CREEP ANALYSIS AND FAILURE PREDICTION OF WELDS

This paper describes some aspects of research work related to the performance of welds at elevated temperature. A twomaterial crossweld specimen has been used to investigate the interaction effects of the material properties and specimen geometry on the creep stress or strain rate distributions. A general form of the creep behaviour of multimaterial components was established, which has been shown to be an effective tool for parametric analysis of welds. Methods used for generating the material constants in the constitutive equations for different material zones of welds have been developed; these are based on the experimental results of uniaxial, crossweld and impression creep tests. To illustrate the work, the prediction of the failure life of a serviceaged, thickwalled, CrMoV pipe weldment is presented and a simplified procedure which relates the failure lives of weldments and crossweld specimens based on damage modelling is described.