Tensile Deformation Analysis of Bead Weld Based on Simple Three Zone Model

Abstract

From a simple model of the bead weld constructed by three zones (base metal (BM) without heat affected zone, heat affected zone (HAZ) and weld metal (WM)), the approximate analysis for the tensile deformation of bead welds (mild steel (arc): three.zones, and copper (TIG and electron beam) and aluminum (TIG): two zones of BM and WM) have been carried out. And the confirmation for the propriety of this analysis is made by the tensile test of their bead welds.As the results, it is found that absolute values of both ratios (σ/σx) and (e/ex) are larger than 0.85 (σ and e: equivalent stress and strain, and σx and ex: normal stress and longitudinal strain), and that the tensile deformation of bead weld is approximately expressed by the tensile deformation of the heterogeneity distribution. Moreover, it is found that initial yield for mild steel, copper (TIG) and aluminum occurs in BM in the vicinity of WM, and yield for copper (electron beam) occurs near the ditch (made by the weld), and that the yielding progresses along the boundary of HAZ (for arc and TIG). Also, it is recognized that the inclination (not perpendicular in the tensile direction) of boundary of HAZ and the contignity between HAZ and WM are necessary for the occurrence of the initial yield and for the yield progress and that the variations of the stress and the strain near boundaries between their zones occurs remarkably.