Research of the temperature relaxation process of tension in steels

The purpose of the work is to research the tension relaxation mechanism using the example of steel 08X15H24B4TP and finding an acceptable theoretical model describing this process. Thus, the problem can be formulated as the derivation of an expression describing the dependence of the tension on time in a sample that is given the initial deformation at a certain temperature (the initial tension), after which the deformation and temperature remain constant and the process of tension relaxation occurs. Such an impact corresponds to the operating mode of many parts and components in engineering, as well as the operation of reinforcement with initial tension in the event of a fire. The results of a researching of tension relaxation in steel 08X15H24B4TP under conditions of state with initial tension and high-temperature impact are presented. The conditional service life of the samples is determined, commensurate with the actual service life of machine parts, components and building structures. Conclusions are given about the timing, depending on the model parameters. Based on the assumption of a linear temperature effect on the tension relaxation process, a model is shown that describes with sufficient accuracy the relaxation of tension in steel with allowance for the temperature effect. The parameters of this model for steel grade 08X15H24B4TP are determined. (paper)