Letterbox Type Repair Weld Finite Element Simulation and Residual Stress Prediction

Finite element prediction of residual stresses in a 3-bead letterbox-type repair weld is investigated in the present study. The repair is performed on a 2¼CrMo low alloy ferritic steel plate, containing a machined central groove where three weld beads are deposited using AL CROMO S 225 2¼CrMo electrodes. The proposed simulation procedure, which is based on decoupled thermal and mechanical analyses and the “birth and death of elements” technique, is evaluated through comparison of predicted stresses with neutron diffraction testing data. Parametric studies include modelling aspects such as 2-D plane strain versus 3-D analysis, re-melting of weld material during sequential bead deposition, melting of base plate near the fusion line and annealing. It is concluded that numerical results come, in general, in satisfied agreement with the experimental data.