Assessment of Weldment Specimens Containing Residual Stress

Weldments in components are regions where failures are most likely to occur either by fast fracture, creep or fatigue. These regions could exhibit microstructural inhomogeneity as well as the presence of micro-cracks and residual stresses. Understanding their behaviour is of major source of interest for a range of industries. Creep and creep/fatigue crack growth models as well as residual defect assessment codes need reliable and verifiable material properties data and validated fracture mechanics parameters for use in their predictive methodologies. The research to develop an overall methodology for deriving acceptable data and validated parameters for life assessment analysis has been developing in Europe through a number of collaborative European projects. These have covered both parent as well as weld material of a range of alloys and conditions. Although there is substantial information and data on weld tests available, due to an absence of validated information the industrial community cannot easily use this information with confidence. The present standards, also, do not deal directly with testing of welded specimens and therefore. The Analysis of the results from these projects have been continuing and furthermore have been used to assist in the development of testing standards as well as life assessment codes of practice.