In arc welding process, the interesting regions for heat transfer analysis are the fusion zone (FZ) and the heat affected zone (HAZ), where high temperatures are reached. These high temperature levels cause phase transformations and alterations in the mechanical properties of the weldedmetal. In the present work, a comparison is made between thermal cycles obtained from analytical models base on the integral method with Gaussian (distributed) heat sources and other results base on the concentrated heat source model. Though the integral method is approximate methods, it have proven to give simple solutions with acceptable accuracy for transient heat transfer. The comparison shows that the thermal cycles obtained from the distributed heat source model are more reliable than those obtained from the concentrated heat source model. Also results show that the use of distributed heat source prevents infinite temperatures values near the fusion zone.