Line pipe is a dedicated pipe which can transport oil, steam or water to oil and gas industry enterprises. Pipeline includes seamless and welded steel pipe which the ends are flat end, threaded end and the socket end. The connection mode is welding, connection, socket connection and so on.
API is known to everyone in the steel industry and it has long been inscribed in the hearts of every person in the steel tube. API refers to the American Petroleum Institute, while API 5L is the production execution standard of pipe line.
API 5L pipe production is currently using micro alloy heating treatment process. The production costs of seamless stainless steel pipe are significantly higher than the welding pipe and with the increase of steel grade, the limit of carbon content is more and more strict. At present, all the major manufacturers carry out research work in order to improve the corrosion resistance of the pipeline and ensure the stable performance in low and high temperature.
PSL is referred to as the level of product specification. The product specification of the pipeline is divided into PSL1 and PSL2, there is a difference of only a single word, but the content of these two standards are completely different. The quality level of PSL2 is higher than that of PSL1, these two standards are not only different from the inspection requirements, but also the chemical composition and mechanical properties are different.
| Steel grade | C | Mn | P | S | Ti | |
|---|---|---|---|---|---|---|
| Max | Max | Min | Max | Max | Max | |
| A25 | 0.21 | 0.60 | - | 0.030 | 0.030 | - |
| A25 | 0.21 | 0.60 | 0.045 | 0.080 | 0.030 | - |
| A | 0.22 | 0.90 | - | 0.030 | 0.030 | - |
| B | 0.28 | 1.20 | - | 0.030 | 0.030 | 0.04 |
| X42 | 0.28 | 1.30 | - | 0.030 | 0.030 | 0.04 |
| X46,X52,X56 | 0.28 | 1.40 | - | 0.030 | 0.030 | 0.04 |
| X60 | 0.28 | 1.40 | - | 0.030 | 0.030 | 0.04 |
| X65 ,X70 | 0.28 | 1.40 | - | 0.030 | 0.030 | 0.06 |
| Steel grade | C | Mn | P | S | Ti |
|---|---|---|---|---|---|
| Max | Max | Max | Max | Max | |
| B | 0.24 | 1.20 | 0.025 | 0.015 | 0.04 |
| X42 | 0.24 | 1.30 | 0.025 | 0.015 | 0.04 |
| X46,X52,X56,X60 | 0.24 | 1.40 | 0.025 | 0.015 | 0.04 |
| X65,X70,X80 | 0.24 | 1.40 | 0.025 | 0.015 | 0.06 |
| Steel grade | Yield strength | Tensile strength | ||
|---|---|---|---|---|
| Min | Min | |||
| psi | MPa | psi | MPa | |
| A25 | 25000 | 172 | 45000 | 310 |
| A | 30000 | 207 | 48000 | 331 |
| B | 35000 | 241 | 60000 | 414 |
| X42 | 42000 | 290 | 60000 | 414 |
| X46 | 46000 | 317 | 63000 | 434 |
| X52 | 52000 | 359 | 66000 | 455 |
| X56 | 56000 | 386 | 71000 | 490 |
| X60 | 60000 | 414 | 75000 | 517 |
| X65 | 65000 | 448 | 77000 | 531 |
| X70 | 70000 | 483 | 82000 | 565 |
| Steel grade | Yield strength | Tensile strength | ||||||
|---|---|---|---|---|---|---|---|---|
| Min | Max | Min | Max | |||||
| psi | MPa | psi | MPa | psi | MPa | psi | MPa | |
| B | 35000 | 241 | 65000 | 448 | 60000 | 414 | 110000 | 758 |
| X42 | 42000 | 290 | 72000 | 496 | 60000 | 414 | 110000 | 758 |
| X46 | 46000 | 317 | 76000 | 524 | 63000 | 434 | 110000 | 758 |
| X52 | 52000 | 359 | 77000 | 531 | 66000 | 455 | 110000 | 758 |
| X56 | 56000 | 386 | 79000 | 544 | 71000 | 490 | 110000 | 758 |
| X60 | 60000 | 414 | 82000 | 565 | 75000 | 517 | 110000 | 758 |
| X65 | 65000 | 448 | 87000 | 600 | 77000 | 531 | 110000 | 758 |
| X70 | 70000 | 483 | 90000 | 621 | 82000 | 565 | 110000 | 758 |
| X80 | 80000 | 552 | 100000 | 690 | 90000 | 621 | 120000 | 827 |
Each line pipe is required to do the hydrostatic test, and the standard is not allowed nondestructive testing replace the hydraulic pressure test.
PSL1 does not require nondestructive testing, but each pipe of PSL2 is required for nondestructive testing.
The impact performance test of PSL1 has no requirements.
All steel grade except X80 in PSL2: Test temperature is 0℃, the minimum average value of the full size longitudinal sample is not less than 41J, the lowest average value of the full size horizontal sample is not less than 27J. X80 grade steel: Test temperature is 0℃, the minimum average value of the full size longitudinal sample is not less than 10J, the lowest average value of the full size horizontal sample is not less than 68J.
