L360 (also designated X52) is an API 5L pipeline steel grade where "L" stands for line pipe and "360" refers to the minimum yield strength of 360 MPa - roughly 52 ksi, which is where the X52 name comes from. The grade relies on microalloying with elements like niobium, vanadium, and titanium, combined with controlled rolling and cooling (TMCP), to deliver a solid balance of strength, toughness, and weldability. These properties make it a common choice for oil and gas transmission pipelines.
GNEE Pipe supplies L360 line pipe in seamless, ERW, and LSAW forms, covering PSL1 and PSL2 quality levels to API 5L and GB/T 9711. Every order ships with full MTC documentation (EN 10204 3.1/3.2) and 100% hydrostatic testing.
Specifications
-
Standard: API 5L (latest edition) / GB/T 9711; PSL1 and PSL2 available
Production forms: Seamless (SMLS), ERW, and LSAW
Size range: 21.3 mm – 1524 mm (1/2" – 60") overall
Seamless: OD 1/2" – 24"
ERW: OD 4" – 24"
LSAW: OD 18" – 60"
Wall thickness: SCH 20, STD, SCH 40, SCH 80, SCH 160, XXS, and custom heavy walls (2 mm – 60 mm)
Length: SRL 5.8–6.0 m, DRL 11.8–12.0 m, or fixed lengths up to 18 m
Pipe ends: Beveled (large OD), plain (small OD), or threaded and coupled
Documentation: Full mill test certificate (MTC); third-party inspection available on request
Chemical Composition and Mechanical Properties
The table below lists typical limits; exact values are governed by the PSL level in API 5L / GB/T 9711 and are stated on the mill test certificate for each heat.
| Property | L360 (PSL1) | L360 (PSL2) |
|---|---|---|
| Carbon (C) max, % | 0.28 | 0.24 |
| Manganese (Mn) max, % | 1.40 | 1.40 |
| Phosphorus (P) max, % | 0.030 | 0.025 |
| Sulfur (S) max, % | 0.030 | 0.015 |
| Yield strength (MPa) | 360 min | 360 – 530 (per governing edition) |
| Tensile strength (MPa) | 460 min | 460 – 760 |
Note: The yield and tensile ranges shown for PSL2 follow the applicable API 5L edition. For PSL2 orders, the yield-to-tensile ratio is also capped (typically ≤ 0.93), and carbon equivalent (CEV) limits apply. Always confirm specific values with our engineers when issuing your specification.
Sour Service Considerations
Standard L360 pipe is not automatically qualified for sour service - meaning environments where the fluid contains hydrogen sulfide (H₂S). If your operating conditions are sour, the pipe needs to be ordered to the applicable sour-service requirements. In practice, this means compliance with NACE MR0175 / ISO 15156, including HIC (hydrogen-induced cracking) and SSC (sulfide stress cracking) testing. GNEE Pipe can arrange sour-service qualification - just let us know your service conditions when you inquire, and we'll confirm the grade, PSL, and supplementary requirements before production.
Manufacturing Processes
Seamless (SMLS) - High-Pressure Applications
Seamless pipe is made by heating a solid billet and piercing it to form a hollow tube. With no weld seam, it offers maximum structural integrity and is the preferred choice for high-pressure gas lines and critical refinery infrastructure. Available in OD 1/2" – 24".
ERW (Electric Resistance Welded) - Mid-Range Pipelines
ERW pipe is formed from steel plate and welded using high-frequency electric resistance. It's a cost-effective option for long-distance onshore pipelines in the 4" – 24" diameter range, offering a smooth finish and reliable performance.
LSAW (Longitudinal Submerged Arc Welded) - Large-Diameter Lines
LSAW pipe is produced by welding steel plate longitudinally using submerged arc welding. It's used for large-diameter applications (18" – 60"), typically in water transmission, low-pressure oil lines, and major infrastructure projects.
Quality Testing & Inspection
Every pipe goes through a rigorous testing program to meet API 5L requirements:
100% hydrostatic testing on every joint
Charpy V-notch impact testing - mandatory for PSL2, at the temperature specified in your order
Ultrasonic testing of the weld seam (welded forms) and, where specified, the base material
Third-party inspection by your nominated agency, fully supported at our facility
Packaging & Shipping
Container Loading (20ft / 40ft GP)
Best for small to medium orders (under 500 tons) and pipe lengths of 5.8 m or 11.8 m. Containers offer the best protection from the elements, with fixed schedules from major carriers like Maersk, MSC, and COSCO. We use specialized V-shape timber cradles to keep pipes from shifting in transit.
Breakbulk (Bulk Vessel)
For large-diameter pipes (over 20") or high-volume orders (1,000+ tons), breakbulk shipping typically costs less per ton than containers for oversized cargo. Make sure the vessel has under-deck stowage to avoid direct seawater exposure during transit.
Special Equipment (Flat Rack / Open Top)
Used for extremely heavy-wall L360 pipe that standard container forklifts can't handle.
API 5L Line pipe MTC
FAQ
What's the difference between L360 and X52?
They're the same grade. L360 expresses the minimum yield strength in MPa (360 MPa), while X52 uses ksi (52 ksi). Both designations appear in API 5L documentation and refer to identical material requirements.
Can L360 pipe be used in sour gas service?
Only when ordered and tested to sour-service requirements - specifically NACE MR0175 / ISO 15156 with HIC and SSC testing. Standard L360 off the shelf is not suitable for H₂S-containing environments.
What production forms are available?
Seamless pipe up to 24" OD, ERW from 4"–24", and LSAW from 18"–60". Talk to our engineers to confirm the best form and size for your project.
Do you provide full documentation?
Yes. Every shipment comes with a full mill test certificate. EN 10204 Type 3.1 is standard, and Type 3.2 (with third-party witness) can be arranged on request.
What's the difference between PSL1 and PSL2?
PSL2 has stricter requirements than PSL1 - lower carbon, phosphorus, and sulfur limits, mandatory impact testing, defined strength ranges (not just minimums), and a yield-to-tensile ratio cap. PSL2 is typically required for more critical or regulated pipeline applications.
References
- API Specification 5L - Specification for Line Pipe (PSL1 / PSL2).
- GB/T 9711 - Petroleum and natural gas industries: Steel pipe for pipeline transportation systems.
- NACE MR0175 / ISO 15156 - Petroleum and natural gas industries: Materials for use in H₂S-containing environments in oil and gas production.
- ASME B36.10M - Welded and Seamless Wrought Steel Pipe (dimension basis).
- EN 10204 - Metallic products: Types of inspection documents.
Request a Quotation
Send your grade (L360 / X52), PSL level, production form, size, wall thickness, service conditions and quantity to sales@gneetube.com or use the Inquiry form. Our engineers will confirm specifications and delivery within 24 hours.
Hot Tags: api l360 carbon steel line pipe, China api l360 carbon steel line pipe manufacturers, suppliers, factory, api 5l seamless steel pipe grade, steel tubing api 5l seamless price, tubing api 5l seamless manufacturers, seamless steel pipe api 5l alloy, steel tubing api 5l seamless alloy, seamless steel pipe api 5l cost
