Stress-corrosion is the most frequent cause of failures on the linear part of the main gas pipelines (in central Russia — 50 % causes of emergencies occurrence). For gas pipelines of the Far North the frequency of accidents due to corrosion damages is low. Stress-corrosion phenomenon on the gas pipelines of the Republic of Sakha (Yakutia) was not observed before the above considered case. This fact can be explained by the influence of the external conditions of loading on the frequency of stress-corrosion accidents: large majority of accidents due to stress-corrosion falls within the most loaded gas pipelines with the diameter of 1420 and 1220 mm. The article reviews stress-corrosion cracking revealed in 2019 on the main gas pipeline of Republic of Sakha (Yakutia) during study of the causes of the main gas pipeline destruction after operation of more than 50 years. Gas pipeline destruction occurred at the site of three consistently welded pipes with the diameter of 530 mm. Destruction centers were corrosion ulcers formed on the mechanism of galvanic corrosion at contact of pipes with degradation during long operation of bitumen isolation with steel bars. Through cracks of corrosion cracking with a length of 28 and 70 mm normal to the direction of the main crack were found in the congestion of corrosion ulcers. The primary corrosion crack was formed under the influence of localization of corrosion process and pulling stresses due to the development of ulcer corrosion. Cracks extended along the body of the ferrite grains along the action of maximum pulling stresses were not structurally-selective and not the seats of destruction. Corrosion crack is developing as a continuous electrochemical process intensified by the imposed tensile strength.
Read in №7 of 2019 year "Corrosion Damage to the Pipes of the North Gas Pipeline"
23 июл 2019
RAS Professor, Dr. Sci. (Eng.), Director Federal Research Centre «The Yakut Scientific Centre of the Siberian Branch of the Russian Academy of Sciences», Yakutsk, Russia
Cand. Sci. (Phys.-Math.), Assoc. Prof., Lead Researcher, email@example.com Federal Research Centre «The Yakut Scientific Centre of the Siberian Branch of the Russian Academy of Sciences», Yakutsk, Russia
Graduate Student North-Eastern Federal University in Yakutsk, Yakutsk, Russia