EVALUATION OF THE INFLUENCE OF SHUTDOWNS OF A TECHNOLOGICAL PROCESS ON CHANGES IN THE IN-SERVICE STATE OF THE METAL OF MAIN STEAM PIPELINES OF THERMAL POWER PLANTS

摘要

To take into account startups and shutdowns of power-generating units of thermal power plants on the in-service state of the degraded metal of steam pipelines, we propose an approach that assumes the construction of basic relations that take into account the mechanical and process indices of the operated metal. The mechanical index is the efficient threshold of cyclic crack resistance ΔK_(theff) , and the process index is the effective operating time τ_(eff) . Basic dependences ΔK_(theff)-τ_(eff) are constructed from cyclic crack resistance test results of 12Kh1MF and 15Kh1M1F after their different operation histories. It is shown that the modeling of degradation under laboratory conditions can be used for the determination of the current in-service state of the metal after its long operation without mechanical tests.