API 5L X46 line pipe is the workhorse grade for gathering lines, low-to-medium pressure transmission, and distribution networks where operating pressure exceeds X42 limits but does not require the higher strength of X52. Supplied under PSL1 or PSL2, X46 is widely used for oil, gas, water, and slurry service. This page covers chemistry, mechanical properties, dimensions, and mill direct sourcing from Huaxia-Steel.
Product Overview
API 5L is the American Petroleum Institute specification for line pipe used in pipeline transportation systems. The “X” grade designation (X42, X46, X52, X56, X60, X65, X70, X80) refers to the minimum yield strength in ksi — so X46 has a specified minimum yield strength of 46,000 psi (317 MPa). X46 sits between the commodity X42 and the higher-strength X52, offering a balance of cost and pressure capability.
PSL1 covers the basic line-pipe requirements (chemical composition, tensile properties, hydrostatic test). PSL2 adds mandatory chemical limits on carbon equivalent, mandatory impact testing at low temperature, and traceability to heat number. For most international projects, PSL2 is required.
Available Manufacturing Process
- Seamless (SMLS) — hot-finished or cold-drawn; for high-pressure and sour-service applications. Limited to NPS 26 maximum.
- Electric Resistance Welded (ERW) — for NPS 2 to NPS 24; cost-effective for distribution and gathering.
- Longitudinal Submerged Arc Welded (LSAW) — for large diameter NPS 20 and above; preferred for transmission lines.
- Helical / Spiral Submerged Arc Welded (HSAW / SSAW) — for NPS 20 to NPS 100; competitive pricing on large diameter piling and line-pipe.
Chemical Composition (PSL2, Heat Analysis)
| Element | Maximum % (PSL2, ≤ NPS 25) | Notes |
|---|---|---|
| Carbon (C) | 0.28 | Lower for sour service |
| Manganese (Mn) | 1.40 | — |
| Phosphorus (P) | 0.030 | PSL2 limit |
| Sulfur (S) | 0.030 | PSL2 limit |
| Silicon (Si) | — | — |
| Vanadium (V) | 0.06 | For Nb+V ≤ 0.15 |
| Niobium (Nb) | 0.05 | — |
| Titanium (Ti) | 0.04 | — |
| Carbon Equivalent (CE) | 0.43 max (PSL2 ≤ 42 in) | CE = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15 |
For sour service (NACE MR0175 / ISO 15156), carbon content is limited to ≤ 0.28% and hardness to ≤ 22 HRC. Specify “Sour Service” or “SSC resistant” at order placement.
Mechanical Properties
| Property | Requirement (PSL2) |
|---|---|
| Yield Strength Rp0.2 | 317–524 MPa (46–76 ksi) |
| Tensile Strength Rm | ≥ 434 MPa (63 ksi) |
| Y/T Ratio (max) | 0.93 |
| Elongation in 2 in. | ≥ 22% |
| Charpy Impact (0 °C, full-size) | ≥ 27 J (longitudinal) / ≥ 21 J (transverse) |
| Hardness (for sour service) | ≤ 22 HRC |
Standard Dimensions and Unit Weight
Huaxia-Steel supplies API 5L X46 in standard schedule weights (Sch 20, Sch 40, Sch 80, STD, XS, XXS) plus custom wall thicknesses per project spec.
| NPS (in) | OD (mm) | Sch 40 Wall (mm) | Sch 40 Weight (kg/m) | Sch 80 Wall (mm) | Sch 80 Weight (kg/m) |
|---|---|---|---|---|---|
| 2 | 60.3 | 3.91 | 5.44 | 5.54 | 7.48 |
| 3 | 88.9 | 5.49 | 11.29 | 7.62 | 15.27 |
| 4 | 114.3 | 6.02 | 16.07 | 8.56 | 22.32 |
| 6 | 168.3 | 7.11 | 28.26 | 10.97 | 42.67 |
| 8 | 219.1 | 8.18 | 42.55 | 12.70 | 64.64 |
| 10 | 273.1 | 9.27 | 60.31 | 15.09 | 96.01 |
| 12 | 323.9 | 10.31 | 79.73 | 17.48 | 132.05 |
| 16 | 406.4 | 12.70 | 123.30 | 21.44 | 203.54 |
| 20 | 508.0 | 15.09 | 183.43 | 26.19 | 311.19 |
| 24 | 609.6 | 17.48 | 255.27 | 30.96 | 442.11 |
Custom sizes up to NPS 48 available in LSAW. Tolerance per API 5L: OD ±0.75% (seamless) or ±1.0% (welded); wall thickness -12.5% (no positive tolerance for seamless, +20% for welded).
Manufacturing Standards
- API 5L (45th / 46th edition) — product specification.
- ISO 3183 — international equivalent (predominantly PSL2 alignment).
- ASME B36.10M — dimensional standard for steel pipe.
- ASTM A53 / A106 — for non-API applications where line-pipe certification is not required.
- NACE MR0175 / ISO 15156 — for sour-service (H₂S) environments.
Typical Applications
- Oil and gas gathering lines (wellhead to processing facility).
- Low-to-medium pressure gas distribution networks.
- Water injection and disposal lines.
- Slurry transport in mining operations.
- Firewater and utility piping in refineries.
- Offshore platform intra-field flowlines (PSL2 mandatory).
- Compressor station suction and discharge piping.
Quality Assurance and Testing
Every heat of X46 line pipe from Huaxia-Steel comes with the following mandatory tests:
- Chemical analysis (heat and product) per ASTM A415.
- Tensile test — yield, ultimate, elongation, Y/T ratio.
- Charpy V-notch impact — 3 specimens at specified temperature (typically 0 °C or -20 °C).
- Hydrostatic test — pressure per API 5L formula, hold minimum 5 seconds.
- Dimensional inspection — OD, wall, length, ovality, straightness.
- Visual inspection — surface defects, weld bead, marking.
- Non-destructive testing — ultrasonic on weld seam (100%), radiographic spot-check, MPI on pipe ends.
Mill test certificate per EN 10204-3.1 or API 5L Annex E. Optional third-party inspection by SGS / BV / TUV / Intertek available at extra cost.
Marking and Traceability
Each pipe is stenciled at both ends with the following information per API 5L:
- Manufacturer name or mark
- API 5L designation (e.g., “5L X46 PSL2”)
- Manufacturing process (SMLS / ERW / LSAW / SSAW)
- Heat number
- Size (NPS and OD)
- Wall thickness (or schedule)
- Length (random, exact, or multiple)
- Weight per unit length
- Standard reference year (e.g., “API 5L 46th”)
Color coding follows project specification or API 5L Annex G. Default: green band for grade X46 if no other spec.
Packaging and Shipping
- Standard export packing: Hexagonal bundle with steel strips, plastic end caps, woven-bag wrapping for Sch 40 and lighter. Hexagonal bundles fit 40-foot HQ containers efficiently.
- Bulk vessel: For large orders (5,000+ tonnes), pipes are loaded directly into bulk carriers for FOB or CFR terms.
- Loose in container: For large-diameter (NPS 16+) LSAW pipe that exceeds bundle practicality.
- Bevelled ends: Standard 30° ±5° bevel per ASME B16.25. Square-cut ends available on request.
- Plastic pipe caps: Fitted to all pipe ends to prevent contamination during transit.
Order API 5L X46 Line Pipe from Huaxia-Steel
Huaxia-Steel supplies API 5L X46 PSL1 and PSL2 line pipe from certified Chinese mills with monthly capacity exceeding 30,000 tonnes. We offer SMLS, ERW, LSAW, and SSAW in all standard schedules from NPS 2 to NPS 48, with optional third-party inspection, sour-service compliance, and custom end preparation. Send your project specification to [email protected] for a mill-direct quote within 24 hours.
Related products: API 5L X42 Line Pipe · API 5L X52 Line Pipe · API 5L X60 Line Pipe
