NATURE OF CHANGES OF RESIDUAL STRESSES IN TAILS AFTER STATIC AND FATIGUE TYPES OF LOADING

The study objective is to determine the residual stresses in the working part of tails after various types of heat treatment, made from 40Kh and 55 types of steel. To achieve this goal, the following tasks are defined: to develop a method for determining internal residual stresses, to analyze the fractures of samples obtained using three types of technological hardening, and to determine the longitudinal and circumferential residual stresses in the samples. The main research method is the analysis of experimental data obtained during the study of an experimental batch of samples hardened under various parameters. The research methods also include both a theoretical analysis of existing scientific works on this topic and practical experiments to determine residual stresses in the samples. The novelty of the work is in obtaining quantitative results from the study of residual stresses in tails after various types of treatment. This paper presents a method for determining surface residual stresses and the results of their study in tails manufactured using various types of heat treatment. The studies were carried out on tails immediately after manufacturing (at the delivery stage), as well as after static and fatigue tests. The obtained results make it possible to assess the change in residual stresses by experimentally modeling the operational effects on the object under study.