API 5L Line Pipe has grades from B to X70 in common use pipelines, so Grade X65 pipe is one of the premium class material.
Same with other API 5L pipe, X65 pipe has two product specification levels of PSL1 and PSL2, and in some cases required for sour service use.
Supply for API 5L X65 pipe
Standard and Grades: API 5L X65
Product Specification Level: PSL1, PSL2
Material: NACE MR 0175 complied, for sour service
Working Environment: H2S corrosion
Manufacturing processes: Welded ERW, LSAW, SSAW, and Seamless
Sizes Range: 1” to 30”.
Common Sizes Applied: 2”, 3”, 4”, 6”, 8”, 10”, 12”, 14”, 16”, in SCH 20, SCH 40, SCH STD, SCH 80, SCH XS, SCH 160, SCH XXS, etc.
API 5L X65 pipe for sour service use is more strictly than above two grades, so when refers to sour service pipe, it shall comply all of the PSL2 pipe requirements.
API 5L X65 PSL2 sour service pipe (X65QS/MS, L415QS/MS), C maximum is 0.10, Mn ≤ 1.45, Si ≤ 0.45, P ≤ 0.020, S ≤ 0.002, V ≤ 0.10, Nb ≤ 0.08, Ti ≤ 0.06, CEPcm ≤ 0.22. Sour service line pipe requires a strictly control on the chemical composition. So to protect pipe from corrosive environments like H2S, low carbon and low CEPcm value will reduce the martensite which sensitive to H bubble, so to improve the corrosive resistance to H2S. Moreover, P and S also should be less than normal line pipes. Out of these, the mechanical strength is the same with API 5L X65 PSL2 steel line pipes.
According to the data, 74% of pipeline accidents were caused from pipe corrosion, and H2S is the mainly corrosion types in corrosive environments. So it is very important to manufacture steel line pipe for sour service. API 5L X65 PSL2 Pipe for sour service, material also comply to NACE MR 0175.
API 5L Grade X65 or L450 PSL1 pipe is normal carbon steel material among the tree types and for common use, (None corrosion environment but in high pressure pipelines required a certain mechanical properties). so it has the highest content of C, Mn, Si, P, S than the other two types. (These chemical elements is lower the steel is purer). X65 PSL1 pipe Minimum yield strength is 450 Mpa (65300 psi), minimum tensile strength 535 Mpa (77600 psi).
For API 5L X65 PSL2 (API 5L X65Q.M or L450Q/M), C ≤ 0.18, Si ≤ 0.18, Mn ≤ 1.70, P ≤ 0.025, S ≤ 0.015, all of these elements have less value than PSL1. Since PSL2 requires CEq ≤ 0.43, and CEpcm ≤ 0.25. (Ceq is carbon equivalent, it affects the steel welding performances, strength value). And because of this, API 5L X65 PSL2 pipe (welded and seamless) mechanical strength has a maximum limits: yield strength 450 – 600 Mpa (65300 psi to 87000 psi), tensile strength 535 to 760 Mpa (77600 psi to 110200 psi)
API 5L Grade X65 PSL1/PSL2 Seamless Carbon Steel Line Pipe is designed to be used as most economical and safe way of transporting oil and gas. The significant number of accidents caused by failures of pipelines is due to corrosion. Plastic deformation can modify the mechanical properties of these pipelines, steel's corrosive behavior when deformed plastically is important to avoid failures.
