Theoretical and empirical assessment of evaluation methods of the electric charge transference in welding with covered electrodes

Abstract

The present work is based on an assessment of experimentally obtained results from the application of different methods of evaluation, reported in the specialised literature, of the electrical charge transference stability in the arc. A simple factorial design, taking the welding current as independent variable, was applied to the process with an AWS A5.1 E6013 electrode. The welds were carried out in the flat position by a gravity device. It was possible to obtain criteria to classify the electrical charge transference stability of the process by digital signal processing and a statistical technique. The outcome was based on visual inspection and morphologic studies. It was concluded that amongst the considered parameters, the average value of the arc conductivity during reignition peaks and the quantity of reignition peaks are the more representative indices, both from statistics and from phenomenological points of view. This finding is validated by the fact that the bead morphology and the stability analysis of the electrical charge transference process coincides with the fact that the 160 A (for 4 mm-diameter electrodes) is the most stable regime.

Keywords:

• Welding
• digital processing
• statistics

Acknowledgements

I would like to sincerely thank those who, in one way or another, have collaborated to carry out this paper, and others without whom this would not have been able to be completed to a satisfactory standard, or would not even have been able to be started. I emphasise especially the selfless collaboration of the technicians Jorge V Miguel Oria and Alexis Delgado Gómez in the tasks of metallographic processing of the samples and their assistance at the respective experimental facility, as well as for the high level of professionalism and reliability they demonstrated throughout the course of the present investigation. I would also like to thank colleagues Drs Rafael Quintana Puchol and Carlos René Gómez Pérez for their advice in the initial moments of the paper. I would also like to thank the researchers who preceded me in this topic with such valuable contributions: Drs Vladimir Ponomarev and JP Farias, the editorial board of the most important magazine in Latin American specialising in welding (Soldagem e Inspeção) and in general to all the scientific community related to the field of welding both in Cuba and internationally.