The effect of weldments in service performance of high temperature components has been subject to intensive research due to the fact that in the majority of cases where high temperature failure occurs, defects predominate in the vicinity of weldments. Cracking occurs in service due to reduced creep ductility of HAZ and weld metal due to ageing in service, combined with the action of multi-axial stress fields that reduce the creep ductility further. The defects detected or assumed to exist through minimum allowable limits of detectable flaws using non-destructive testing methods is required for structural integrity and residual life assessment of high temperature components. The assessment relies on information obtained from the material's high temperature tensile, uniaxial creep, crack initiation and growth properties. The concepts used for time dependent fracture analysis of homogeneous bodies are commonly applied for creep crack growth in weldments that show multi-crack initiation and crack branching. This calls for study of deformation behavior and applicability of fracture mechanics parameters for high temperature assessment of weldments. The present paper reports on the material behavior and methodology followed for testing and assessment of the high temperature steel weldments.
展开▼
