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Materials ScienceEngineeringSlow CokingMechanical PropertiesLow-cycle FatigueChemical CompositionMechanical EngineeringSolid MechanicsReaction VesselProbability TheoryThermomechanical ProcessingThermomechanical AnalysisChemical KineticsTechnical ApplicationsMechanics Of MaterialsMathematical StatisticsStructural Materials
and thermal deformation [1-3]. Slow coking is a semiperiodical process and, consequently, the variation of the temperature and force factors of deformation is of cyclic nature. During the working cycle of the reaction vessel, the temperature of the vessel shell increases from normal temperature to 500~ followed by holding and subsequent reduction. Therefore, the following forms of deformation can be separated: low-cycle fatigue caused by force factors, thermal fatigue resulting from the effect of thermal cycling, and creep. As shown by experience with the service of the reaction vessels, their service life equals 103 to 3.103 load cycles [2]. This indicates that the shell is deformed in the elastoplastic region. As a result of replacement of certain SCE reactor vessels, it has become possible to examine the physical and mechanical properties, chemical composition, and structure of the structural materials subjected to a specific number of load cycles in service. Table 1 gives data on SCE reaction vessels from which the metal specimens were taken for the investigations. Analysis of the form of the temperature field in the shell of the reactor vessel indicates that the field is highly nonuniform and unstable [4] as a result of the instability of the hydrodynamic conditions of filling with the raw materials. The side supply of the raw materials displaces the trajectory of the immersed jet to the opposite side of the equipment and is the main reason for the asymmetric form of the temperature field. Since the