Keyword: «cold resistance»

The article describes the kinetics of the processes of damage accumulation of railway transport objects, as well as the dominating mechanisms for reaching their limit states. The evaluation is carried out for the characteristics of metal strength along with reliability and safety of structures with a decrease in temperature and their degradation during the operating life. For welded and cast parts, it is proposed to use steels with improved cold resisting properties. The necessity is shown for usage of constructive and technological methods to increase the service life of welded and cast parts. Сформированы актуальные задачи по реализации проекта освоения Севера и Арктики. Actual tasks have been formed for implementation of the project for the development of the North and the Arctic.

Prospects for the development of the Russian Arctic regions by the way of use of new materials and technologies designed to improve the reliability and resource, safety of operation of complex technical systems, such as energy and transport complexes, residential and industrial infrastructure in the extreme environment conditions of the Far East and North, which will allow more efficient development of the new territories and resources of strategic importance, are given.

It is assumed that the decrease in crack resistance at low temperature may be associated with a decrease in the size of the plastic zone. A large plastic zone has the effect of «blunting» the crack tip. With a decrease in temperature, due to an increase in the yield strength and a decrease in the size of the plastic zone, this effect is significantly reduced, which leads to a significant decrease in crack resistance. Using a combination of classical mechanics and fracture mechanics approaches, an associated expression for a crack resistance is obtained. The expression qualitatively describes the experimentally obtained curves of the ductile-brittle transition zone. It is shown that, in addition to such factors as the scale effect, features of the crystal structure of the metal, the parameters of classical mechanics and fracture mechanics can make a significant contribution to the phenomenon of cold brittleness.