Effect of transformation induced plasticity on residual stresses: application to the welding repair of ferritic steel

Welding repair techniques, such as “temper bead welding” (TBW), have known significant development during the last decades. These techniques produce beneficial metallurgical transformations during in-situ modification or repair of thick pressure vessel equipments. This approach relies on a multipass welding strategy in order to thermally affect the heat-affected zone (HAZ) of the base metal in order to induce tempered or even grain refinement and without any use of post weld heat treatment. The main objective of this work is to exploit wisely the effects of low temperature transformations (LTT) and transformation-induced plasticity (TRIP) in the aim to reduce the high residual stress levels generally observed during a multipass welding repair operations. To do so, a thermo-metallurgical-mechanical simulation of the repair welding operation is designed and need to be fully calibrate with experimental results.