GB/T 9711-2011 PSL1 L320 Spiral Welded Line Pipe
GB/T 9711-2011 PSL1 L320 Spiral Welded Line Pipe Material Data & Equivalent Grades
Comprehensive material analysis of L320 PSL1 spiral submerged arc welded (SSAW) pipe according to GB/T 9711-2011, covering chemical composition, mechanical properties, thermal-electrical performance and international equivalents.
Hot-rolled skelp forming, submerged arc welding (inside and outside), edge milling, hydraulic expansion (optional), ultrasonic/hydrostatic testing, cutting and end finishing.
- Phone : +8618037372205
- Email : [email protected]
- WhatsApp: Contact via Whtsapp
- WeChat: +8618037372205
GB/T 9711-2011 PSL1 L320 Spiral Welded Line Pipe Introduction
L320 is a line pipe steel grade specified in China standard GB/T 9711-2011, which is technically equivalent to ISO 3183:2007. It is primarily used for spiral submerged arc welded (SSAW) pipes in Product Specification Level 1 (PSL1). The grade designation 'L' indicates line pipe, and the number 320 denotes the minimum specified yield strength of 320 MPa. This steel offers good weldability, sufficient strength and acceptable toughness for the transportation of oil, gas, and water. The PSL1 requirements focus on basic quality with less stringent testing compared to PSL2. Typical delivery condition is as-welded or normalized, and the material is suitable for large-diameter pipelines operating at moderate pressures. The chemical composition limits carbon, manganese, phosphorus and sulfur, with an optional control on carbon equivalent (CEV) to improve field weldability.
GB/T 9711-2011 PSL1 L320 Spiral Welded Line Pipe Chemical Composition
The chemical composition for L320 PSL1 steel complies with the maximum limits in GB/T 9711-2011 Table 4. Carbon equivalent (CEV) is restricted to ensure good field weldability. Microalloying elements such as niobium, vanadium and titanium may be added at the manufacturer's discretion but are not mandatory for PSL1.
| Chemical Element | Standard Value (max %) | Remarks |
|---|---|---|
| Carbon (C) | 0.26 | Heat analysis |
| Manganese (Mn) | 1.40 | Heat analysis |
| Phosphorus (P) | 0.030 | Heat analysis |
| Sulfur (S) | 0.030 | Heat analysis |
| Carbon Equivalent (CEV) | 0.43 | CEV = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15 |
GB/T 9711-2011 PSL1 L320 Spiral Welded Line Pipe Thermal and Electrical Physical Properties
The values below are typical for carbon-manganese line pipe steel and are not part of the delivery requirements of GB/T 9711-2011. They are provided for engineering reference only. Actual values may vary with specific chemical composition and heat treatment condition.
| Property | Typical Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | 20 °C |
| Modulus of Elasticity (E) | 205 | GPa | 20 °C |
| Shear Modulus (G) | 80 | GPa | 20 °C (calculated) |
| Poisson's Ratio (ν) | 0.30 | – | 20 °C |
| Thermal Expansion Coefficient (α) | 12.0 × 10⁻⁶ | /°C | 20 – 100 °C |
| Thermal Conductivity (λ) | 45 | W/(m·K) | 20 °C |
| Specific Heat Capacity | 480 | J/(kg·K) | 20 °C |
| Electrical Resistivity (ρₑ) | 0.20 × 10⁻⁶ | Ω·m | 20 °C |
GB/T 9711-2011 PSL1 L320 Spiral Welded Line Pipe Mechanical Properties
Mechanical testing is performed on transverse or longitudinal specimens, with requirement values identical for both directions. The yield strength is determined at 0.5% total extension (Rt0.5). The elongation is calculated per formula or agreed upon; the bending test uses a guided bend with a 6t mandrel for thickness ≤25.4 mm. No impact test is required for PSL1 unless specified in the purchase order.
| Property | Required Value | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (Rt0.5) | 320 – 525 | MPa | Room temperature, longitudinal or transverse specimen |
| Tensile Strength (Rm) | 435 – 655 | MPa | Room temperature, longitudinal or transverse specimen |
| Elongation (A) | By formula or as agreed | % | Gauge length 50 mm, formula: A = 1940×Axc0.2 / Rm0.9 |
| Guided Bend Test (mandrel diameter) | 6 × t (t ≤ 25.4 mm) | mm | Transverse weld and base metal, 180° bend angle |
GB/T 9711-2011 PSL1 L320 Spiral Welded Line Pipe Exact Equivalent Material Standards and Replaceable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| International | ISO 3183 | L320 | PSL1, welded pipe |
| USA | API 5L | X46 | PSL1, SSAW/FW pipe |
GB/T 9711-2011 PSL1 L320 Spiral Welded Line Pipe Application Introduction
L320 PSL1 SSAW pipe is designed for fluid transportation at moderate pressures in both onshore and offshore environments. Its spiral welded construction allows economical production of large-diameter pipes and easy adjustment of pipe diameter by varying the forming angle. Typical applications include:
- Cross-country oil and gas trunk lines
- Water transmission and distribution networks
- Structural pipe piling for bridges, ports and buildings
- Offshore platform piping and risers (with additional toughness requirements)
Product Applications: Spiral welded steel pipe (SSAW), Line pipe sections, Casing and conductor pipe, Penstock pipes for hydropower plants
Processed into products: Pipe bends (hot/cold formed), Reducers and tee fittings, Anchor flanges and ring stiffeners, Pipe joints and flanges
Application industries: Oil & Gas Transmission, Water Supply & Sewage, Civil Engineering / Construction, Offshore & Marine Infrastructure
GB/T 9711-2011 PSL1 L320 Spiral Welded Line Pipe Similar/Alternative Materials with Close Performance
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| China | GB/T 9711-2011 | L290 | Lower yield strength (290 MPa min), else similar PSL1 properties |
| China | GB/T 9711-2011 | L360 | Higher yield strength (360 MPa min), slightly higher CEV, good compatibility |
Notes:
PSL1 L320 pipes are subject to hydrostatic testing, dimensional checks, and visual/non-destructive testing of the weld as per GB/T 9711-2011. For sour service or low-temperature applications, PSL2 or supplementary requirements are usually specified. Additional chemical restrictions on S and CEV may be agreed. The pipe ends can be supplied plain, bevelled or with special end preparations for field welding.
- Share
