Cross Weld Creep Comparison of Power Plant Steels CrMoV, P91 and P92

Abstract

Results obtained from high temperature creep tests of ferritic steel CrMoV, P91 and P92 crossweld specimens are compared. Data are presented normalized with the results of the corresponding parent metals in order to compare the materials tested at different temperatures and stresses, and to identify characteristic crossweld material trends. All crossweld failures occurred in the heataffected zone (HAZ) adjacent to the parent metal, known as type IV, at earlier test durations than for the parent material specimens. The relative performance of the crosswelds was found to decrease with decreasing stress. The CrMoV crossweld specimens showed by far the lowest weld strength reduction factors and greatest notch strengthening, determined by testing uniaxially loaded bars with semicircular circumferential notches located in the heataffected zone. The P91 and P92 crossweld specimens were found to have similar (high) weld strength reduction factors and showed little or no notch strengthening. The failure time of a P92 crossweld specimen relative to the P92 parent material could be estimated using data from P91 crossweld and relative parent material tests.