Design of an induction system for induction assisted alternating current gas metal arc welding

Abstract

Recent work on the low heat input and high deposition rate welding process of pulsed alternating current gas metal arc welding (AC-GMAW) has paved the way for the implementation of a cost effective solution for thick plate welding. Intense plasma jets are achieved through a high current and high electrode negative (EN) ratio based pulsed AC-GMAW, which has high negative peak currents in the EN region of the pulse. A distinct arc behavior results in high arc center temperatures and finger penetration, whereas the weak surrounding arc results in a lack of fusion on the joint sides for material thicknesses above 8mm. The controlled induction pre-heating of the joint sides up to the desired depth can help in overcoming this problem. Numerical simulations of the induction source were performed using temperature-dependent material properties to find the optimal induction heating parameters that will result in the desired penetration depth and temperature. Experiments were conducted on a scaled-down induction system to verify the simulation model. Reasonable results were observed, confirming the proposed methodology. A full-scale induction power system needs to be implemented together with the AC-GMAW process to experimentally verify the application of the induction-assisted alternating current gas metal arc welding (IA-ACGMAW) system to thick plate welding, especially to thermally treated high-strength steels.