API 5L X42 ERW Pipe
Basic Overview
API 5L X42 ERW (Electric Resistance Welded) pipe is a medium-strength carbon steel line pipe used in oil and gas transmission systems. The "X42" designation indicates a minimum yield strength of 42,000 psi (290 MPa) , positioning it as a step above Grade B for applications requiring higher pressure capacity without moving to higher-strength grades [citation:3, citation:6].
Name Explanation
| Part | Meaning |
|---|---|
| API | American Petroleum Institute |
| 5L | Specification for line pipe used in pipeline transportation systems |
| X42 | Grade designation – "X" indicates pipeline grade, "42" represents minimum yield strength in ksi (42,000 psi / 290 MPa) |
| ERW | Electric Resistance Welded – pipe formed from steel coil and welded longitudinally without filler metal |
Key Features
| Feature | Description |
|---|---|
| Yield Strength (min) | 290 MPa (42,000 psi) [citation:3, citation:6] |
| Tensile Strength (min) | 415 MPa (60,000 psi) [citation:3, citation:6] |
| Manufacturing | Electric Resistance Welded (ERW) – high-frequency welding process |
| Size Range | 21.3 mm to 660 mm (1/2" to 26") OD [citation:2, citation:6] |
| Wall Thickness | 1.8 mm to 25.4 mm (Schedule 10 to 160, STD, XS) [citation:2, citation:5] |
| Length | 3 m to 18 m (customizable) [citation:2, citation:6] |
| Product Specification Levels | PSL1 (standard) and PSL2 (enhanced) |
Chemical Composition (PSL1, max %)
| Element | Specification | Notes |
|---|---|---|
| Carbon (C) | 0.26% max | Lower than Grade B for better weldability |
| Manganese (Mn) | 1.30% max | Provides strength |
| Silicon (Si) | 0.40% max | Deoxidizer |
| Phosphorus (P) | 0.030% max | Tightly controlled |
| Sulfur (S) | 0.030% max | Controlled for toughness |
Note: PSL2 grades have tighter limits (C ≤ 0.22%, S ≤ 0.015%, P ≤ 0.025%) and require mandatory impact testing .
Mechanical Properties
| Property | PSL1 Requirement | PSL2 Requirement |
|---|---|---|
| Yield Strength (min) | 290 MPa (42,000 psi) [citation:3, citation:6] | 290 MPa (42,000 psi) |
| Yield Strength (max) | Not specified | 496 MPa (72,000 psi) |
| Tensile Strength (min) | 415 MPa (60,000 psi) [citation:3, citation:6] | 415 MPa (60,000 psi) |
| Tensile Strength (max) | Not specified | 758 MPa (110,000 psi) |
| Yield-to-Tensile Ratio | Not specified | 0.93 max |
| Elongation | ≥ 21-28% (varies by wall thickness) | ≥ 21% |
Grade Comparison
| Grade | Yield Strength (min) | Tensile Strength (min) | Relative Strength vs. X42 | Typical Application |
|---|---|---|---|---|
| A | 207 MPa (30 ksi) | 331 MPa (48 ksi) | -29% | Low-pressure gathering |
| B | 241 MPa (35 ksi) | 414 MPa (60 ksi) | -17% | General pipeline service |
| X42 | 290 MPa (42 ksi) | 415 MPa (60 ksi) | Baseline | Medium-pressure transmission |
| X46 | 320 MPa (46 ksi) | 435 MPa (63 ksi) | +10% | Higher-pressure transmission |
| X52 | 359 MPa (52 ksi) | 455 MPa (66 ksi) | +24% | General transmission |
Dimensional Tolerances
| Parameter | Tolerance | Source |
|---|---|---|
| Outside Diameter (OD ≤ 168.3mm) | ±0.75% | |
| Outside Diameter (OD > 168.3mm) | ±0.75% (max ±3.2mm) | |
| Wall Thickness (OD 219-457mm) | +15%, -12.5% | |
| Wall Thickness (OD 508-610mm) | +19.5%, -8% | |
| Length | +100mm / -0mm (fixed lengths) |
Size Availability: ERW process typically produces X42 pipes up to 24-26 inches (610 mm) OD [citation:1, citation:2]. Larger diameters require LSAW or SSAW manufacturing.
Testing Requirements
| Test Type | Purpose | Applicability |
|---|---|---|
| Chemical Analysis | Verify composition per API 5L limits | Per heat |
| Tensile Test | Confirm yield and tensile strength | Per lot |
| Flattening Test | Check ductility | Required |
| Bend Test | Verify weld integrity | Required |
| Hydrostatic Test | Pressure integrity verification | Each pipe |
| NDT (Ultrasonic/Eddy Current) | Weld seam inspection | Standard practice |
| Impact Test (Charpy V-notch) | Low-temperature toughness | PSL2 only |
Common Applications
| Application | Description |
|---|---|
| Oil and Gas Transmission | Medium-pressure pipelines for crude oil and natural gas |
| Natural Gas Gathering Lines | Connecting wells to processing facilities |
| Water Transmission Mains | Large-diameter municipal and industrial water pipelines |
| Industrial Process Piping | Chemical plants, refineries, power generation |
| Gathering and Flow Lines | Upstream oil and gas operations |
| Structural Applications | Piling, bridge supports, construction |
PSL1 vs. PSL2: Key Differences for X42
| Feature | PSL1 | PSL2 | Significance |
|---|---|---|---|
| Carbon (C) max | 0.26% | 0.22% | Better weldability |
| Sulfur (S) max | 0.030% | 0.015% | Improved toughness, HIC resistance |
| Yield Strength | Min only | Min and Max | Prevents over-strength materials |
| Impact Testing | Not required | Mandatory | Guarantees low-temperature toughness |
| NDT Requirements | Standard | More stringent | Better defect detection |
| Typical Use | General service | Critical service, sour service, low temperature |
Key Advantages of X42 ERW
| Advantage | Description |
|---|---|
| Higher Strength than Grade B | 17% higher yield strength allows higher operating pressures or reduced wall thickness |
| Cost-Effective | More economical than seamless pipe for equivalent sizes |
| Excellent Weldability | Controlled chemistry ensures good field weldability |
| Wide Availability | Stocked globally in common sizes and schedules |
| Dual Certification | Often dual-certified with ASTM A53 Grade B for general piping applications |
| PSL2 Option | Available for critical service requiring guaranteed low-temperature toughness |
Important Considerations
1. Size Limitations
ERW manufacturing for X42 is typically limited to 24-26 inches (610 mm) OD
Larger diameters require LSAW or SSAW manufacturing
2. PSL1 vs. PSL2 Selection
PSL1: Suitable for general service, water lines, non-critical applications
PSL2: Required for low-temperature service, sour service, regulated pipelines (FERC, DOT)
3. Equivalent Grades
ISO 3183: L290
EN 10208-2: L290MB
GB/T 9711: L290
4. Mill Test Certificate
Typically provided as EN 10204 Type 3.1B with full test results
5. Coating Options
Black (bare): Standard mill finish
FBE (Fusion Bonded Epoxy): Corrosion protection
3LPE (3-layer polyethylene): Buried pipelines
Coal Tar Epoxy: Heavy-duty protection
Summary
API 5L X42 ERW pipe is a medium-strength line pipe widely used in oil and gas transmission, water distribution, and industrial applications. With minimum yield strength of 42,000 psi (290 MPa) – approximately 17% higher than Grade B – it offers an excellent balance of strength and cost-effectiveness for medium-pressure pipeline systems [citation:3, citation:6].
Available in diameters from 21.3 mm to 610 mm (1/2" to 24") with wall thicknesses from 1.8 mm to 25.4 mm, X42 ERW pipes are produced using high-frequency welding processes that ensure consistent quality and dimensional accuracy [citation:1, citation:2]. The specification offers two quality levels: PSL1 for general service and PSL2 for critical applications requiring guaranteed low-temperature toughness and sour service resistance .
Common applications include:
Medium-pressure oil and gas transmission pipelines
Natural gas gathering and distribution networks
Water transmission mains and industrial process piping
Structural applications such as piling and bridge supports [citation:2, citation:7]
When ordering, specify: API 5L, Grade X42, [PSL1 or PSL2], ERW, Size (OD x WT), Length, End Finish .
