The usability of metal-arc welding electrodes, the quality of the welds and the rate at which welds can be made depend in a measure on electrode burn-off rate.Factors which cause these differences in burn-off rates are described.In electric metal-arc welding, a high-current arc is maintained between a metal electrode and the pieces to be welded.The electrode is continuously consumed by fusion of its tip.The melted metal at the tip of the electrode is transferred across the arc gap into the weld as particles of various sizes and possibly also as vaporized metal.Furthermore, a part of the work piece is melted by the heat of the arc as the electrode advances along the weld joint. The character of metal transfer is influenced considerably by the rate at which the tip of the electrode is melted or burns off . In crossing the arc, the molten metal from the electrode tip causes current fluctuations in the welding circuit of which the arc is a part. These fluctuations affect the arc stability and, in manual welding, the ease with which the welder can manipulate the electrode.Thus, the usability of metal-arc welding electrodes, the quality of the welds and the rate at which welds can be made, depend to a certain extent upon the electrode burn-off rate.