The paper there presents the analysis of low-cycle fatigue test results of 30 HGSA alloy steel obtained with the use of two methods. In the standard method, fatigue tests were performed with the use of many specimens, and in the simplified method, the results were defined in an incremental step test using one specimen. Test results were analysed taking into account the influence of loading form on the course of a stabilization process with defined material data. The analysis of the stabilization process in diversified conditions of loading was performed by comparison of the stress amplitude CTa and strain amplitude Eap for the same levels of total strain amplitude Eac• Basing on the tests, one could state that both methods of defining the cyclic properties lead to qualitatively and quantitatively convergent results. The results exhibit qualitative similarity as far as the character of courses of changes determined in different periods of life of n' and K' parameters of the cyclic strain chart is concerned, and quantitative similarity of the values of determined parameters.

Results and low-cycle fatigue tests analysis of 45 steel in conditions of block programmed loading with a different sequence of levels were presented in the paper. During tests four types of programs were applied: gradually increasing, gradually decreasing, gradually increasing and decreasing, and irregular. The sequence of levels in the block loading program was the parameter, which diversified the applied programs. The results of tests were analysed in the aspect of influence of loading program character on the course of the stabilization process. The analysis of the stabilization process was performed by comparing the stress loading amplitude for the chosen levels of the program in the following blocks. The hardening index was proposed as a description of the stabilization process. The comparative analysis showed similarity of the stabilization processes both under the programmed and the constant - amplitude loading.

The paper presents comparative analysis of the results of low- cycle fatigue experiments on specimens made of 45 steel under uniaxial loading and bending. The analysis involves, among other things, the cyclic properties and the fatigue life of the specimens in a wide range of loading conditions. The experimental techniques used during bending enabled us to estimate the influence of strain distribution on fatigue life. The materials data obtained under the loading conditions mentioned above were employed to estimate the fatigue life of the structural elements. The results of experiments and calculations are presented in the form of fatigue curves. They also show the influence of axial loading and bending on the accuracy of the calculations.