LR EH32 Shipbuilding Steel Coil
LR EH32 Shipbuilding Steel Coil - High-Strength Marine Structural Steel per Lloyd's Register Rules
Comprehensive material analysis of LR EH32 shipbuilding steel coil: chemical composition, mechanical properties, thermal & electrical properties, international equivalents, and typical applications.
Hot rolling, normalizing, TMCP, cold forming, welding, flame cutting, machining
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LR EH32 Shipbuilding Steel Coil Introduction
LR EH32 is a high-strength, weldable structural steel specifically designed for shipbuilding and marine applications according to the Lloyd's Register (LR) Rules for Materials. It belongs to the EH32 grade category, where 'EH' indicates guaranteed impact toughness at -40 °C and '32' refers to a minimum yield strength of 315 MPa.
- Excellent low-temperature toughness
- Good weldability and formability
- Supplied in coil form for efficient processing
Typical delivery condition is as-rolled, normalized, or thermo-mechanically controlled processed (TMCP), depending on thickness and customer requirements. Widely used in hull structures, stiffeners, decks, and other critical components exposed to cold marine environments.
LR EH32 Shipbuilding Steel Coil Chemical Composition
Based on IACS UR W11 for H32 grade (EH32) and Lloyd's Register Rules. The steel is fully killed and contains fine grain elements. Key elements: Manganese provides strength, micro-alloying elements (Nb, V, Ti) ensure grain refinement.
- Phosphorus and sulfur are kept low for toughness.
- Nitrogen is controlled when aluminum is added.
| Chemical Element | Standard Value (max or range) | Remarks |
|---|---|---|
| Carbon (C) | ≤0.18 | Ladle analysis |
| Manganese (Mn) | 0.90 – 1.60 | Ladle analysis |
| Silicon (Si) | ≤0.50 | Ladle analysis |
| Phosphorus (P) | ≤0.035 | Ladle analysis |
| Sulfur (S) | ≤0.035 | Ladle analysis |
| Aluminum (Al, acid soluble) | ≥0.015 (if Al treated) | Minimum for fine grain practice |
| Niobium (Nb) | ≤0.05 | Micro-alloying |
| Vanadium (V) | ≤0.10 | Micro-alloying |
| Titanium (Ti) | ≤0.02 | Micro-alloying |
| Copper (Cu) | ≤0.35 | Residual element |
| Chromium (Cr) | ≤0.20 | Residual element |
| Nickel (Ni) | ≤0.40 | Residual element |
| Molybdenum (Mo) | ≤0.08 | Residual element |
| Nitrogen (N) | ≤0.009 (if Al treated) | Ladle analysis, for aluminium treated steel |
| Nb + V + Ti | ≤0.12 | Combined micro-alloying limit |
LR EH32 Shipbuilding Steel Coil Thermal & Electrical Physical Properties
Typical data for EH32 type steel at room temperature unless noted. These values are not guaranteed but serve as generic design estimates.
- Density is standard for low-alloy steel.
- Thermal conductivity and expansion are averaged for the 20–100 °C range.
| Property | Typical Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | 20 °C |
| Elastic modulus (E) | 205 | GPa | Ambient temperature |
| Shear modulus (G) | 80 | GPa | Estimated from E and ν |
| Poisson's ratio (ν) | 0.29 | Elastic range | |
| Thermal expansion coefficient (α) | 12.1 × 10⁻⁶ | /K | 20–100 °C |
| Thermal conductivity (λ) | 50 | W/(m·K) | 20 °C |
| Specific heat capacity (c) | 460 | J/(kg·K) | 20 °C |
| Electrical resistivity (ρₑ) | 0.20 × 10⁻⁶ | Ω·m | 20 °C |
LR EH32 Shipbuilding Steel Coil Mechanical Properties
Properties for plate/coil thickness ≤ 100 mm, normally delivered in as-rolled, normalized or TMCP condition. Impact test temperature: -40 °C (longitudinal or transverse). Bending test: 180° over specified former diameter without cracking. Values can vary with thickness and product form.
- Elongation measured on gauge length 5.65√S₀.
- Impact specimens: 10×10 mm (sub-size values proportional).
| Property | Standard Requirement Value | Unit | Test Condition |
|---|---|---|---|
| Yield strength (ReH) | 315 min | MPa | Thickness ≤ 50 mm; for 50–100 mm see note 1 |
| Tensile strength (Rm) | 440 – 590 | MPa | Transverse or longitudinal, all thickness |
| Elongation (A) | 22 min | % | Longitudinal, 5.65√S₀ gauge; transverse 20% min |
| Charpy impact energy (KV, -40 °C) | 31 min (longitudinal) / 24 min (transverse) | J | 10×10 mm standard specimen |
| Bending test | No cracks | 180° bend, former dia. 3× thickness (t ≤ 25 mm) |
LR EH32 Shipbuilding Steel Coil Completely Equivalent Material Standards & Substitute Grades
| Country/Region | Standard / Classification Society | Grade | Remarks |
|---|---|---|---|
| USA | American Bureau of Shipping (ABS) | EH32 | Identical IACS UR W11 requirements |
| Norway/Germany | DNV (now DNV GL) | E32 (EH32) | Equivalent grade per DNV rules |
| France | Bureau Veritas (BV) | EH32 | Same technical requirements |
| China | China Classification Society (CCS) | EH32 | Direct equivalent |
| South Korea | Korean Register (KR) | EH32 | Same IACS UR W11 specification |
| Japan | Nippon Kaiji Kyokai (Class NK) | KE32 | KE32 matches EH32 impact test temperature (-40 °C) |
| Italy | Registro Italiano Navale (RINA) | RE32 | E-grade corresponds to -40 °C impact |
LR EH32 Shipbuilding Steel Coil Application Introduction
LR EH32 steel coil is primarily intended for welded ship structures operating in cold environments, including Arctic and North Sea conditions. Its high strength-to-weight ratio and reliable toughness make it suitable for a wide range of marine and offshore engineering projects.
- Excellent weldability using all conventional processes
- Good formability for bending, profiling, and cold rolling
- Often supplied with additional certification (ultrasonic testing, Z35 properties) for critical applications
Product Applications: Ship hull plates and skins, Stiffened panels for decks, bulkheads, and double bottoms, Longitudinal stringers, webs, and frames, Transition ring plates in offshore wind monopiles, Shipbuilding coil for further slitting, cutting, or roll-forming
Processed into products: Main deck plates and sheer strakes, Bottom shell and bilge plates, Transverse and longitudinal bulkheads, Web frames and stiffeners, Floor plates and brackets, Brace and column elements of offshore structures
Application industries: Commercial shipbuilding (bulk carriers, containers, tankers), Naval architecture & defense (military vessels), Offshore oil & gas platforms and modules, Renewable energy (offshore wind turbine foundations, substations), Marine equipment and heavy machinery
LR EH32 Shipbuilding Steel Coil Similar / Nearly Equivalent Material Substitutes
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10025-4 (TMCP) | S355ML | Minimum yield 355 MPa, better strength; toughness down to -50 °C; higher Mn content |
| Europe | EN 10025-3 (Normalized) | S355NL | Normalized fine‑grain steel, yield 355 MPa, impact -50 °C, not identical but structurally similar |
| USA | ASTM A572 / A709 | Grade 50 (345 MPa) | Higher strength but less specific low-temperature toughness unless S1 or T1 notch toughness options added |
| API | API Spec 2H | Grade 50 (2H Gr.50) | Offshore structural steel, yield 345–413 MPa, Z-grade optional, comparable weldability |
Notes:
Special requirements: EH32 may be ordered with through-thickness properties (Z15, Z25, Z35) according to EN 10164 or LR rules for restraint-welded joints to avoid lamellar tearing.
- Ultrasonic testing according to EN 10160 or LR requirements is common for plates > 12 mm.
- Surface condition and dimensional tolerances comply with EN 10029 or equivalent LR standards for hot-rolled products.
- CEV (carbon equivalent value) is controlled to ensure weldability; typically CEV ≤ 0.40% for TMCP, ≤ 0.43% for normalized.
- The steel is delivered with LR inspection certificate 3.1 or 3.2 per EN 10204.
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