EH36 LSAW Pipe Material
EH36 LSAW Pipe: High-Strength Shipbuilding Steel for Offshore and Marine Structures
Comprehensive material data for EH36 grade steel used in longitudinal submerged arc welded pipes, covering chemical composition, mechanical and thermal properties, equivalent standards, and applications.
Thermo-mechanical control processing (TMCP), normalizing, hot rolling, submerged arc welding (SAW/LSAW), cold forming (for pipes)
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EH36 LSAW Pipe Material Introduction
EH36 is a high-strength, low-alloy structural steel standardized under major classification society rules (ABS, DNV, LR, BV, CCS, etc.) for shipbuilding and offshore applications. With a minimum yield strength of 355 MPa and excellent toughness at -40°C, it is widely used in longitudinally submerged arc welded (LSAW) pipes for offshore platforms, jacket legs, and marine structures. Key characteristics include:
- High strength-to-weight ratio
- Good weldability and formability
- Reliable low-temperature impact toughness (EH grade: -40°C)
- Produced through normalizing or thermo-mechanical control process (TMCP)
- Available as plates and LSAW pipes with diameters up to 60 inches and above
EH36 LSAW Pipe Material Chemical Composition
Required chemical composition for EH36 steel according to ABS Rules (t ≤ 50 mm). Values are maximum unless a range is specified. Microalloying elements (Nb, V, Ti) are added to refine grain structure and improve strength and toughness. The carbon equivalent (Ceq) is typically limited to 0.38% to ensure good weldability.
| Element | Content (%) | Remarks |
|---|---|---|
| Carbon (C) | ≤ 0.18 | Ladle analysis |
| Manganese (Mn) | 0.90 – 1.60 | Depending on thickness |
| Silicon (Si) | 0.10 – 0.50 | |
| Phosphorus (P) | ≤ 0.030 | |
| Sulfur (S) | ≤ 0.030 | |
| Aluminum (Al) | ≥ 0.015 | Acid soluble or total Al |
| Niobium (Nb) | ≤ 0.05 | Microalloying |
| Vanadium (V) | ≤ 0.10 | Microalloying |
| Titanium (Ti) | ≤ 0.02 | Microalloying |
| Copper (Cu) | ≤ 0.35 | |
| Chromium (Cr) | ≤ 0.20 | |
| Nickel (Ni) | ≤ 0.40 | |
| Molybdenum (Mo) | ≤ 0.08 | |
| Nitrogen (N) | ≤ 0.012 | If Al added |
| Ceq | ≤ 0.38 | C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15 |
| Nb+V+Ti | ≤ 0.12 | Combined content |
EH36 LSAW Pipe Material Thermal and Electrical Physical Properties
Representative physical properties for EH36 steel at room temperature (20°C). These values are not specified in shipbuilding standards but are derived from typical low-alloy steel data and are provided for engineering design, heat transfer, and electrical calculations.
| Property | Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | At 20°C |
| Modulus of Elasticity (E) | 205 | GPa | At 20°C |
| Shear Modulus (G) | 80 | GPa | At 20°C |
| Poisson's Ratio (ν) | 0.30 | — | At 20°C |
| Thermal Expansion Coefficient (α) | 12.0 × 10&supmin;&sup6; | /K | 20 – 100°C |
| Thermal Conductivity (λ) | ~45 | W/(m·K) | At 20°C |
| Specific Heat Capacity (c) | ~460 | J/(kg·K) | At 20°C |
| Electrical Resistivity (ρe) | ~0.20 × 10&supmin;&sup6; | Ω·m | At 20°C |
EH36 LSAW Pipe Material Mechanical Properties
Mechanical properties for EH36 base material (plates used for LSAW pipe, thickness ≤ 50 mm) in accordance with classification society rules. LSAW pipes must meet these base material properties in the pipe body and the weld seam (after manufacturing). Charpy V-notch impact tests are performed at -40°C (EH grade).
| Property | Value | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) | ≥ 355 | MPa | Transverse, t ≤ 50 mm |
| Tensile Strength (Rm) | 490 – 620 | MPa | Transverse, t ≤ 50 mm |
| Elongation (A5) | ≥ 21 | % | Gauge length 50 mm |
| Impact Energy (KV, long.) | ≥ 34 (avg.) ≥ 24 (single) | J | Charpy V-notch, -40°C |
| Bend Test | No cracks | ° | 180° bending, d = 3a (t = specimen thickness) |
EH36 LSAW Pipe Material Equivalent Standards and Replaceable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| International (ABS) | ABS Rules | EH36 | Base standard |
| Norway/Germany (DNV) | DNV GL Rules | EH36 | Identical grade |
| United Kingdom (LR) | LR Rules | EH36 | Identical grade |
| France (BV) | BV Rules | EH36 | Identical grade |
| China (CCS) | CCS Rules | EH36 | Identical grade |
| Japan (NK) | NK Rules | EH36 | Identical grade |
| South Korea (KR) | KR Rules | EH36 | Identical grade |
| Italy (RINA) | RINA Rules | EH36 | Identical grade |
| Europe | EN 10225 | S355G10+M | Offshore structural steel, comparable properties |
| USA | ASTM A131/A131M | EH36 | Same specification for shipbuilding |
EH36 LSAW Pipe Material Application Introduction
EH36 LSAW pipes are a cornerstone in offshore and marine engineering due to their high strength, excellent weldability, and certified low-temperature toughness. They are used in the most demanding structural and pressure applications where reliability in harsh environments is paramount.
Product Applications: LSAW steel pipes for offshore jacket platforms, Jacket legs, brace members, and main piles, Conductor pipes for drilling operations, Structural pipes for topside modules and decks, Large-diameter pile pipes for marine terminals, Subsea flowline and riser pipes (where material is certified for such service), Offshore wind turbine monopile foundations and transition pieces
Processed into products: Jacket leg assemblies, Subsea structural braces, Deck truss members, Pile sleeves and connectors, Lifting padeyes and launch runners (cut from EH36 plate/pipe), Offshore flare boom structures (tubular sections), Turret structures for FPSOs
Application industries: Offshore Oil & Gas Exploration and Production, Shipbuilding and Ship Repair, Marine and Coastal Construction, Renewable Energy (Offshore Wind Turbine Foundations), Port and Harbor Infrastructure, Subsea Pipeline Systems
EH36 LSAW Pipe Material Similar Alternative Material Recommendations
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| International | API 5L | X52 (L360) | Line pipe steel, similar yield strength but different toughness requirements (lower temperature Charpy not mandatory) |
| USA | ASTM A572/A572M | Grade 50 [345] | High-strength low-alloy structural steel; not marine certified, impact properties vary |
| International (ABS) | ABS Rules | DH36 | Same strength, lower toughness (-20°C impact) – may be acceptable for less demanding conditions |
| International (ABS) | ABS Rules | FH36 | Higher toughness (-60°C impact), for very low-temperature applications |
| Europe | EN 10025-2 | S355J2 | General structural steel with 355 MPa yield and -20°C impact, not specifically for offshore/marine |
| Europe | EN 10025-4 | S355M/ML | Thermomechanical rolled fine-grain steel, comparable strength, sometimes used in structures |
Notes:
Welding considerations: The longitudinal welded seam in LSAW pipe must meet classification society toughness requirements identical to the base metal (EH36 impact at -40°C). Approved welding consumables and procedures (SAW) are mandatory. Post-weld heat treatment is generally not required unless specified by project specifications or for thick sections (>50mm).
Corrosion protection: EH36 pipes in marine environments typically require coating systems (e.g., three-layer polyethylene, fusion-bonded epoxy) or cathodic protection.
Supply conditions: Pipes are normally delivered with 3.1/3.2 certificates per EN 10204, including chemical, tensile, Charpy, and NDE (ultrasonic or radiographic) of the weld. Dimensional tolerances follow API 5L or project-specific requirements.
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