Abstract

The standard method of testing cylindrical specimens for creep under extension is not accurate enough at creep rates of approximately 10 -6 percent/h or less, and the long-term creep characteristics of metals given in the reference literature for boiler and turbine materials [i] usually lead to stresses at the level of the creep limit ~c (corresponding to 1% deformation in 105 h) or higher. Moreover, the stresses acting in structures operating under conditions of creep, e.g., in boiler turbine construction, are usually set below Zc, and their average level amounts to approximately 0.4-0.7 ~c" Extrapolation of the reference data is used to calculate the creep in a structure operating under such low working stress levels. Thus, data on the minimal creep rates for low stresses are obtained by linear extrapolation against double logarithmic coordinates, which corresponds to the assumption of a power relationship between the stress z and the relative creep rate }:

Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call