To manufacture Longitudinal Submerged Arc Welded (LSAW) steel pipes with the given specifications, we need to use high-strength steel plates that match the respective grades and thicknesses. Below is a breakdown of the suitable steel sheets for each pipe size and grade.

1. Required Mild Steel Plates for LSAW Pipes

Steel Grade: API 5L X65 / S460 (High Strength for Structural & Offshore Applications)

Pipe Size Required Plate Thickness & Grade
1420 mm OD X 25.8 mm Th X 12 mtr API 5L X65 / S460, 26 mm thick steel plate
1220 mm OD X 25.8 mm Th X 12 mtr API 5L X65 / S460, 26 mm thick steel plate
1016 mm OD X 20 mm Th X 12 mtr API 5L X65 / S460, 20 mm thick steel plate
48″ (1219 mm) OD X 25.8 mm Th X 12 mtr API 5L X65 / S460, 26 mm thick steel plate
36″ (914 mm) OD X 25 mm Th X 12 mtr API 5L X65 / S460, 25 mm thick steel plate

Steel Grade: API 5L X52 / EN 10219 / S355J2H (High Strength, Structural Applications)

Pipe Size Required Plate Thickness & Grade
610 mm OD X 16 mm Th X 12mtr API 5L X52 / EN 10219 / S355J2H, 16 mm thick steel plate

Steel Grade: API 5L X52 / S420 (Heavy-Duty Piling Applications)

Pipe Size Required Plate Thickness & Grade
1800 mm OD X 40 mm Th X 31.5 mtr API 5L X52 / S420, 40 mm thick steel plate
1500 mm OD X 30 mm Th X 31.5 mtr API 5L X52 / S420, 30 mm thick steel plate
1066 mm OD X 24.6 mm Th X 34 mtr API 5L X52 / S420, 25 mm thick steel plate
914 mm OD X 20 mm Th X 34 mtr API 5L X52 / S420, 20 mm thick steel plate

2. Steel Plate Selection Criteria

To ensure quality LSAW pipe manufacturing, the steel plates must have:

  • Good weldability (low carbon equivalent for better welding properties).
  • High yield & tensile strength to match the API & EN standards.
  • Controlled thickness tolerance for precise welding and bending.

3. Recommended Steel Plate Standards

Steel Grade Applicable Standard
API 5L X65 API 5L, ISO 3183
API 5L X52 API 5L, ISO 3183
S460 EN 10025-3
S420 EN 10025-4
EN 10219 EN Standard for structural pipes
S355J2H EN 10210-1 for hot-finished structural pipes

4. Manufacturing Process for LSAW Pipes

  1. Steel Plate Cutting – Cut to the required width for pipe diameter.
  2. Edge Beveling – Prepared for submerged arc welding (SAW).
  3. Forming (Bending / Pressing) – Converted into “J”, “C”, and “O” shape.
  4. LSAW Welding – Submerged Arc Welding (SAW) to ensure high-quality, durable welds.
  5. Ultrasonic & Radiographic Testing – Ensures weld integrity and strength.

For material sourcing and fabrication details for manufacturing LSAW (Longitudinal Submerged Arc Welded) steel pipes, we have to break it down into three key areas:

  1. Material Sourcing: Where & How to Source Steel Plates
  2. Fabrication & Welding Process
  3. Testing & Quality Control

1. Material Sourcing: Where & How to Source Steel Plates?

Since you need API 5L X65, X52, S460, S420, and S355J2H steel plates, you have multiple sourcing options:

A. Domestic Steel Suppliers (India)

If you are sourcing from India, consider major steel manufacturers like:

  • SAIL (Steel Authority of India Ltd.) – Supplies IS 2062 E350/S355 plates.
  • JSW Steel – Produces API 5L X52, X65 grade steel.
  • Tata Steel – Supplies high-strength steel plates for oil & gas pipelines.
  • Essar Steel (AM/NS India) – Specializes in LSAW-grade steel.

B. International Steel Plate Suppliers

If you need imported plates, consider:

  • POSCO (South Korea) – Supplies API X65/X52 grade plates.
  • Baosteel (China) – Large supplier of API & EN standard plates.
  • Nippon Steel (Japan) – High-quality S460/S420 structural steel.
  • ArcelorMittal (Europe) – Specializes in S355J2H & EN 10219 plates.

2. Fabrication & Welding Process for LSAW Pipes

Once you procure the right steel plates, the LSAW pipe manufacturing process involves these steps:

Step 1: Steel Plate Cutting & Edge Preparation

  • Plates are cut to the required width based on the pipe diameter.
  • Edge beveling is done to prepare for welding.

Step 2: Pipe Forming (Press Bending / Roll Bending)

  • Steel plates are shaped into a cylindrical form using the JCOE method:
    • J-forming → C-forming → O-forming
  • Large-diameter pipes (e.g., 1800 mm OD, 40 mm thick) are formed in multiple steps using a press.

Step 3: Longitudinal Submerged Arc Welding (LSAW)

  • Pipes are welded in two stages:
    • Inside welding – First weld pass inside the pipe.
    • Outside welding – Final weld pass externally for reinforcement.
  • Automatic submerged arc welding (SAW) is used for strong, defect-free welds.

💡 Welding Consumables:

  • Electrode: AWS A5.17 EM12K or A5.23 F7A2-EM12K
  • Flux: Lincoln 801/880 or ESAB OK 10.81

3. Testing & Quality Control for LSAW Pipes

To meet API 5L & EN standards, pipes undergo rigorous testing before dispatch:

A. Non-Destructive Testing (NDT)

  1. Ultrasonic Testing (UT) – Detects internal weld flaws.
  2. Radiographic Testing (RT/X-ray) – Ensures full penetration welds.
  3. Magnetic Particle Testing (MPT) – Checks surface cracks.

B. Destructive Testing

  1. Tensile Test – Verifies steel’s yield & tensile strength.
  2. Charpy Impact Test – Ensures toughness at low temperatures.
  3. Hardness Test – Confirms compliance with API & EN requirements.

C. Dimensional & Hydrostatic Testing

  • Pipe ovality & straightness check
  • Hydrostatic Pressure Test at 1.5x working pressure

💡 Certification Required:

  • EN 10204 3.1/3.2 Mill Test Certificate (MTC)
  • API 5L PSL2 Compliance for oil & gas pipelines
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