Creep Rupture of Notched Plate and Cylindrical Specimens of 1Cr-1Mo-1/4V Steel at Elevated Temperatures

Abstract

The objective of the present study was to elucidate the effect of strain restriction resulting from the difference in notched section form of metallic specimens on creep rupture life at elevated temperatures and also the effect of vacuum environment on rupture life. From the results of tensile creep rupture tests on notched plate specimens of 1Cr-1Mo-1/4V steel in both atmospheric pressure and vacuum at 600°Cand of numerical calculations by use of the finite element method, the following conclusions have been derived.
(1) When the present results of notched plate specimens were compared with those of notched cylindrical specimens reported previously, the creep rupture life of a notched cylindrical specimen was longer than that of a notched plate specimen in the region of notch-strengthening, but there was little difference between both data in the region of notch-weakening. This may be interpreted on the basis of the difference in the equivalent stresses or the strains at the notch bottom of cylindrical and plate specimens.
(2) The creep rupture life of a notched plate specimen in vacuum was almost the same as that in atmospheric pressure in the region of notch-strengthening, but in the region of notch-weakening the former was shorter than the latter.