L360 is the metric designation of API 5L X52 line pipe steel. The letter "L" represents line pipe, while "360" indicates a minimum yield strength of 360 MPa, equivalent to 52,000 psi (52 ksi), which gives the X52 designation.
As one of the most commonly specified pipeline steel grades, L360 provides an excellent balance of strength, toughness, weldability, and cost-effectiveness for oil, gas, and water transmission pipelines.
GNEE Pipe supplies API 5L L360 (X52) line pipe in seamless, ERW, and LSAW production forms, available in PSL1 and PSL2 quality levels, with certification according to API 5L and GB/T 9711 standards.
Need a quote for your pipeline project? Contact our engineering team for pricing and technical support within 24 hours.
Key Specifications
| Parameter | Specification |
|---|---|
| Standard | API 5L (latest edition) / GB/T 9711 |
| Grade | L360 / X52 |
| PSL Level | PSL1 and PSL2 available |
| Production Forms | Seamless (SMLS), ERW, LSAW |
| Size Range | NPS 8" – 36" (OD 219.1 – 914.4 mm) |
| Length | SRL 5.8–6.0 m, DRL 11.8–12.0 m, or fixed lengths per order |
| Ends | Beveled ends, plain ends, or threaded and coupled |
| Documentation | EN 10204 Type 3.1 Mill Test Certificate; third-party inspection available |
Size and Schedule Table (ASME B36.10M)
The following table lists common wall thicknesses according to ASME B36.10M. For NPS 12" and above, STD and XS are different designations from SCH 40 and SCH 80, which is a common source of ordering mistakes.
| NPS | OD (mm) | Schedule | Wall Thickness (mm) | Weight (kg/m) |
|---|---|---|---|---|
| 8" | 219.1 | SCH 40 (STD) | 8.18 | 42.55 |
| 10" | 273.1 | SCH 40 (STD) | 9.27 | 60.31 |
| 12" | 323.9 | SCH 80 | 17.48 | 132.08 |
| 16" | 406.4 | SCH 80 | 21.44 | 203.53 |
| 20" | 508.0 | STD / SCH 40 | 9.53 / 15.09 | 117.20 / 183.42 |
| 24" | 609.6 | SCH 80 | 30.96 | 442.08 |
| 36" | 914.4 | Custom | 12.70 – 40.00 | On request |
For NPS 8" and 10", SCH 40 equals STD and SCH 80 equals XS. For NPS 12" and above, these designations are different. Always specify exact wall thickness in millimeters on purchase orders to avoid incorrect supply.
Chemical Composition and Carbon Equivalent
The chemical composition of L360 line pipe is controlled according to the selected PSL level. PSL2 provides stricter chemistry requirements to improve weldability, toughness, and resistance to cracking.
- Maximum carbon equivalent (CEIIW): 0.43%
- Maximum sulfur content: 0.015%
- Maximum phosphorus content: 0.025%
Compared with PSL1, which allows sulfur and phosphorus up to 0.030%, PSL2 provides cleaner steel with improved resistance to hydrogen-induced cracking (HIC).
Mechanical Properties
Both PSL1 and PSL2 have the same minimum yield strength requirement, but PSL2 adds stricter mechanical controls and mandatory testing requirements.
| Property | PSL1 | PSL2 |
|---|---|---|
| Minimum Yield Strength | 360 MPa (52,000 psi) | 360 MPa (52,000 psi) |
| Maximum Yield Strength | Not specified | 530 MPa (77,000 psi) |
| Minimum Tensile Strength | 455 MPa (66,000 psi) | 460 MPa (66,700 psi) |
| Maximum Tensile Strength | Not specified | 760 MPa (110,200 psi) |
| Yield-to-Tensile Ratio | Not required | ≤0.93 (OD >323.9 mm) |
| Charpy V-Notch Impact Test | Not required | Mandatory |
| Carbon Equivalent | Not required | ≤0.43% |
| Hardness | Not specified | ≤250 HV10 (≤248 HV10 for sour service) |
| NDT Inspection | Basic / sampling | 100% full-body UT or RT |
| Repair Welding | Permitted | Prohibited |
| Traceability | Batch-level | Full heat-to-pipe traceability |
PSL2 is available in different delivery conditions:
- X52N: Normalized condition
- X52M: Thermomechanically rolled condition
- X52Q: Quenched and tempered condition
Surface Treatments and Coating Options
Bare carbon steel pipe requires corrosion protection for long-term pipeline service. The coating system depends on operating conditions, environment, and temperature requirements.
- 3LPE Coating: Three-layer polyethylene coating combining FBE primer and HDPE outer protection. Widely used for buried gas pipelines with service temperatures from -40°C to 85°C.
- FBE Coating: Fusion bonded epoxy coating with excellent adhesion and cathodic disbondment resistance. Suitable for offshore and humid environments with temperatures up to approximately 110°C.
- Internal Epoxy Lining: Reduces internal friction, improves flow efficiency, and protects against internal corrosion.
- Black Varnish / Anti-Rust Oil: Temporary protection during storage and transportation.
Quality Testing and Inspection
Every API 5L L360 line pipe undergoes strict inspection before shipment, including:
- 100% hydrostatic testing
- Ultrasonic testing of weld seams and pipe body when required
- Tensile, impact, and hardness testing according to PSL requirements
- Dimensional inspection including OD, wall thickness, length, straightness, and end finish
Third-party inspection services from SGS, BV, DNV, Lloyd's, or customer-appointed agencies are available.
Each shipment includes an EN 10204 Type 3.1 Mill Test Certificate containing heat-specific chemical analysis, mechanical test results, inspection records, and dimensional data.
Verify Before You Pay: We support 3rd-party inspections by SGS, BV, and Lloyd's at our facility. Join 50+ South American energy firms who trust our quality.
Packaging and Shipping
- Small diameter pipes are bundled with steel straps and separated with spacers.
- Large diameter pipes are shipped loose with heavy-duty plastic or metallic end protectors.
- Container shipping is suitable for standard lengths up to 12 meters.
- Breakbulk shipping is available for oversized pipes and large project orders.
Competitive CFR delivery solutions are available to major ports including Santos, Callao, Valparaiso, Buenos Aires, and Cartagena.
FAQ
Is L360 the same as X52?
Yes. L360 and X52 represent the same API 5L grade. L360 indicates minimum yield strength in MPa, while X52 indicates the equivalent value in ksi.
Can L360 pipe be supplied as seamless for high-pressure gas service?
Yes. Seamless L360 is available for smaller diameters and high-pressure applications. ERW and LSAW are commonly used for larger diameter pipelines.
What is the difference between PSL1 and PSL2 for L360?
PSL2 provides stricter chemical control, mandatory impact testing, carbon equivalent limits, maximum strength control, full traceability, and 100% non-destructive testing.
Do you provide mill test certificates?
Yes. EN 10204 Type 3.1 MTC is supplied with every shipment. Type 3.2 inspection with third-party witness is available upon request.
What is the difference between STD, XS, SCH 40, and SCH 80?
For NPS 10" and below, SCH 40 equals STD and SCH 80 equals XS. For NPS 12" and above, these are separate wall thickness designations. Always specify wall thickness in millimeters.
Which production form should I choose?
Seamless pipe is suitable for smaller diameters and high-pressure service. ERW provides an economical solution for medium diameters, while LSAW is preferred for large diameter and thick-wall pipelines.
Procurement Checklist
- Grade: L360 / X52
- PSL level: PSL1 or PSL2
- Delivery condition: N, M, or Q
- Production form: Seamless, ERW, or LSAW
- Dimensions: OD, wall thickness, schedule, and length
- End finish: BE, PE, or threaded and coupled
- Impact test temperature (PSL2)
- Coating requirements
- Quantity and destination port
- Additional requirements: sour service, DWTT, third-party inspection
References
- API Specification 5L - Specification for Line Pipe
- GB/T 9711 - Steel Pipe for Pipeline Transportation Systems
- ASME B36.10M - Welded and Seamless Wrought Steel Pipe
- ISO 3183 - Petroleum and Natural Gas Industries - Steel Pipe for Pipeline Transportation Systems
- EN 10204 - Metallic Products: Types of Inspection Documents
- NACE MR0175 / ISO 15156 - Materials for H₂S-containing Environments
Request a Quotation
Send your complete API 5L L360 (X52) pipe specification to our engineering team. We will confirm availability, technical requirements, pricing, and delivery schedule within 24 hours.
For international pipeline projects, GNEE Pipe provides competitive CFR solutions to major ports worldwide.
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