Estimation of the Failure Time for Low-Carbon CrMoV Steels in Creep Condition Using Modified Kinetic Theory Based on Microstructural Parameters

摘要

The decreases of creep resistance can be in most cases, attributed to microstructural degradation in CrMoV steels, such as perlite degradation, carbides precipitation, etc. It is a usual practice to employ a statistical approach to define relationship between some parameters that characterize microstructural degradation and changes in creep resistance of the material. However, statistical analysis of the physically significant parameters that characterize microstructural degradation is usually not straightforward because of the lack and/or unreliability of experimental creep data for most of the materials. In this paper we propose a new approach that is based on determination of the materials strength using modified kinetic theory (based on Zurkov relation). The elementary destruction act is entirely defined in this model from physical point of view, as a result of thermal fluctuatioris of the atoms. This approach based on the microstructural parameters and modified kinetic theory of strength is used to estimate time to failure of the CrMoV steels in high-temperature creep conditions.