ASTM A252 Grade 2 Longitudinal Submerged Arc Welding (LSAW) Pipe
Basic Overview
ASTM A252 Grade 2 LSAW pipe is the most commonly used grade in the ASTM A252 specification for welded steel pipe piles. It is a carbon steel pipe manufactured using the Longitudinal Submerged Arc Welding (LSAW) process, specifically designed for foundation piling and structural support applications where reliable strength and cost-effectiveness are required .
Name Explanation
| Part | Meaning |
|---|---|
| ASTM | ASTM International (American Society for Testing and Materials) |
| A252 | Standard specification for welded and seamless steel pipe piles |
| Grade 2 | The standard, most widely used grade in the ASTM A252 specification – suitable for most general piling applications |
| Longitudinal Submerged Arc Welding (LSAW) | Manufacturing process – steel plates are formed and welded along a single straight longitudinal seam using submerged arc welding with filler metal added |
Key Features of ASTM A252 Grade 2 LSAW Pipe
| Feature | Description |
|---|---|
| Material Type | Low carbon steel / low-alloy carbon steel – provides good weldability and reliable strength for foundation applications |
| Manufacturing | LSAW (Longitudinal Submerged Arc Welding) – plates formed by UOE, JCOE, or roll bending processes, then double-sided submerged arc welded |
| Primary Application | Piling foundations, structural supports, load-bearing members for civil engineering and construction |
| Yield Strength | 240 MPa (35,000 psi) minimum |
| Tensile Strength | 415 MPa (60,000 psi) minimum |
| Elongation | 25% minimum (in 2 inches) |
| Typical Diameters (LSAW) | 304.8 mm to 1820 mm (12" to 72") |
| Typical Wall Thickness | 5 mm to 63.5 mm |
| Length | 6 m to 32 m standard; up to 70 m available from some manufacturers |
Chemical Composition (ASTM A252 Grade 2)
| Element | Heat Analysis (max %) | Product Analysis (max %) | Notes |
|---|---|---|---|
| Carbon (C) | 0.26 | 0.30 | Low carbon for weldability |
| Manganese (Mn) | 1.35 - 1.6 | 1.40 - 1.6 | Provides basic strength |
| Phosphorus (P) | 0.050 | 0.050 | Tight control for toughness |
| Sulfur (S) | 0.030 - 0.045 | 0.045 | Controlled for weld quality |
| Silicon (Si) | 0.45 max | Not specified | Deoxidizer |
Note: The steel shall contain no more than 0.050% phosphorus . For each reduction of 0.01% below the specified maximum for carbon, an increase of 0.06% above the specified maximum for manganese is permitted, up to a maximum of 1.50% for heat analysis and 1.60% for product analysis .
Mechanical Properties Comparison: ASTM A252 Grades
| Property | Grade 1 | Grade 2 | Grade 3 |
|---|---|---|---|
| Yield Strength (min) | 205 MPa (30 ksi) | 240 MPa (35 ksi) | 310 MPa (45 ksi) |
| Tensile Strength (min) | 345 MPa (50 ksi) | 415 MPa (60 ksi) | 455 MPa (66 ksi) |
| Elongation (min) | 30% | 25% | 20% |
| Usage Frequency | Light-load applications | Most commonly used | High-load applications |
Sources:
LSAW Manufacturing Process for ASTM A252 Grade 2
Process Steps
| Step | Description |
|---|---|
| 1. Plate Selection | High-quality steel plates are selected according to ASTM A252 requirements |
| 2. Edge Preparation | Plate edges are beveled to create a V-shaped groove for welding |
| 3. Forming | Plates are formed into cylindrical shapes using press, UOE, JCOE, or roll bending machines |
| 4. Tack Welding | Formed plates are tack-welded to maintain shape before final welding |
| 5. Submerged Arc Welding | Multi-wire SAW applies internal weld, then external weld (double-sided) for full penetration |
| 6. Mechanical Expanding | Pipe may be expanded to precise dimensions to achieve tight tolerances |
| 7. Heat Treatment | May undergo stress relief heat treatment when specified to improve toughness |
| 8. Inspection & Testing | Non-destructive tests including ultrasonic examination and hydrostatic testing |
| 9. Finishing | End beveling (per ANSI B16.25), coating application as specified |
Forming Methods Available
| Method | Description | Suitability for Grade 2 |
|---|---|---|
| UOE | Plate pressed into U-shape, then O-shape, mechanically expanded after welding | Suitable |
| JCOE | Progressive J-C-O forming steps, expanded after welding | Suitable – high forming accuracy |
| RBE (Roll Bending) | Plate progressively rolled into cylinder | Suitable for smaller production runs |
Size Availability
| Parameter | Range | Notes |
|---|---|---|
| Outside Diameter (LSAW) | 304.8 mm to 1820 mm (12" to 72") | Up to 4500mm available from some manufacturers |
| Wall Thickness | 5 mm to 63.5 mm | Up to 100mm available from some manufacturers |
| Length | 6 m to 32 m standard; up to 70 m available | Longer lengths reduce field splicing |
| End Finish | Plain ends, beveled ends per ANSI B16.25 | Beveled for welding standard |
Testing & Inspection Requirements
| Test Type | Purpose | Requirement |
|---|---|---|
| Chemical Analysis | Verify composition meets ASTM A252 limits | Per heat analysis |
| Tensile Test | Confirm yield and tensile strength | Per lot |
| Flattening Test | Check ductility | Required |
| Bend Test | Verify weld integrity | Required |
| Hydrostatic Test | Proof of leak-tightness | Each pipe tested |
| Ultrasonic Examination | Detect internal defects | 100% of weld seam when specified |
| Radiographic Examination (X-ray) | Verify weld quality | When specified |
| Dimensional Inspection | Verify OD, wall thickness, straightness | 100% |
| Impact Test | Verify toughness | When specified |
| Visual Inspection | Surface condition, weld appearance | 100% |
Mill Test Certificate: EN 10204 / 3.1B typically provided
Applications of ASTM A252 Grade 2 LSAW Pipe
Grade 2 is the standard choice for most foundation and structural applications:
| Application Area | Specific Uses |
|---|---|
| Building Foundations | High-rise building foundations, ensuring structural stability for long-term use |
| Bridge Construction | Main pier pile foundations to support bridge weight; main load-bearing components |
| Ports and Wharves | Withstand ship berthing impact and wave erosion, requiring balanced strength and corrosion resistance |
| Civil Engineering | Provides good load-carrying capacity for various soil conditions, effectively resisting soil side pressure and settlement |
| Water Conservancy Projects | Dam reinforcement, drainage systems, hydropower station foundation construction |
| Oil and Gas Pipelines | Under certain conditions, may be used in buried pipelines for safety and durability |
| Marine Construction | Dock construction, withstanding heavy loads and maritime environmental pressures |
Note: Grade 2 is the most commonly used grade in ASTM A252, suitable for most general piling applications where moderate strength requirements exist .
Coating & Protection Options
| Coating Type | Application |
|---|---|
| Black (bare) | Standard mill finish, indoor use |
| Varnish / Anti-rust oil | Temporary protection during transit |
| Black painting | Basic corrosion protection |
| FBE (Fusion Bonded Epoxy) | Corrosion protection for buried service |
| 3LPE (3-layer polyethylene) | Buried pipelines, harsh environments |
| Coal Tar Epoxy | Heavy-duty protection |
| Bitumen coating | Buried service |
| Cathodic protection | Can be applied to extend service life |
Comparison: ASTM A252 Manufacturing Types
| Aspect | LSAW (Longitudinal) | ERW | SSAW (Spiral) | Seamless |
|---|---|---|---|---|
| Weld Seam | Single straight seam | Single straight seam | Continuous spiral seam | No seam |
| Diameter Range | 12" to 72"+ | ≤ 24" typical | 8" to 120"+ | ≤ 24" typical |
| Wall Thickness | Up to 63.5 mm | Medium | Medium | Thick available |
| Typical Application | Piling, foundations, structural | Smaller piling | Large diameter piling | Heavy-load special applications |
| Key Advantage | High strength, good dimensional accuracy | Cost-effective for small diameters | Very large diameters | Highest strength, uniform force characteristics |
Advantages of ASTM A252 Grade 2 LSAW Pipe
| Advantage | Description |
|---|---|
| Most Commonly Used Grade | Grade 2 is the standard choice for most piling applications, offering the best balance of strength and cost |
| Cost-Effective | Provides reliable strength at an economical price point for general construction needs |
| Large Diameter Capability | LSAW process enables production of large-diameter piles (up to 72"+), ideal for major infrastructure projects |
| Thick Walls | Suitable for applications requiring substantial wall thickness (up to 63.5 mm) |
| High Structural Integrity | Single longitudinal seam with full-penetration double-sided welding ensures robust and reliable seams |
| Excellent Dimensional Accuracy | Mechanical expanding achieves tight tolerances, ensuring precise control over pipe dimensions |
| Flexible Lengths | Can produce long piles (up to 70 m) reducing field splicing and improving construction efficiency |
| Quality Assurance | Extensive testing ensures compliance with ASTM standards and high-quality output |
| Corrosion Resistance | Various coating options available to extend service life in harsh environments |
| Seismic Resistance | Good flexibility and impact resistance, suitable for earthquake-prone areas |
Performance Characteristics
| Characteristic | Description |
|---|---|
| High Strength | Capable of withstanding high pressure and stress |
| High Durability | Withstands heavy loads and extreme environmental conditions |
| Convenience of Construction | Long lengths reduce on-site splicing work; quick installation via welding or flange connections |
| Adaptability | Suitable for various soil conditions and complex geological environments |
| Corrosion Resistance | Can be enhanced through 3PE coating, epoxy powder coating, or cathodic protection |
Important Selection Notes
1. Grade 2 vs. Other Grades
Grade 2 is suitable for most general foundation applications where moderate strength requirements exist
For light-load, temporary, or non-critical applications, Grade 1 may be sufficient
For heavy-duty, high-load projects (e.g., major bridges, high-rise buildings), Grade 3 provides the highest strength
2. When to Choose ASTM A252 Grade 2 LSAW
Most building foundations – high-rise buildings, industrial facilities
Bridge construction – main pier pile foundations
Ports and marine structures – docks, wharves
Water conservancy projects – dam reinforcement, drainage systems
General civil engineering – where reliable load-carrying capacity is required
3. Manufacturing Process Selection
LSAW is preferred for:
Large diameters (≥12")
Thick wall applications
Projects requiring long pile lengths
When straight seam is specified for easier NDT
Applications requiring high dimensional accuracy
4. Corrosion Protection
For permanent structures, specify appropriate coating based on environmental conditions
Options include FBE, 3LPE, coal tar epoxy, or bitumen coating
Cathodic protection can be applied for enhanced longevity
For marine environments, corrosion resistance is critical
5. Certification
Standard: EN 10204 3.1 (manufacturer's independent testing)
Ensure Mill Test Certificate includes: chemical composition, mechanical properties, hydrostatic test results
6. Design Considerations
Steel pipe serves as permanent load-bearing component or forming shell for concrete piles
Pipes must undergo hydrostatic, bending, flattening, and other tests to ensure structural integrity
Longer lengths (up to 70m) reduce field splicing and improve installation efficiency
7. Comparison with API 5L
ASTM A252 is specifically for piling/foundation applications, not for pressure service
API 5L is for oil/gas transmission pipelines
Yield strength of A252 Grade 2 (240 MPa) is similar to API 5L Grade B (241 MPa)
Final Takeaway: ASTM A252 Grade 2 LSAW Pipe is the standard, most commonly used large-diameter welded pipe pile for foundation applications requiring reliable strength and cost-effectiveness. With minimum yield strength of 35,000 psi (240 MPa) , it offers the optimal balance of strength and economy for most general construction needs . The LSAW manufacturing process enables production of pipes from 12" to 72" diameter with wall thicknesses up to 63.5 mm and lengths up to 70 m, significantly reducing field splicing requirements . Grade 2 is the preferred choice for building foundations, bridge construction, port facilities, water conservancy projects, and general civil engineering applications where moderate load-bearing capacity is required. Its combination of high structural integrity, dimensional accuracy, and corrosion resistance options makes it the most versatile and widely specified grade in the ASTM A252 standard .
