Steel for oil and natural gas transmission pipeline is an important steel type integrated with equipment and technology, which is a sign of the technical level of iron and steel industry. The production of high level API 5L X80 pipeline steel is also the embodiment of the comprehensive strength of iron and steel enterprises. API 5L X80 pipeline steel is widely used in gas transmission pipeline engineering and oil pipeline engineering because of its high strength, high toughness and excellent weldability. Due to its mature production process, API 5L X80 pipeline steel is generally listed as the preferred steel grade for oil and gas transmission pipeline in developed countries in the early 21st century.

For high level API 5L X80 pipeline steel, because the pipeline runs in the area or sea floor with complex geographical environment and low cold climate conditions under high pressure, long-distance transportation of oil and gas with complex and corrosive components requires API 5L X80 pipeline steel to have high strength and toughness, especially low-temperature impact toughness and crack arrest toughness, anti-corrosion medium hydrogen induced cracking (SCC and HIC), good welding performance, etc. Therefore, it is of great significance to master the relationship among composition, process, structure and properties for the development of high level API 5L X80 pipeline steel with acicular ferrite structure, high strength, high toughness, good welding performance and corrosion resistance.