Electrode-Metal Transfer and Surface Phenomena
Melting and transfer of electrode or filler metal to the part proceed in the processes of fusion welding, and, primarily, arc welding processes, conducted with consumable electrodes or filler materials. The mode of electrode-metal melting and transfer has a considerable influence on many processes, occurring in welding, and this influence is largely dependent on the kind of welding process. In electroslag welding, the process of electrode-metal melting and transfer is connected with the presence of non-metallic inclusions and impurities in the weld metal. In gas welding, it is related to the composition of the deposited metal and its formation. However, the role of electrode-metal melting and transfer is particularly important in arc welding processes. In this case, they are associated with the efficiency of the welding process, arcing stability, formation and chemical homogeneity of the weld metal, electrode-metal losses for burn-out and spatter, metal interaction with the slag and the gases, etc. Therefore, in this chapter we will focus on electrode-metal transfer in arc welding processes and investigation of the role of surface tension forces in this process. This exercise will provide a knowledge of the facts and factors for influencing and controlling the processes more efficiently.