API 5L X70 vs API 5L X65
These two grades are listed as equivalents of each other: their chemistry windows overlap and they serve the same applications. They are not always identical — check the differences below before substituting, especially in certified designs.
API 5L X70
Pipe & Tube Steel
API 5L X70 is the workhorse grade of modern high-pressure, large-diameter gas pipelines — most new trunk lines are designed in X70. Strength comes from TMCP and microalloying at carbon levels low enough for mechanized field welding.
Standards: DIN L485 (near) · AISI API 5L X70 (PSL2) · GB L485 (GB/T 9711)
API 5L X65
Pipe & Tube Steel
API 5L X65 is the mainstream high-grade line pipe for modern gas transmission, including many of the large-diameter Chinese and transcontinental projects. It offers X70-class economics in milder designs with easier welding than the highest grades.
Standards: DIN L450 (near) · AISI API 5L X65 (PSL2) · GB L450 (GB/T 9711)
Chemical composition compared (%)
| Element | API 5L X70 | API 5L X65 |
|---|---|---|
| C | ≤0.24 (PSL2) | ≤0.24 (PSL2) |
| Si | ≤0.45 | ≤0.45 |
| Mn | ≤1.85 (PSL2) | ≤1.65 (PSL2) |
| P | ≤0.025 | ≤0.025 |
| S | ≤0.015 | ≤0.015 |
Properties compared
| Property | API 5L X70 | API 5L X65 |
|---|---|---|
| Yield strength | ≥485 MPa (70,000 psi) | ≥450 MPa (65,000 psi) |
| Tensile strength | 570–760 MPa (PSL2) | 535–760 MPa (PSL2) |
| Density | 7.85 g/cm³ | 7.85 g/cm³ |
Sourcing either grade?
Nasteel stocks both families from Shenzhen with EN 10204 3.1 mill certificates by heat number.
Ask for a quotationSee full data sheets: API 5L X70 · API 5L X65. Substitution decisions for certified parts stay with the design authority.