WEPP AND THE TECH-LEAP OF CHINESE LINE-PIPES

摘要

The WEPP in China, is the longest high-pressure pipeline in the world, eastern part of whose construction has been finished at the 1st Oct. 2003. Up to now, all the pipes of trunk line have been welded and buried under ground, about 740,000 metric tons of which were made by domestic pipe mills. Before this project the capacity of domestic pipe mills is pretty low: the max. O.D. is 711 mm, the max. W.T. is 10.7 mm, and the highest steel grade is API X60. However, the WEPP specification is very high: X70 with about 50% acicular ferrite, O.D. 1016 mm, W.T. 14.6/17.5/21.0/26.2 mm, and more than 190 J CVN value under -15□. This kind of pipe has never been made before in China. However, within about 2 years, Chinese mills successfully fulfilled the development and manufacturing of X70 steel coils and plates, the technical reconstruction of old production lines and installation of the new ones, the scientific research of pipe forming and high speed welding technology and test method, and the technology development of procedure and facilities for inside flow coating and outside 3PE coating. All the above will be detailed in this paper.