GB/T 9711-2011 PSL2 L290 SSAW Pipe
GB/T 9711-2011 PSL2 L290 SSAW Pipe: High-Strength Pipeline Steel for Oil & Gas Transmission
Comprehensive material data for L290 PSL2 steel used in spiral submerged arc welded pipes, including chemical composition, mechanical properties, and international equivalents.
Thermo-mechanical controlled rolling (TMCP) or normalizing, spiral forming, submerged arc welding, mechanical expansion, hydrostatic testing
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GB/T 9711-2011 PSL2 L290 SSAW Pipe Introduction
L290 is a low-carbon microalloyed steel grade specified in GB/T 9711-2011 for petroleum and natural gas pipeline transmission systems. It belongs to PSL2 (Product Specification Level 2), which imposes stricter requirements on chemical composition, tensile properties, toughness, and non-destructive testing. The steel is typically supplied as hot-rolled strip or plate and fabricated into spiral submerged arc welded (SSAW) pipes. L290 exhibits a minimum yield strength of 290 MPa and excellent weldability, low-temperature toughness, and resistance to hydrogen-induced cracking, making it suitable for high-pressure oil and gas conduits. Its controlled rolling and optional normalizing process ensure fine grain structure and consistent properties across the pipe body.
GB/T 9711-2011 PSL2 L290 SSAW Pipe Chemical Composition
Chemical requirements per GB/T 9711-2011 for PSL2 L290. Values are maximum unless a range is specified. Microalloying elements (Nb, V, Ti) are added individually or in combination to achieve strength and toughness.
- Low sulfur and phosphorus limits ensure resistance to brittle fracture and hydrogen-induced cracking (HIC).
- Carbon equivalent (CE) is typically controlled to ≤0.43% for good weldability.
| Element | Standard Value (wt%) | Remarks |
|---|---|---|
| C | 0.22 max | PSL2 requirements |
| Si | 0.45 max | |
| Mn | 1.20 max | |
| P | 0.025 max | |
| S | 0.015 max | Low sulfur for HIC resistance |
| V | 0.06 max | |
| Nb | 0.06 max | |
| Ti | 0.04 max | |
| V+Nb+Ti | 0.15 max | Sum of microalloying elements |
| Cr | 0.30 max | |
| Ni | 0.30 max | |
| Mo | 0.15 max | |
| Cu | 0.50 max | |
| N | 0.012 max | |
| Al | 0.015 - 0.06 | If added as grain refiner |
| CE (IIW) | 0.43 max | Typical limit for L290 PSL2 |
GB/T 9711-2011 PSL2 L290 SSAW Pipe Thermal and Electrical Physical Properties
Typical physical properties for low-carbon microalloyed pipeline steel (density, elastic moduli, thermal expansion, thermal conductivity, specific heat capacity, and electrical resistivity). Values are representative of L290 steel at room temperature unless otherwise noted.
- These properties are not mandatory in GB/T 9711-2011 but are essential for design and welding simulations.
| Property | Typical Value | Unit | Remarks |
|---|---|---|---|
| Density (ρ) | 7850 | kg/m³ | 20°C |
| Elastic modulus (E) | 207 | GPa | 20°C |
| Shear modulus (G) | 80 | GPa | 20°C |
| Poisson's ratio (ν) | 0.30 | - | Elastic region |
| Thermal expansion coefficient (α) | 11.7 | 10⁻⁶/K | 20–100 °C |
| Thermal conductivity (λ) | 50 | W/(m·K) | 20°C |
| Specific heat capacity | 480 | J/(kg·K) | 20°C |
| Electrical resistivity (ρ_e) | 0.18 | 10⁻⁶ Ω·m | 20°C |
GB/T 9711-2011 PSL2 L290 SSAW Pipe Mechanical Properties
Mechanical properties of L290 PSL2 SSAW pipe base metal according to GB/T 9711-2011. Tests are performed on transverse strip specimens taken from the pipe body, unless otherwise stated. Requirements for PSL2 include a maximum yield-to-tensile ratio and minimum elongation that depends on cross-sectional area.
- Impact tests are mandatory for PSL2 at temperatures as low as -10°C or lower as per purchase agreement.
- Bend test requires no cracks after 180° bending.
| Property | Standard Requirement | Unit | Test Condition |
|---|---|---|---|
| Yield strength (Rt0.5) | 290 - 495 | MPa | Transverse, base metal |
| Tensile strength (Rm) | 415 - 655 | MPa | Transverse, base metal |
| Yield-to-tensile ratio (Rt0.5/Rm) | ≤0.93 | - | PSL2 requirement |
| Elongation after fracture (A) | ≥21 (typical for 12.7 mm wall) | % | Transverse, 50 mm gauge length |
| Bend test (180° bend) | No cracks, bend diameter = 4t | - | Transverse strip, wall thickness ≤25 mm |
| Charpy impact energy (KV2) | ≥40 (average), ≥30 (individual) | J | -10°C, full-size (10x10 mm), transverse |
| Charpy impact energy (KV2) | ≥27 (average), ≥21 (individual) | J | -10°C, 3/4-size (7.5x10 mm), transverse |
| Hardness | ≤220 HV10 or ≤22 HRC | - | PSL2, base metal and weld zone |
GB/T 9711-2011 PSL2 L290 SSAW Pipe Fully Equivalent Material Standards and Replaceable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| International | ISO 3183:2012 | L290 PSL2 | Identical technical content |
| USA | API Spec 5L 45th Ed. | L290/X42 PSL2 | Identical level; SSAW pipe allowed |
| Europe | EN 10208-2:2009 | L290MB | PSL2 equivalent |
| Russia | GOST R 52079-2003 | K42 | Approximate PSL2 equivalence |
| Canada | CSA Z245.1-07 | Grade 290 Cat II | Similar metric strength |
GB/T 9711-2011 PSL2 L290 SSAW Pipe Application Introduction
L290 PSL2 SSAW pipe is primarily used for long-distance oil, gas, and water transmission pipelines where reliable mechanical properties and resistance to fracture and internal pressure are critical. Its excellent weldability and low-temperature toughness enable field construction and operation in harsh environments. SSAW pipes are available in large diameters (up to 2540 mm) and wall thicknesses (up to 25.4 mm), making them suitable for high-volume transmission lines.
Product Applications: Cross-country oil transportation pipelines, High-pressure natural gas trunklines, Submarine pipelines for offshore oil fields, Pipe-in-pipe systems for subsea insulation, Station piping in compressor and pump stations, Water injection and disposal lines
Processed into products: Induction bends and hot-induction elbows (from same material), Pipe fittings (tees, reducers, caps) tailored to L290 strength, Flanges and slip-on weld necks, Prefabricated spools for plant piping, Line pipe risers and tie-in spools
Application industries: Oil and gas exploration and production, Natural gas distribution utilities, Petrochemical and refinery plants, Water supply and sewage treatment, Construction and civil engineering (piling, structural pipes), Offshore and subsea pipelines
GB/T 9711-2011 PSL2 L290 SSAW Pipe Similar or Alternative Steel Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| China | GB/T 9711-2011 | L245 PSL2 | Lower strength (245 MPa min), otherwise similar requirements |
| China | GB/T 9711-2011 | L320 PSL2 | Next higher strength grade (320 MPa min), may require slightly higher carbon equivalent |
| USA | API 5L | X46 PSL2 (L320) | Higher strength, similar toughness; adjust welding procedures |
| USA | API 5L | X52 PSL2 (L360) | Significantly higher strength; check weldability and material compatibility |
Notes:
Additional requirements for PSL2 L290 SSAW pipe:
- Non-destructive testing (NDT) of the weld seam is mandatory (ultrasonic or X-ray).
- Hydrostatic test at 95% specified minimum yield strength (SMYS) or higher.
- Optional testing for hydrogen-induced cracking (HIC) and sulfide stress corrosion cracking (SSCC) for sour service.
- For low-temperature applications, drop-weight tear test (DWTT) to confirm ductile fracture transition temperature may be required.
- The steel may be ordered with supplementary requirements for fine grain practice and inclusion shape control.
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