The many heat treatments upon fabrication may deteriorate the tensile properties of the tempered base material or to alter its weldability or toughness. It is essential to take into consideration all heat treatments each zone is submitted to: base metal, heat affected zone, weld metal in order to optimize the global properties of the vessel. Major issues are illustrated by precise examples. An approach based on the equivalent tempering parameter is put forward.
(Online publication April 9 2008)