Modelling of angular distortion of double-pass butt-welded plate

Adequate top and bottom side weld reinforcements are important for single-side submerged arc welded butt joints as the shrinkage forces generated due to the solidification of top side weld reinforcements and bottom side weld reinforcements can cancel out each other to minimize angular distortions. In the present investigation it was experimentally established during submerged arc welding (SAW) that by using proper process parameters adequate bottom and required top weld reinforcements could be obtained by using two welding passes for 12 nun thick square butt joints. During the experimental investigation the first pass of welding was used for adequate bottom reinforcement and for filling up the root gap. The second welding pass was used to achieve the required top reinforcement. The first pass weld acted like a restraint to angular distortion induced due to the weld of the second pass. The process was modelled using three-dimensional finite element analysis considering a distributed moving heat source, reinforcements, filler material deposition in each pass of welding, and temperature-dependent material properties.