Article ID Journal Published Year Pages File Type
788538 International Journal of Pressure Vessels and Piping 2009 7 Pages PDF
Abstract

In structural welded joints after long-term service at high temperature, fracture occurs mainly in the fine-grained heat affected zone (HAZ). Recently, the nucleation and growth of creep voids in the fine-grained HAZ of weldments, recognized as Type IV fracture, have become an important problem for low alloy ferritic heat resisting steels. In this paper, a new constitutive model was introduced to analyze the creep damage development in HAZ induced by void growth. This model is based on the equations of continuum damage mechanics (CDM) and combines a micromechanism-based method to account for the void growth process, which is different from the previous studies of creep damage. By coding a user-defined material subroutine (UMAT) in the FEA software ABAQUS, the proposed model was used to investigate the creep damage development in HAZ of a multi-material cross-weld specimen and a medium bore welded branched pipe where four different material properties: base material, coarse-grained HAZ, fine-grained HAZ, and weld material, were taken into account.

Related Topics
Physical Sciences and Engineering Engineering Mechanical Engineering
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