Simulation of role of precipitate in creep void occurrence in heat affected zone of high Cr ferritic heat resistant steels

A three-dimensional (3D) precipitate and matrix model was used to investigate the role of precipitates as nucleation sites of creep void in the heat affected zone (HAZ) of a welded joint of high Cr ferritic heat resistant steels at high temperature and low stress. Several factors affecting creep void initiation, such as Young's modulus of precipitate and precipitate size, were studied. The material properties of the matrix were investigated for the regions of coarse grained HAZ, fine grained HAZ and base metal in the welded joint. The results show that creep void occurs easily in the fine grained HAZ region because of the deterioration in material properties and coarsened precipitates in this zone.