Products Description
API 5L Grade B PSL2 seamless steel pipe is a high-strength carbon steel line pipe manufactured in accordance with API Specification 5L, the American Petroleum Institute's standard for seamless and welded line pipe used in petroleum and natural gas transportation systems. The PSL2 designation indicates a higher quality level with mandatory impact testing, stricter chemistry controls, full pipe body NDT, and carbon equivalent limits compared to PSL1.
This product combines a seamless pipe body with a dual coating system: an external 3-Layer Polyethylene (3LPE) coating for buried service protection, and an internal liquid epoxy lining for flow efficiency and corrosion resistance. The result is a pipeline product engineered for demanding oil, gas, and water transmission applications.
| Item | Details |
|---|---|
| Product Name | API 5L GR.B PSL2 Seamless Steel Line Pipe |
| Standard | API Spec 5L, ISO 3183 |
| Steel Grade | GR.B (L245), PSL2 |
| Manufacturing Process | Hot rolled seamless |
| Outer Diameter | 21.3mm ~ 426mm (custom sizes available) |
| Wall Thickness | Sch20, Sch40, STD, Sch60, Sch80, XS etc. |
| Pipe Length | 5.8m / 6m / 11.8m / 12m or random length |
| Pipe End | Bevelled end for welding; plain end optional |
| External Coating | 3LPE (3-Layer Polyethylene)1st layer: FBE powder epoxy2nd layer: adhesive copolymer3rd layer: polyethylene outer layer |
| Internal Coating | Liquid epoxy coating / FBE epoxy coating, blue coating normally |
| Marking | Permanent marking: API 5L, Grade, PSL2, OD, WT, Heat No., Mill Mark |
| Packaging | Steel bundles with steel straps, end caps to protect coating |
Coating System
1.External Coating: 3-Layer Polyethylene (3LPE)
The 3LPE coating is a factory-applied, multi-layer anti-corrosion system designed for buried pipelines operating at design temperatures from −20°C to +65°C (extended temperature ranges available upon qualification). It consists of three functional layers:
| Layer | Material | Function | Typical Thickness |
| Layer 1 | Fusion-Bonded Epoxy (FBE) | Primary corrosion barrier; bonds to blast-cleaned steel | ≥ 125 μm |
| Layer 2 | Copolymer / Grafted Adhesive | Connects FBE primer to polyethylene topcoat | ≥ 150 μm |
| Layer 3 | Extruded Polyethylene | Mechanical protection against impact, indentation, and abrasion | 1.8 – 4.7 mm |
| Total System | - | Complete qualified coating system | 2.0 – 3.7 mm (typical) |
The 3LPE system shall be specified as a complete qualified coating system-not by total thickness alone. The release basis comprises: base pipe + coating standard + qualified material combination + process controls + inspection records.
Governing standards:
- ISO 21809-1:2018 - Plant-applied external three-layer polyethylene coatings
- DIN 30670-1:2024-01 - Factory-applied extruded polyethylene coatings on steel pipes
- CSA Z245.21:22 - Plant-applied external polyethylene coating requirements
- GB/T 23257 - Buried steel pipeline polyethylene coating (Chinese standard, where applicable)
Surface preparation: Blast cleaning to Sa 2½ (ISO 8501-1) with surface profile of 40–100 μm, assessed by ISO 8503 series comparators.
2.Internal Coating: Liquid Epoxy Lining
The internal epoxy lining is a two-component, solvent-free or high-solids liquid epoxy coating applied by airless spray to the internal surface of the pipe. It provides a smooth, mechanically robust coating that improves flow rates and provides corrosion protection during transportation and intermediate storage.
| Parameter | Specification |
| Coating Type | Two-component liquid epoxy (solvent-free / high-solids) |
| Typical Dry Film Thickness | 75 – 600 μm (project-dependent; 600 μm for potable water per common specifications) |
| Color | Red-brown / Light green (project-dependent) |
| Temperature Resistance | Dry heat up to ~120°C; short-term up to ~300°C |
| Certification Standards | API RP 5L2, ISO 15741, EN 10301 |
The internal lining system is typically specified as a plural-component hot-applied solvent-free epoxy to a thickness of 600 μm for water service, or 75–125 μm for gas flow coating applications.
Governing standards:
- API RP 5L2 - Recommended Practice for Internal Coating of Line Pipe for Non-Corrosive Gas Transmission Service
- ISO 15741:2016 - Liquid epoxy paints and internal coatings for steel pipes for non-corrosive gas conveyance
- EN 10301 - Internal linings for steel pipes and fittings
Technical Parameters
1.Chemical Composition (PSL2, Grade B)
| Element | Max (wt %) | Notes |
| Carbon (C) | 0.22 | 0.24% permitted for seamless product |
| Manganese (Mn) | 1.2 | Mn may increase to 1.65% max with C reduction |
| Phosphorus (P) | 0.025 | |
| Sulfur (S) | 0.015 | |
| Silicon (Si) | 0.45 | |
| Copper (Cu) | 0.5 | |
| Nickel (Ni) | 0.3 | |
| Molybdenum (Mo) | 0.15 | |
| Niobium (Nb) | 0.05 | |
| Vanadium (V) | 0.05 | |
| Titanium (Ti) | 0.04 |
Carbon Equivalent (max):
CE(IIW) = 0.43%
Pcm = 0.25%
Composition meets PSL2 (BM) requirements. For sour service applications, SSC/HIC performance per NACE MR0175/ISO 15156 is available upon inquiry.
2.Mechanical Properties (PSL2, Pipe Body)
| Property | Requirement |
| Yield Strength | 245 MPa (35.5 ksi) min |
| Tensile Strength | 415 MPa (60.2 ksi) min |
| Yield-to-Tensile Ratio | ≤ 0.93 |
| Elongation | Per API 5L Table 7 (minimum varies with specimen size) |
| Impact Test | Mandatory (PSL2); typically −20°C, ≥27 J for Grade B |
| Hardness (sour service) | ≤ 22 HRC / 248 HBW |
| Hydrostatic Test | Mandatory |
PSL2 mandates tighter chemistry controls, mandatory impact testing, full pipe body NDT, and carbon equivalent limits compared to PSL1. The yield-to-tensile ratio must not exceed 0.93, as an excessively high ratio indicates reduced ductility.
Applications
API 5L Grade B PSL2 seamless pipe with 3LPE external coating and epoxy internal lining is specified for:
Oil & Gas Transmission
- Onshore gathering and transmission pipelines
- Offshore platform flowlines (3LPE provides extended maintenance-free service)
- Sour service gas fields (with NACE MR0175 compliant materials)
- Low-pressure oil and gas distribution systems (< 4.0 MPa)
Water & Wastewater
- Potable water transmission mains (with NSF 61-compliant internal lining)
- Sewage and raw water pipelines
- Desalination plant piping
Industrial & Infrastructure
- Petrochemical process piping
- Mineral slurry pipelines
- High-pressure steam transfer in petrochemical facilities
- Structural support and mechanical fluid conveyance
Seamless construction eliminates weld seam weaknesses, providing 15% improved pressure uniformity over welded pipe and enabling service in high-pressure and low-temperature environments
FAQ
Q1: What is the difference between PSL1 and PSL2?
PSL2 imposes stricter quality control and testing requirements: mandatory impact testing, full pipe body NDT (non-destructive testing), tighter chemical composition limits, carbon equivalent restrictions, and enhanced traceability documentation. PSL1 covers basic requirements without these enhanced controls-. For critical applications-especially sour service or low-temperature environments-PSL2 is the standard specification.
Q2: Can the internal coating be substituted with FBE?
Internal FBE coating (fusion-bonded epoxy powder) is an alternative to liquid epoxy lining. However, liquid epoxy flow coating typically provides a smoother surface finish that reduces friction in gas transmission. For potable water service, epoxy powder lining per CJ/T 120 is commonly specified. The choice depends on the conveyed medium and project specifications.
Q3: What is the maximum service temperature for the 3LPE coating?
The standard 3LPE system is qualified for design temperatures from −20°C to +65°C. For higher temperatures, 3-layer polypropylene (3LPP) coating per DIN 30678 or ISO 21809-1 is recommended.
Q4: How are pipe ends protected during shipment?
Pipe ends are typically protected with beveled end protectors or plastic caps. The 3LPE coating is cut back at pipe ends (typical cutback length 100–150 mm) to facilitate field welding, and the cutback area is protected with a compatible field-applied coating or heat-shrink sleeve.
Q5: What testing documentation is provided?
A mill test certificate (MTC) per EN 10204 3.1 is provided, reporting chemical composition, mechanical properties, and test results. For 3LPE coating, inspection records include coating thickness measurements, holiday detection, cathodic disbondment testing, and impact resistance per the governing coating standard.
Q6: Is this product suitable for sour service?
Grade B PSL2 pipe can be supplied with SSC/HIC testing per NACE TM0177 and NACE TM0284 upon request. Hardness is controlled to ≤ 22 HRC / 248 HBW. Carbon equivalent is calculated and reported. Consult the mill for specific sour service qualification.
Our address
Rm1406,14th/F No 208, Hongqi Road, Nankai Dist, Tianjin City ,China
Phone Number(WhatsApp/Wechat)
+8616622033809
alisa@tjshenzhoutong.com
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