Syrotyuk A. Determining of condition of surface crack nucleation under cyclic deforming in steels for power generating equipment in aqueous environments

The dissertation contains the grounds and new solution of scientific and technical problem for determining of conditions and criterion of surface crack nucleation in steels for pipelines of power generating equipment. These conditions and criterion were evaluated under relationship of physicomechanical parameters of surface state and mechanism of influence of operating environment. For corrosion fatigue assessment a new parameter is proposed that is some characteristic value of applied stress within loading cycle beginning from which the significant electrochemical activation of deformed surface is occurred. The model and criterion of surface corrosion fatigue crack nucleation are developed as function both characteristic stress and parameters of electrochemical dissolution of cyclically deformed surface. The admissible crack depths in pipelines internal surfaces with steels 12Kh1MF and 08KhN12T were determined with takes into account of planned terms of their exploitation and factors of operating environments