Residual stress simulation in welded sections of P91 pipes

Abstract

In this paper, a brief review of weld simulation and residual stress modelling using the finite element (FE) method is presented. The method of FE analysis of welded sections of P91 pipes is described. Mechanical and thermal material properties used in the modelling are related to a general P91 parent steel database, generated from available literature. Two specific FE examples are described, which are axisymmetric butt welds in P91 steel pipes having a 4 or 36 pass weld in a pipe with wall thickness of 7.1 or 40.0 mm, respectively. As part of a parametric study, eight more FE models with inside radius to wall thickness ratio ranging from 1 to 100 have been analysed to investigate the effect of pipe diameter on residual stresses. The thermal analysis has revealed temperature contours, which indicate the size of the weld region and the heat affected zone (HAZ). Residual axial and hoop stresses obtained from the analysis have been shown for a range of pipe diameters for the two pipe wall thicknesses. Trends of behaviour of residual stresses have emerged for the set of material properties implemented in the FE analysis. In addition, the effect of pipe diameter on the residual stresses has been presented.