The effect of exposed length of wire, current intensity and the rate of resurfacing on the process of arc overlaying with self-shielded wire

Abstract

A common characteristic by all of the padding processes in which filler metals are provided by flux cored shielded (GMA), self-shielded (SSA) wires or hidden arc, is the possibility of improving the overlaying efficiency not only by increasing the intensity of the current, but also by keeping it constant together with the rate of welding while extending the intensity of the current, but also by keeping it constant together with the rate of welding while extending the exposed length of wire. A length of the wire extended outside the power terminal by more than usual – depending on diameter – 25 to 40 mm, is, prior to being melted by the arc’s heat, resistance-heated to between 1000 and 1500 °C. This high wire preheating temperature distinctly increases its melting rate (overlaying efficiency) while also reducing the contribution of the base metal to the material of the overlay.