Modified Mathematical Models for Melting Rate in Submerged Arc Welding

Modified mathematical models for melting rate during submerged arc welding with straight and reverse polarities have been proposed. The present work is a result of a critical analysis of existing models and subsequent modification in order to improve the predictability and practicability. The proposed models bridge the gap between less scientific shop-fioor-friendly models and scientifically correct but not so shop-floor- friendly models. Instead of experimental measurement of electrode extension or making the assumption that the electrode extension is equal to contact tube to work-piece distance, the present work models the role of electrode extension during melting by considering the effect of process parameters on it. On the other hand, influence of process parameters on arc heating has also been incorporated. The developed models cover the effect of fundamental parameters like current, voltage, electrode extension and wire diameters.

Simulated annealing has been used to calibrate the proposed models and subsequently the models are validated with data points different from the points used for model calibration. The modified models provide better accuracy than the models that have been constituted with the above stated assumption as well as it is more practical than those models in which actual electrode extension has been experimentally measured. The outcome of investigation has been analyzed in terms of improvement in the predictability, resemblance with physics of the process and generalization capacity of the models. The approach of the present work is applicable for future research in other welding processes.