It is impossible to improve the quality of the machines, to increase their reliability and lifetime if the working conditions and the properties of the material are not analyzed. We must know the type of the material (hardening, softening or cyclically stabile), what is chosen for the constructions in low cycle loading, because strain and stress change during the exploitation and depend on this type. If we know the type of the material, we can determine the possibility of its application in concrete exploitation conditions. Real working conditions of the most constructions are close to loading with limited strain (hard straining), because elastic and plastic deformation is met in the zones of crack and stress concentration, that are surrounded with elastically deformed material. The low cycle loading curves parameters A, and are used for the computation of elastic plastic strain curves. These parameters are obtained from the soft low cycle loading results in many cases. The other possible ways for the determination of parameters A, and are shown in this work. The most investigated materials had the initial instability in the interval . For more objective evaluation of stress strain curves parameters A, and , all values of width of hysteresis loop up to semicycle were rejected as insignificant in comparison with the rest lifetime in cycles range . The parameter for the evaluation of hardening (softening) intensity was determined, when the values of... [to full text]