Keyword: «low climatic temperatures»

Examples of destruction of welded joints of sections of main gas pipelines in Yakutia under the influence of fields of residual welding stresses are considered. The results of experimental studies of residual stress fields of welded joints of plates made by arc welding under conditions of low climatic ambient temperatures are discussed. The mechanism of the influence of residual stresses on the occurrence of additional plastic deformations in the zones of welded joints after welding under conditions of low climatic temperatures is presented.

The article studies the influence of low-frequency modulated current welding modes on the structure of welded joints of structural low-alloy steels. The welding process takes place in low climatic temperatures. For a comparative analysis of the structure, DC welding was also carried out. The structure was characterized by optical and scanning electron microscopy. The features of the influence of the modulation frequency of the welding current and the ambient temperature on the microstructure of welded joints have been revealed. Comparative structural analysis showed that the low-frequency range of pulsed changes in the energy parameters of the mode provides the most favorable structure of welded joints made of low-alloy steels. The optimal pulse repetition frequency (1.67 Hz) was revealed when welding with modulated current in a low-temperature environment (up to -45°C), at which the most favorable dispersed structure of the welded joint is formed.

The paper substantiates the direction associated with the solution of the interdisciplinary problem of finding ways to improve the reliability and survivability of resource-determining parts and products of equipment operating in the conditions of natural low climatic temperatures of the Northern and Arctic re-gions of the Russian Federation. Prompt provision of services for the repair of worn-out equipment reduces the costs of downtime of production facilities operating in conditions of low climatic temperatures: marine and river marine equipment, port infrastructure, mining, construction and installation, automotive and road construction equipment, pipeline and railway transport. The paper substantiates the need for scientifically based support of the tasks to be solved, not only for the conditions of stationary repair and restoration and welding and assembly complexes of wear-out parts and products of equipment of northern execution, but also for the conditions of their use in mobile complexes.