A viscoplastic model for numerical simulation of welding and post-weld heat treatment

A viscoplastic model is developed to perform numerical simulation of welding and post-weld heat treatment in an industrial context. It can describe with the same formalism the steer inelastic behaviour all along the process: time-independent plastic at low temperature, viscoplastic at higher temperature and viscous fluid for melted metal. Applied for the description of the French vessel steel over a temperature from 500 degrees C to 1300 degrees C while this latest is viscoplastic, it provides a good fitting of creep curves with the primary and the secondary creep. Furthermore, the model identified with the creep-curves well reproduces tensile tests and relaxation tests. The model allows to involve metallurgical transformation effects. It is incorporated within a general modelling build to describe the whole mechanical behaviour during welding process, with temperature and metallurgical coupling.