API 5L generally refers to the implementation standard of pipeline steel pipes. Pipeline steel pipes are used to transport oil, steam, water, etc. extracted from the ground to oil and gas industry enterprises. Pipeline steel pipes include seamless steel pipes and welded steel pipes. At present, the welded steel pipes commonly used in oil pipelines in my country include spiral submerged arc welded pipes (SSAW), straight seam submerged arc welded pipes (LSAW), and electric resistance welded pipes (ERW). Seam steel pipe is generally selected when the diameter of the pipe is less than 152mm.
There are many kinds of steel grades of raw materials for API 5L steel pipes: GR.B, X42, X46, X52, X56, X60, X70, X80, etc. Now large steel mills like Baosteel have developed steel grades of X100, X120 pipeline steel. The steel grades of steel pipes are different, and the requirements for raw materials and production are higher, and the carbon equivalent between different steel grades is strictly controlled.
When it comes to API 5L, everyone knows that there are two standards under it, PSL1 and PSL2. Although there is only one letter difference, the content of these two standards is very different. This is similar to the GB/T97220.127.116.11 standard. They all talk about the same item, but the requirements are very different. Let me talk about the difference between PSL1 and PSL2 in detail:
- PSL is the abbreviation of Product Specification Level. The product specification level of line pipe is divided into PSL1 and PSL2, and it can also be said that the quality level is divided into PSL1 and PSL2. PSL2 is higher than PSL1. These two specification levels are not only different in inspection requirements, but also in chemical composition and mechanical properties. Therefore, when ordering according to API 5L, the terms in the contract should not only indicate the usual indicators such as specifications and steel grades. , must also indicate the product specification level, that is, PSL1 or PSL2. PSL2 is stricter than PSL1 in terms of chemical composition, tensile properties, impact energy, non-destructive testing and other indicators.
- PSL1 does not require impact performance. For PSL2, all steel grades except x80, the average value of Akv at 0°C in the full size: longitudinal ≥ 41J, transverse ≥ 27J. X80 steel grade, full-scale 0℃ Akv average: longitudinal ≥ 101J, transverse ≥ 68J.
- The line pipe should be subjected to hydrostatic test one by one, and the standard does not allow non-destructive substitution of water pressure, which is also a big difference between the API standard and the Chinese standard. PSL1 does not require non-destructive testing, and PSL2 should be non-destructive testing one by one.