Prediction of thermal histories residual stresses and distortion in welded components

Abstract

During fusion welding the materials experience severe residual stresses RS and cause dimensional inaccuracies It is developed due to uneven temperature distribution of the material that causes transient thermal strains during the movement of the heat source The thermo elastic plastic approach in Finite Element FE is concerned with thermal analysis followed by mechanical analysis in order to predict the residual stresses and distortion The exact prediction of thermal histories residual stresses and distortion of substrate material eliminate the trial experiments that incur huge cost and time The FE simulation of GTA autogenous welding has been performed to predict the residual stresses and distortion Transient thermal analysis has been carried out with different heat source models The sequentially coupled thermo mechanical analysis is carried out to simulate the residual stress and distortion by considering large and small displacement theoriesThe temperature dependent physical and mechanical properties are employed in FE analysis. The conduction convection and radiation heat transfer losses are incorporated during analysis In order to validate the model the experimentation is carried out Thermal histories are recorded using K type thermocouples which are interfaced with the data logger The effect of welding speed on temperature distribution residual stress and distortion is carried out and the results are compared with experimentation The fixtures used in welding are modelled as constrained boundary conditions in FE analysis The effect of constraints has been analysed with respect to residual stress and distortion newline