Deformation Histories Relevant to Multipass Girth Welds: Temperature, Stress and Plastic Strain Histories

Abstract

Residual stresses predicted from welding simulations are known to be sensitive to the choice of material model. Recent work has shown large differences in the predicted residual stress profile when different types of hardening model are used (isotropic, kinematic or mixed models). More information is required regarding the exact deformation conditions that exist during welding. We consider finite element models of two multi-pass, stainless steel girth welds. Temperature, stress and plastic strain histories are recorded in the weld material and in the heat affected region (HAZ). Material in the weld and HAZ is observed to undergo three to five cycles of active plastic deformation followed by thermal cycling that is purely elastic. The stress state varies from biaxial compression to triaxial tension. These deformation histories are used as the basis for a discussion of the formulation of a suitable material testing schedule and subsequent constitutive modelling.