API 5L X70
Data verifiedAPI 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.
Chemical composition
| Element | Content (%) |
|---|---|
| C | ≤0.24 (PSL2) |
| Si | ≤0.45 |
| Mn | ≤1.85 (PSL2) |
| P | ≤0.025 |
| S | ≤0.015 |
Weight percent, per the governing standard ranges. Actual values per heat are on the mill certificate.
Properties
| Yield strength | ≥485 MPa (70,000 psi) |
| Tensile strength | 570–760 MPa (PSL2) |
| Density | 7.85 g/cm³ |
Heat treatment
TMCP with accelerated cooling; DWTT shear-area requirements apply for gas service.
Equivalent grades
| Standard | Designation |
|---|---|
| din | L485 (near) |
| aisi | API 5L X70 (PSL2) |
| gb | L485 (GB/T 9711) |
Compare side by side: API 5L X70 vs API 5L X65 · API 5L X70 vs API 5L X80
Equivalents overlap in chemistry and use but are not always identical — see our equivalents guide before substituting in certified designs.
Applications & Processing
Applications: Long-distance gas pipelines, large-diameter trunk lines, Arctic pipelines (with low-temp toughness options).
Processing: Mechanized GMAW field welding is standard; PSL2 caps on CE/Pcm keep preheat low.
FAQ
- Why is X70 more common than X80?
- X70 hits the best balance of design pressure, wall thickness, mill availability and field weldability; X80 saves more steel but fewer mills and contractors support it.
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Ask for a quotationVisit NasteelSource: API 5L published ranges · Last updated 2026-11-03. Data is indicative — verify critical values against the governing standard and mill certificate before use.