Ripey I. Serviceability of structural materials during long-time operation of FPP turboagregate

The structural materials of FPP turboagregate. The regularities of the influence of the service and model environments on the degradation, structure and properties change of the structural materials of FPP turboagregate during long-time operation have been determined. The X-ray, phase carbide and fractography analyses; electrochemical investigation and mechanical testing of the crack growth resistance at cyclic and static loading. For the first the determining role of starting-stoping on the crack propagation rates in the turbine cast elements was established. It has been found, that high-strength 12Х18АГ18Ш steel for retaining rings is more resistant to hydrogen embrittlement and hydrogen fatigue than 60Х3Г8Н8В steel. It has been determined, that chloride and hydrogen-containing environments increase M1 copper degradation caused by the higher crack propagation rate and due to embrittlement of copper winding. It has been determined that the increase of strength level of rotor steel due to decrease offatigue fracture resistance in hydrogen-containing environment; surface treatment (turning and shot-peening) increased long-term strength of 38XH3MФA steel. The results have been used in Minpalivenergo Lviv SB and Dobrotvir FPP and as well as Burshtyn FPP.