlation with the control of themetallic transfer, as claimed by these manufacturers. The present workpresents practical results of both welding and the method to determinethe required dynamic behavior of welding sources suitable for thistechnology.