DNV E32 Shipbuilding Steel Coil
DNV E32 Shipbuilding Steel Coil | High Strength Marine Grade Plate & Coil
Complete reference data for DNV E32 shipbuilding steel coil: chemical composition, mechanical properties, thermal & electrical characteristics, international equivalents, and application guide from official DNV rules.
Cutting, Bending, Forming, Welding (SMAW, GMAW, SAW), Machining
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DNV E32 Shipbuilding Steel Coil Introduction
DNV E32 is a high-strength, normalized or TMCP shipbuilding steel grade defined by the DNV classification society (DNV GL rules). It offers a minimum yield strength of 315 MPa and guarantees excellent toughness down to -40°C (grade E). Widely used in hull structures and offshore platforms, DNV E32 steel coil is supplied in coiled form suitable for further cutting, forming and welding.
- Excellent low-temperature impact toughness (KV at -40 °C ≥ 31 J)
- Good weldability and formability
- Available in normalized (N) or thermo-mechanically controlled processed (TMCP) condition
- Compliant with IACS unified requirements for shipbuilding steels
DNV E32 Shipbuilding Steel Coil Chemical Composition
The chemical composition according to DNV Rules Pt.2 Ch.2 for grade E32. For fine grain practice, aluminium is added as grain refiner. Residual elements are controlled to ensure good weldability and toughness.
- Aluminium content and nitrogen control are essential for fine grain steel.
- Optional microalloying with Nb, V, and Ti must be reported.
- CEV (carbon equivalent) is limited when specified for improved weldability.
| Element | Standard Value (max or range) | Remarks |
|---|---|---|
| Carbon (C) | ≤ 0.18% | Ladle analysis |
| Silicon (Si) | 0.10 – 0.50% | Deoxidizer; improves strength |
| Manganese (Mn) | 0.90 – 1.60% | May be increased upon agreement for thick plates |
| Phosphorus (P) | ≤ 0.035% | Steelmaking residue |
| Sulfur (S) | ≤ 0.035% | For improved formability lower S may be agreed |
| Chromium (Cr) | ≤ 0.20% | Residual element |
| Nickel (Ni) | ≤ 0.40% | Residual element |
| Molybdenum (Mo) | ≤ 0.08% | Residual element |
| Copper (Cu) | ≤ 0.35% | If Cu content > 0.30% special measures for hot shortness may apply |
| Aluminium (Al, acid soluble) | ≥ 0.015% | Required when aluminium is used as grain refiner |
| Niobium (Nb) | ≤ 0.05% | Microalloying element |
| Vanadium (V) | ≤ 0.10% | Microalloying element |
| Titanium (Ti) | ≤ 0.02% | Microalloying element |
| Nitrogen (N) | ≤ 0.009% | When aluminium is not added as grain refiner, higher N may be accepted but must be stated |
DNV E32 Shipbuilding Steel Coil Thermal & Electrical Physical Properties
The values below are typical for DNV E32 grade steel at room temperature (20 °C) unless otherwise indicated. These reference data are useful for design calculations but are not part of the mandatory classification requirements.
- Specific heat and thermal conductivity vary with temperature.
- Data apply to normalized or TMCP condition; properties are isotropic in the rolling plane.
| Property | Typical Value | Unit | Test Condition / Remarks |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | At 20 °C |
| Elastic Modulus (E) | 210 | GPa | At 20 °C, longitudinal |
| Shear Modulus (G) | ~ 81 | GPa | Calculated from E and ν |
| Poisson's Ratio (ν) | 0.3 | – | Elastic range, room temperature |
| Thermal Expansion Coefficient (α) | 12 × 10⁻⁶ | 1/K | Average between 20 °C and 100 °C |
| Thermal Conductivity (λ) | ~ 50 | W/(m·K) | At 20 °C |
| Specific Heat Capacity (c) | ~ 460 | J/(kg·K) | At 20 °C |
| Electrical Resistivity (ρₑ) | ~ 0.20 × 10⁻⁶ | Ω·m | At 20 °C |
DNV E32 Shipbuilding Steel Coil Mechanical Properties
Mechanical properties according to DNV Rules Pt.2 Ch.2 for thickness ≤ 100 mm. The steel must meet both room temperature tensile and low temperature impact requirements.
- Yield and tensile strength values apply for transverse specimens unless otherwise agreed.
- The impact test temperature of -40 °C characterizes the 'E' (extra) grade.
- Bending test mandrel diameters depend on plate thickness.
| Property | Standard Requirement | Unit | Test Condition / Remarks |
|---|---|---|---|
| Yield Strength (ReH) | ≥ 315 | MPa | Thickness ≤ 100 mm, transverse or longitudinal as per specification (commonly transverse) |
| Tensile Strength (Rm) | 440 – 590 | MPa | Thickness ≤ 100 mm |
| Elongation (A) | ≥ 22 | % | Longitudinal test piece, gauge length 5.65√S₀; for transverse elongation, a reduced value (≥ 20%) may be applied |
| Impact Energy (KV) | ≥ 31 (average) / ≥ 22 (single) | J | Charpy-V notch, test temperature -40 °C, full-size specimen (10×10 mm), longitudinal direction |
| Bend Test (Mandrel Diameter) | 3t (t ≤ 50 mm) / 4t (50 < t ≤ 100 mm) | – | Bending through 180° without cracking; t = specimen thickness |
DNV E32 Shipbuilding Steel Coil Directly Equivalent Material Standards & Replaceable Grades
| Country / Region | Standard / Classification Society | Grade | Remarks |
|---|---|---|---|
| International | ABS Rules | EH32 | American Bureau of Shipping – identical toughness & strength requirements |
| International | LR Rules | EH32 | Lloyd's Register – interchangeable with DNV E32 for shipbuilding |
| International | BV Rules | EH32 | Bureau Veritas – same grade with -40 °C impact test |
| International | CCS Rules | EH32 | China Classification Society – equivalent to DNV E32 |
| International | NK Rules | KE32 | Nippon Kaiji Kyokai – symbol 'KE32' equivalent to E grade |
| International | KR Rules | EH32 | Korean Register – identical in mechanical and toughness requirements |
| International | RINA Rules | EH32 | Registro Italiano Navale – matches DNV E32 specifications |
| International | RS Rules | EH32 | Russian Maritime Register of Shipping – same strength and toughness class |
| International | IACS UR W11 | EH32 | Unified Requirement for normal and high strength hull structural steels – cover EH32 grade |
DNV E32 Shipbuilding Steel Coil Application Introduction
DNV E32 steel coil is primarily designed for the construction of ship hulls and offshore structures that require high strength and excellent low-temperature toughness. With its certified properties from a recognized classification society, the material is ideal for critical primary and secondary structural members.
- Frequently supplied with third-party certification (DNV certificates) to streamline project compliance.
- Thicknesses up to 100 mm are covered by standard rules; thicker plates may be subject to additional procedures.
Product Applications: Hull bottom plates & shell plating, Main deck and strength deck plating, Longitudinal stiffeners and beams, Transverse frames and bulkheads, Offshore platform deck sections, Wind turbine foundation jackets (marine environment)
Processed into products: Hull shell plates and coil-cut strips, Stiffener profiles (flat bars, bulb flats, angles) produced from coil, Deck panels and ramp components, Hatch coamings and coaming stays, Offshore module support beams and columns, Cargo tank boundaries (after additional corrosion testing)
Application industries: Shipbuilding (merchant vessels, tankers, bulk carriers, container ships), Offshore & Marine Engineering (fixed platforms, jack-up rigs, FPSOs), Naval and Defence Shipbuilding, Heavy Structural Fabrication for Arctic/Marine Environment
DNV E32 Shipbuilding Steel Coil Closely Similar / Alternative Materials for Consideration
| Country / Region | Standard | Grade | Remarks / Comparative Analysis |
|---|---|---|---|
| Europe | EN 10025-3 | S355N / S355NL | Normalized fine-grain structural steel; yield 355 MPa, comparable strength but -50 °C impact for NL (33 J). Needs additional agreement for marine application and through-thickness properties. |
| USA | ASTM A131 / A131M | EH32 | ASTM shipbuilding steel with equivalent tensile and impact properties; directly corresponds to DNV E32. |
| Japan | JIS G 3106 | SM490YA (normalized) or SM490B | Higher tensile strength (490-610 MPa) weldable structural steel; requires impact test specification to match -40 °C toughness. Suitable substitution for some non-classed structural projects. |
| China | GB 712 | EH32 | Chinese shipbuilding steel standard; the EH32 grade mirrors DNV E32 in all essential aspects. |
Notes:
Additional stipulations often applied:
- Ultrasonic (UT) testing in accordance with EN 10160 or agreed specification for internal soundness.
- Through-thickness (Z-grade) properties, e.g., Z25 or Z35, according to EN 10164 or DNV rules when required for highly restrained joints.
- Carbon equivalent (CEV / CET) limitations to ensure cold cracking resistance during welding.
- Surface condition: as-rolled, pickled and oiled, or blast cleaned upon request.
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