Finite Element Modeling of Temperature Cycles in Axi-Symmetric Flash Butt Welded Thin Steel Rods and Experimental Validation

Abstract

Flash butt welding is a process designed to produce a forge-type butt weld between two metal pieces of similar shape. A one-dimensional finite element (FE) modeling of the temperature profile in axi–symmetric flash butt welded steel rods was carried out and results were verified by experimentation. A linear interpolation function was used in the weighted residual expression which was transformed into a matrix temperature values. Non-uniform nodal spacing was used with more concentration of nodes around the heat affected zone (HAZ). Welding process variables examined include; effect of pre-heat temperature, flash temperature, flash duration, and material geometries on temperature profile at various points along the rod. With a typical weld rod diameter of 5 mm and length 40 mm, at weld flash duration of 2 seconds peak temperatures of 572.6, 304.8, 214.2 and 170 0C were attained at distances 1, 2, 3 and 4 mm respectively from weld canter. At a distance 5 mm from weld center the thermal profile computed by finite element model were compared with experimental results obtained using type k thermocouple. Peak temperature values of 134.8 °C and 132 °C obtained for FE modeling and laboratory experiments respectively indicating a good agreement to within 2.1 % between peak temperatures.