Fundamental Study on Weld Formation Phenomena of High Speed Lap Seam Welding (2nd Report)

Effects of Electrode Shape and Plate Thickness on Welding Phenomena

Abstract

The influences of shape and dimensions of electrodes on the weldable current range and effects of plate thickness on welding phenomena are studied. The results obtained are as follows.
Weldable current range ΔI_a/I_av increases with increased ratio of electrode face width W as against the plate thickness t and with increased P/W. The proper face width and electrode force for various thicknesses can be dicided by the equation W/t=6 and P/W=130kg/mm. Improvement of ΔI_a/I_av can be achieved by R type electrodes especially in case of thicker plate thickness as well as efficient electrode force. ΔI/_aI_av is affected little by the outer diameter of electrode over a range from 280 to 400 mm in diameter. ΔI_a/I_av for given welding speed decreases as plate thickness increasees except for welding speed in which the upper limit of welding current is restricted by electrode sticking. The type of weld formation process of other plate thickness can also divided into two types with welding speed. The transition welding speed becomes lower for thicker plate and the melting efficiency is saturated or becomes the maximum value at the transition welding speed.