In recent years, international research and Analysis on the research, development and application of X80 grade large caliber high grade steel pipe conveying seamless pipe steel for natural gas are studied and analyzed. The main results are as follows:
1. development trend of natural gas pipeline
The cost of pipeline construction can be greatly reduced by high pressure transportation and high grade steel pipe. This is the main trend of natural gas pipeline development. The pipe diameter can be reduced by high pressure transportation. The wall thickness of the steel pipe can be reduced by the development and application of the high grade pipe, thus reducing the weight of the steel pipe and reducing the welding time in the construction site, thus greatly reducing the weight of the steel and building cost. According to Canada's pipeline construction statistics, piping materials and engineering design can save 17% to 29.5% of the grade of X80 steel compared with the total of two X70 steel.
Worldwide, X80 grade seamless pipeline steel has been successfully applied. From the middle of the 1980s, the grade of X80 steel began to be studied and tested and used in the early 1990s. So far, about 2000 kilometers of X80 steel pipes have been used in all parts of the world.
3. there are X80 steel grades in the world's main pipeline steel product standards, with clear quality and technical specifications. Japan, Europe, Canada and other countries have large production plant batch supply records, production technology has matured.
4.X80 steel pipe is mainly concentrated in Canada, Europe, the United States and other developed countries, and has accumulated rich experience in pipeline design, construction and operation management.
5. successful experience of international X80 Steel Research and application shows that there is no significant difference in design, production and construction between X80 and X70 steel, and the pipeline has been built and run normally.
In summary：
(1) the selection of X80 high-grade pipe can save a lot of construction cost, which is an important trend in the development of international natural gas pipeline. X80 steel grade is a mature and standard pipeline steel grade in the world. It has mature experience in pipeline design, production, construction and operation.
(2) after many years of domestic research and development, the first test of X80 grade seamless pipe quality index is in line with the X80 pipeline engineering application standard, which requires the physical quality of the steel pipe and the same foreign product as the same kind of pipe.
(3) solved the international X80 pipeline to transport common natural gas road failures. On the basis of analyzing the cracking toughness and crack arrest toughness of X80 grade steel pipe and the safety analysis of pipeline operation, it is safe and feasible to replace the X70 grade pipeline with X80 thin-wall pipe.
(4) the application of X80 pipeline steel will be more extensive in the world. The implementation of X80 pipeline steel pipe engineering application is very necessary. The X80 pipeline for large diameter high pressure gas transmission pipeline will be proposed in the future.
