1. Basic definitions
API 5L: Pipeline steel pipe specification developed by the American Petroleum Institute (API), applicable to oil, natural gas, and other fluid transport pipelines.
X60: Steel grade designation, indicating a minimum yield strength of 60 ksi (approximately 414 MPa).
PSL2: Product specification grade 2, compared to PSL1, the chemical composition, mechanical properties, and testing requirements are more stringent.
2. Chemical Composition
Base element: Based on low-carbon steel, containing carbon (C), manganese (Mn), silicon (Si), and other elements.
Alloying elements: Alloys such as chromium (Cr), molybdenum (Mo), and nickel (Ni) may be added to enhance corrosion resistance and strength.
Acid resistance: X60 PSL2 material (e.g., 'NS' or 'QS' suffix) in accordance with NACE MR0175 for use in corrosive environments, such as those containing hydrogen sulfide.
3. Mechanical properties
| Performance indicators | request(PSL2) | note |
|---|---|---|
| yield strength | ≥414 MPa(X60) | Need to be verified by tensile test |
| tensile strength | ≥517 MPa | Above PSL1 standard |
| impact toughness | Need to meet the Charpy impact test requirements | Stable performance in low temperature environment |
| elongation | ≥18%(Adjusted for pipe diameter and wall thickness) | Ensure pipe plastic deformation capacity |
4. Applications
Oil and gas transmission:
Used in long-distance oil and gas transmission pipelines, especially in high-pressure, highly corrosive media.
Suitable for offshore oil and gas platforms and other harsh environments.
Industrial pipelines:
Acid-resistant materials (such as X60N) can be used for sulfur-containing oil and gas fields, chemical plants, and corrosive media transport.
5. Manufacturing and Testing
Process requirements: Need to be manufactured by double-sided submerged arc welding (such as large-diameter pipe) or seamless pipe process, and the implementation of normalising ('N' suffix) or tempering treatment ('Q' suffix) Testing standard: Normalised ('N' suffix) or tempered ('Q' suffix).
Testing standards: :
Hydrostatic pressure test, ultrasonic flaw detection, X-ray inspection, etc.
Surface 3LPE anti-corrosion coating is optional to enhance durability
