INVESTIGATION ON THE CHARACTERISTIC OF RESIDUAL STRESS DISTRIBUTION IN THE DISSIMILAR METAL WELDS OF A SMALL BORE PENETRATION NOZZLE BY THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS

In this study, three-dimensional finite element residual stress analysis of a small bore penetration nozzle was performed using the commercial finite element program, ABAQUS. Comparing with the real PWSCC (primary water stress corrosion crack) history, it is identified that the finite element analysis is valid in the viewpoint of PWSCC initiation and growth. Parametric finite element residual stress analysis was systematically implemented in order to investigate effect of the geometric variables including nozzle outer diameter/thickness, buttering thickness, angle between central axes of head & nozzle, etc. on the residual stresses. As a result of the parametric analysis, it is found that effects of the nozzle outer diameter and the angle between central axes of head & nozzle on the maximum residual stress generation location and magnitude are significant while effects of the head thickness, the buttering thickness, the weld depth, and the nozzle thickness to outer diameter are insignificant.