Study on Creep Rupture of Notched Cylindrical Specimens of 1Cr-1Mo-1/4V Steel at Elevated Temperature

Abstract

From the tensile creep rupture tests for unnotched and round notched bar specimens of 1Cr-1Mo-1/4V steel at 600°C and the numerical calculation results by using finite element method, the following are concluded: (1) The material tested has the transition phenomena from notch-strengthening to notch-weakening at elapsed time of about 120 hrs. The rupture ductility of the material remarkably decreases after elapsed time of this transition. (2) In the region of notch-strengthening, the levels of the equivalent stress and the strain at the notch root of the notched specimen are lower than those of the notched specimen under the same nominal stress. This holds also in the case of hydrostatic stress at the notch root. On the contrary, the quantitative relation mentioned above is reversed in the notch-weakening. The former is one of the important factors determining the notch-strengthening, while the latter is a factor for the notch-weakening.