China Petroleum Pipeline Bureau Engineering Co., LTD. Pipeline Planning Institute and Tsinghua University in Hebei Qingxian Bohai Oil Equipment Production Co., LTD., successfully completed D1422x1219X80(pipe diameter 1422x1219mm, X80 steel class) hydraulic explosion test and stress test in low temperature environment (-45℃). It marks the successful research and development of the low temperature, high pressure and large caliber pipe fittings, which fills the gap in the research and development category of this type of pipe fittings in our country. The new product represents the highest equipmen - ment and production level of pipe fittings in the long - distance pipeline system in China. It will be used in the construction of the east line natural gas pipeline project between China and Russia, and lay the foundation for the construction of the cold regional pipeline in the future.

The China-Russia Eastern Route (Heilongjiang-long section) passes through the cold areas of Heilongjiang and Jilin provinces, with the lowest temperature of -48.1℃ at the pole. Because the winter is cold and long, if the insulation and heat tracing method is adopted in the station, not only the energy consumption is high, but also the inspection and protection work volume is large. Therefore, the non-insulation and heat tracing skill plan is selected, and the planned temperature of the pipe fittings used in the station reaches -45℃. At present, the domestic pipe fittings (three links) products can not cover up to -45℃, which cannot satisfy the construction demand of the eastern line between China and Russia. Moreover, there is no precedent for the successful use of X80 pipe fittings in this planning temperature. Therefore, it is necessary to study the data composition, processing, welding skills and quality control methods of the pipe fittings (tees) required for the construction of the China-Russia eastern route, and declare the pipe fittings (tees) products satisfying the planning conditions of the China-Russia eastern route.

In 2016, CNPC established a research group, and the Pipeline Planning Institute jointly launched the joint stock company project of "Research and Development of D1422x1219X80 three-way links for low temperature environment (-45°) in China-Russia East Route stations and yards", focusing on the research and development of D1422x1219X80 three-way products.

Long according to the deputy project, master of petroleum engineering construction of career planning, pipes, sarft wen-wei zhang, vice President of the introduction, research on low temperature failure mechanism of brittle fracture of pipe fittings and avoid the manipulation of the brittle fracture criterion analysis, put forward scientific and reasonable to avoid fitting attack brittle fracture of the manipulation of the target, successively compiled code 6 department; Research on data composition, processing, welding skills and quality control methods of pipe fittings; Two rounds of industrial trial production, hydraulic explosion test and stress test were carried out. The new D1422X80 tee product was successfully opened and announced for low temperature environment (-45℃) in the station.