Study of structure and properties of pipes of urban gas distribution system after long-term operation

Pipes of the gas distribution system of the city of Minsk have been studied after operation for 50 years. It was established that the main defects of pipes were surface defects formed during their production, and corrosion damages of the pipe surface were associated with a violation of the continuity of the waterproofing. The structure of the pipes as a whole meets the requirements for steel 20 and 10, including taking into account the main standards (GOST 8233-56, 5639-82, 5640-68, 1778-70). The mechanical properties of the metal on sections of the pipeline without damage meet the requirements for carbon steels. In this case, the stress level is below the yield point. In the absence of external mechanical influences, maintaining the tightness of the insulating coating can be considered a sufficient sign of extending the life of gas pipes.