Comparative study on SAW welding induced distortion and residual stresses of CSEF steel considering solid state phase transformation and preheating

In the present study, experimental and 3-D Finite element analysis of single pass single sided square butt submerged arc welding of 10 mm thick Creep Strength Enhanced Ferritic (CSEF) steel plate was carried out to investigate the residual stresses and deformations with and without the effect of preheating. In Finite Element (FE) model, the bead geometry was considered similar to weld joint for more accuracy. The solid-state phase transformation or austenitic-martensitic transformation characteristic of CSEF steel was also considered in modelling. Thermal history, distortion and residual stresses were predicted for as welded and preheated weld models and validated with experimentally measured results. Deep hole drilling techniques was carried out for residual stress measurement. The residual deformation was measured on coordinate measuring machine. It was observed that preheating effectively reduced the edge deflection and angular deformation values by 41.7 % and 54.1 % respectively. Preheating exhibited a favourable effect on longitudinal residual stress distribution by reducing the values by the maximum difference of 90 %. It was found that FE modelling with solid state phase transformation effect effectively predicted the residual stresses and deformation results with an error of 16.67 % & 26.57 % (maximum) and 3.15 % & 4.35 % (minimum) respectively.