The wall thickness and applicable scenarios of API 5L X65 pipeline pipes vary significantly depending on the process. Selection must be based on a comprehensive assessment of engineering pressure, environment, and construction conditions:
Seamless steel pipes (SMLS) have the widest wall thickness range (2.0–120mm), suitable for high-pressure and corrosive environments;
Straight seam submerged arc welded pipes (JCOE) are characterized by thick walls and large diameters (9.5–25.4mm), suitable for long-distance onshore pipelines;
High-frequency resistance welded pipes (ERW) primarily feature thin walls and high efficiency (1.5–15mm), used for conventional transportation of small and medium diameters.
API 5L X65 Line Pipe Dimensions and Wall Thickness Table (ASME B36.10)
| Nominal Pipe Size (NPS) | Outside Diameter (in) | OD (mm) | SCH 40 / STD (mm) | SCH 80 / XS (mm) | SCH 120 (mm) | SCH 160 (mm) | XXS (mm) |
| 2" | 2.375 | 60.3 | 3.91 | 5.54 | - | 8.74 | 11.07 |
| 3" | 3.500 | 88.9 | 5.49 | 7.62 | - | 11.13 | 15.24 |
| 4" | 4.500 | 114.3 | 6.02 | 8.56 | 11.13 | 13.49 | 17.12 |
| 6" | 6.625 | 168.3 | 7.11 | 10.97 | 14.27 | 18.26 | 21.95 |
| 8" | 8.625 | 219.1 | 8.18 | 12.70 | 18.26 | 23.01 | 22.23 |
| 10" | 10.750 | 273.1 | 9.27 | 12.70 | 21.44 | 28.58 | 25.40 |
| 12" | 12.750 | 323.9 | 9.53 (STD) | 12.70 (XS) | 25.40 | 33.32 | 25.40 |
| 14" | 14.000 | 355.6 | 9.53 (STD) | 12.70 (XS) | 27.79 | 35.71 | - |
| 16" | 16.000 | 406.4 | 9.53 (STD) | 12.70 (XS) | 30.96 | 40.49 | - |
| 18" | 18.000 | 457.0 | 9.53 (STD) | 12.70 (XS) | 34.93 | 45.24 | - |
| 20" | 20.000 | 508.0 | 9.53 (STD) | 12.70 (XS) | 38.10 | 50.01 | - |
| 24" | 24.000 | 609.6 | 9.53 (STD) | 12.70 (XS) | 46.02 | 59.54 | - |
Engineering Selection Recommendations
| Manufacturing Process | Typical WT (mm) | OD Range (mm) | Key Advantages | Recommended Applications |
| SMLS (Seamless) | 2.0 – 120 | 21.3 – 1026 | No weld seam, uniform structure, high pressure resistance. | High-pressure station connections, corrosive media transport, urban trunk networks. |
| JCOE (LSAW) | 9.5 – 25.4 (up to 40) | 457 – 1422+ | Thick-walled, large diameter, low residual stress. | National long-distance pipelines, complex terrains (permafrost/mountainous areas). |
| ERW (High-Frequency Welded) | 1.5 – 15 | 21.3 – 609.6 | Low cost, high efficiency, precise dimensional accuracy. | Urban gas distribution, oilfield gathering and transportation, temporary pipelines. |
Mandatory Testing Requirements
| Test Item | PSL1 | PSL2 |
| Hydrostatic Test | Mandatory | Mandatory |
| Non-Destructive Exam (NDE) | Per Contract | Mandatory (100% Ultrasonic or MFL) |
| Charpy V-notch (CVN) | Not Required | Mandatory (Body & Weld) |
| Drop Weight Tear Test (DWTT) | Not Required | Mandatory for OD ≥ 508mm (20") |
| Visual & Dimensional Check | Mandatory | Mandatory |
GNEE API 5L Pipeline factory
FAQ
What is API 5L grade X65 material?
API 5L X65 PSL2 Pipe, API 5L X65 carbon steel or L450 X65 Pipe is an alloy of elements like manganese, phosphorus, sulphur and titanium. The API 5L X65 chemical composition of these pipes make it one of the most valued and versatile pipes ever.
What is the ultimate tensile strength of X65?
Grade X65 indicates 65000 PSI minimum yield strength and 77000 PSI minimum ultimate tensile strength.
What is the difference between API 5L X60 and X65?
API 5L X60: It is commonly used for onshore and offshore pipelines, structural applications, and equipment in the oil and gas industry. API 5L X65: It is primarily used for high-pressure and high-temperature pipelines, especially in demanding environments such as deepwater and arctic conditions.