A series of the work " Assessment of the effect of technological factors on the workability of structural steels of long-term service installations in power engineering and oil-refining industry"

Work number - M 20 FILED

Authors: KrechkovskaH.V., Brukhal M.B., BabiyL.O.,

KarpenkoPhysico-MechanicalInstituteoftheNASofUkraine was recommended.

A series of the work consistof 48scientificpapers, the investigations were carried out during 10 years.

Thescientificresultswhichhavescientificandpracticalsensehavegotina series of papers. The work is aimed to a development of the methods for evaluation of thetechnical state of exploited heat-resistant steels from responsible long-term exploited installations in power engineering and refinery with taking into account of corrosion-hydrogen factor and to provide theoretical and experimental study of the process of cooling solids with different transparency.

Mathematical model is developed to capture thermostressed state of thermosensitive solids of different transparency with consideration of thermal radiation heat transfer.

Degradation of several of heat-resistant steels in-laboratory conditions was simulated by thermocycling of specimens in hydrogen.The method allows to take into account not only hydrogen effect on metal degradation but also technological process shut-downs.An ambiguous effect of hydrogen, absorbed by steels during degradation, on effective fatigue threshold was revealed. Thiseffectwasusedforabasingofcriticaldegradationlevelforshellreactorsteelsofhydrocrackingrefinaryandmainsteampipeline of power stations.

On the base of comparison of the complex of mechanical characteristics concerning to its sensitivity to degradation the expediency of a usage of the local fracture mechanics parameters for degradation evaluation was shown.

Using the mechanical tests of fatigue crack growth resistance in steam pipeline steels after the different time of its service and different number of technological process shut-downs, the base dependencies, which connect the mechanical and technological parameters of steels workability, were built. The method of an assessment of steels current state was developed on this base which takes into consideration its long-term service under elevated temperatures and stresses, hydrogenated working environment and shut-downs. This method was put on the base of the industrial normative Minpalivenergo document СОУ 40.3–0013044–20:2010, which was put into action in2010 year.Followingthisdocumentitispossiblewithoutmechanicaltheteststoevaluatearealtechnicalstateofanalyzingmetal, to baseconclusionsaboutanecessaryofachangeofthecertainelementsandto stateaperiodicity offolloweddiagnosticsfora prevention of unpredicted fracture.

The results a series of the workare important for maintenance of reliable service of hydrocracking refinary reactors and power station steam pipelines.

Its results are published in 48 paper, (including 3papers in foreign journals), 2 – thesis’s. The works of author cite in 50 scientific journals, аtotal index of citing consist of 172 (according to base date of Scopus), h-index=3. Оne normative document and one Ukrainian declarative patent for utility model were obtained.