Kinetics of crack development in power engineering steels under high-temperature creep

Abstract

Features of crack development kinetics in steels under creep are investigated from positions of fracture mechanics. It is shown that the creep crack growth rate can be approximated by a power dependence on parameter C* or on the stress intensity factor. At the same time, exponents of these dependences are a function of characteristics of long-term strength or material creep. For description of the creep crack rate, it is proposed to use the reduced stress intensity factor, which takes into account the character of the stress distribution in the design section and the crack development time. The experiment verifies the advantages of using the reduced stress intensity factor as a correlation parameter describing the creep crack growth rate.