Chapter 2 – Gas Metal Arc Welding: Modeling

This chapter describes the literature on modeling i.e., the Gas Metal Arc Welding (GMAW) process. The various aspects of the physics of welding are discussed. The aspects of both modeling and power supplies are presented. The modeling of a welding process in general means the derivation of a set of mathematical equations—ordinary differential equations for lumped parameter systems, partial differential equations for distributed parameter systems—describing the physical process by means of fundamental principles of science or statistical and/or experimental techniques. GMAW is a welding process where heat is generated by an electric arc incorporating a continuous-feed consumable electrode that is shielded by an externally supplied gas. In practice, the most common technique to control the welding process variables is to obtain a model based on some empirical data. For example, one can conduct a number of experiments to determine the effect of a certain input variable, and then mathematical expressions can be found to fit the experimental data. The chapter concludes with the presentation of a specific model developed at a U.S. Department of Energy national laboratory, the Idaho National Engineering and Environmental Laboratory (INEEL).