A model has been developed correlating the anode temperature profile with the dynamic melting rate in gas metal arc welding. Components of this model are identified as the electrode melting rate, temperature-dependent resistivity of electrode and arc voltage. The differential equations describing the dynamic behavior of the electrode extension were derived from mass continuity and energy relations. The temperature of the electrode extension was determined by convective heat transfer and joule heating. One-dimensional solutions of temperature and heat content were used to obtain the dynamic melting rate equation. The purpose of the present paper is to provide quantitative analyses, concentrating on the thermal behavior and the electrical characteristics of the arc welding system, to aid in a fundamental understanding of the process, and to develop a dynamic model that may be used in adaptive control. The model is tested by comparing simulations to experimental results.