API 5L X65 and X70 are high-strength steels under the API 5L standard. X70 has a minimum yield strength of 485 MPa (approximately 70,000 psi), while X65 has 448 MPa (approximately 65,000 psi), making X70 approximately 8.2% stronger. With the same wall thickness, X70 can withstand higher internal pressures, or its material and transportation costs can be reduced through thinner designs.
Stuck choosing between X65 and X70? Get a free 1-on-1 consultation with our 10-year pipeline engineer to calculate how 10% thinner walls can cut costs!
Mechanical Properties Comparison
| Property | API 5L X65 (L450) | API 5L X70 (L485) | Procurement Insights |
| Yield Strength (min) | 450 MPa (65,300 psi) | 485 MPa (70,300 psi) | X70 is ~8% stronger than X65. |
| Tensile Strength (min) | 535 MPa (77,600 psi) | 570 MPa (82,700 psi) | Determines the ultimate pressure limit. |
| Yield-to-Tensile Ratio | ≤ 0.93 (PSL2) | ≤ 0.93 (PSL2) | Measures the plastic deformation limit. |
| Elongation (min %) | Based on cross-sectional area | Based on cross-sectional area | High ductility is required for both. |
| CVN Impact Energy | Per project spec/Standard | Per project spec/Standard | X70 often requires stricter low-temp tests. |
Chemical Composition Comparison (PSL2)
| Element (Max %) | X65 (PSL2) | X70 (PSL2) | Procurement Focus |
| C (Carbon) | 0.12 | 0.12 | Low carbon ensures better weldability. |
| Mn (Manganese) | 1.60 | 1.70 | X70 uses higher Mn to increase strength. |
| Si (Silicon) | 0.45 | 0.45 | Used as a deoxidizer. |
| P (Phosphorus) | 0.025 | 0.025 | Impurity; lower is better for toughness. |
| S (Sulphur) | 0.015 | 0.015 | Critical for HIC/Sour service resistance. |
| Nb + V + Ti | ≤ 0.15 | ≤ 0.15 | Micro-alloying elements for grain refinement. |
| CEq (Carbon Equiv.) | ≤ 0.43 | ≤ 0.43 | Key Metric for field welding difficulty. |
Manufacturing & Testing Requirements
| Feature | API 5L X65 | API 5L X70 | Buying Recommendation |
| Pipe Type | SMLS, HFW, LSAW, SSAW | Mainly LSAW, HFW, SMLS | LSAW is common for large diameter X70. |
| Delivery Condition | N (Norm.), M (TMCP), Q (Q+T) | Mainly M (TMCP) | TMCP is the industry standard for X70. |
| NDT (Non-Destructive) | 100% RT / UT (for PSL2) | 100% RT / UT (for PSL2) | Mandatory for high-pressure lines. |
| Hydrostatic Test | Required | Required | Test pressure depends on Wall Thickness. |
| Sour Service (H2S) | Highly Mature Tech | Requires special processing | X65 is often the "safe" choice for Sour Service. |
API 5L X65 X70 oil and gas pipelines Size Specifications
| Nominal Size (in) | Outside Diameter (mm) | X65 Wall Thickness (mm) | X70 Wall Thickness (mm) | Weight Range (kg/m) | Typical Applications |
|---|---|---|---|---|---|
| 6 | 168.3 | 8.2 | 8.2 | 32.5 | Urban gas mainlines |
| 10 | 273.1 | 10.3 | 10.3 | 67.8 | Medium-pressure gathering lines |
| 16 | 406.4 | 12.7 | 12.7 | 98.5 | National trunk pipelines |
| 20 | 508.0 | 15.9 | 15.9 | 152.0 | High-pressure long-distance lines |
| 24 | 610.0 | 19.1 | 19.1 | 220.0 | Inter-regional transmission |
| 30 | 762.0 | 22.2 | 22.2 | 315.0 | Deepwater/high-pressure mainlines |
| 36 | 914.4 | 25.4 | 25.4 | 440.0 | Ultra-large diameter energy corridors |
GNEE API 5L X65 X70 Carbon Steel Line Pipe Factory
FAQ
What is API 5L X70 material?
API 5L X70 steel pipe has a minimum yield strength of 70,300 psi or 485 Mpa. The current X70 steel pipe are all controlled micro-alloyed carbon-manganese steels. The micro-alloys elements are mainly Nb, V and Ti, and the total content of micro-alloys does not exceed 0.15%.
What is API 5L grade X65 material?
API 5L X65 PSL2 Pipe, API 5L X65 carbon steel or L450 X65 Pipe is an alloy of elements like manganese, phosphorus, sulphur and titanium. The API 5L X65 chemical composition of these pipes make it one of the most valued and versatile pipes ever.
What is the thermal conductivity of API 5L X65?
Moreover, it demonstrates a thermal conductivity between 29-33 W/(m•K), ensuring efficient heat transfer in various applications. API 5L Carbon Steel X65 Pipe offers exceptional machining and welding properties, facilitating easy fabrication and assembly in various applications.