Determination of the design parameters of X80 cold bending pipe with 1 422 mm diameter in China-Russia Eastern Gas Pipeline

In order to satisfy the actual construction needs of China-Russia Eastern Gas Pipeline Project, it is necessary to research the design parameters of the cold bending pipe of X80 pipeline with 1 422 mm diameter. In this paper, the maximum bending angle of cold bending pipe was calculated using the formula provided in Pipeline-Natural Gas and Oil Pipeline, Part 1: Design and Construction (AS 2885.1-2012), and it is 6.48°. Then, finite element simulation analysis was conducted on the stress and strain in the bending process of cold bending pipe. It is found that when the bending angle is in the range of 6-8°, the pipe is in the elastic-plastic zone, which satisfies the deformation requirements. Finally, verification was carried out in the laboratory and in the test section of the China-Russia Eastern Gas Pipeline. It is shown that the bended 6.4° cold bend pipe has uniform and stable springback and deformation and its ellipticity, wall thickness and inner arc waviness are well controlled, so it satisfies the engineering requirements. Based on the related calculation, analysis and verification, it is eventually determined that the maximum bending angle of X80 cold bending pipe with 1 422 mm diameter in China-Russia Eastern Gas Pipeline is 6° and its curvature radius is not less than 50 times of the steel pipeline OD (71 100 mm). The research results provide the guidance for the construction of China-Russia Eastern Gas Pipeline Project.