Recommendations for Improved Welding Procedures for Thick Steel Plates Through Thermo-Mechanical Analysis

Welding of steel plates is accompanied by residual stresses that increase as the constraint provided by the welded components becomes greater. Consequently, crack initiation has been reported after welding thick plates due to the high residual stresses developed by the welding procedure. This is further exacerbated by the higher likelihood of imperfections present in thick steel plates due to the rolling and cooling process. The research described herein aims to develop improved submerged arc welding (SAW) procedures to reduce the residual stresses for steel plates of thickness > 50 mm. Acceptance criteria are developed for discontinuities present in the steel plates prior to welding, to limit the probability of crack initiation. A parametric study of SAW procedure parameters was conducted utilizing a validated finite element model. Two welding procedures were recommended for thick steel plates. Discontinuity acceptance limits were also recommended for each welding procedure using a fracture toughness database and an expression developed to calculate the probability of a crack to initiate.