Diagnostics of the Structural-Mechanical State of Steels of Steam Pipelines by the Coercimetric Method and Prediction of Their Service Life

Abstract

We investigate the chemical and phase compositions, structural morphology, and physicomechanical properties of 12Kh1MF and 15Kh1M1F steels from the bends of steam pipelines of thermal power plants after operation for 175 – 280 ⋅ 103 h. The possibility of diagnostics of the structural-mechanical states of the steels of steam pipelines after long-term operation is experimentally justified by measuring their coercive force H C . We propose a method aimed at the prediction of the residual service life on the basis of the dependences of H C on the operating time and the number of startups and shutdowns of the steam pipelines of TPP. We state that it is necessary to form a new database of correlation dependences of the properties of heat-resistant steels degraded in the process of operation on their structural-phase state and microscopic defects because the dependences known for these steels in the initial (as-delivered) state are inapplicable for the proposed diagnostics.