BV E420 Shipbuilding Steel Coil
BV E420 Shipbuilding Steel Coil - High Strength Structural Plate for Marine Applications
BV E420 is a high-strength shipbuilding steel certified by Bureau Veritas with minimum yield strength of 420 MPa. Ideal for hull structures, offshore platforms, and marine equipment requiring excellent toughness at low temperatures.
Hot rolling, thermo-mechanical controlled processing (TMCP), normalizing, quenching and tempering (as agreed)
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BV E420 Shipbuilding Steel Coil Introduction
BV E420 is a high-strength structural shipbuilding steel grade certified by Bureau Veritas (BV), meeting the requirements of BV Rules for Materials and Welding. It belongs to the high-strength hull structural steel series with a specified minimum yield strength of 420 MPa. This steel offers excellent weldability, good cold-forming properties, and superior low-temperature impact toughness, making it suitable for critical ship components and offshore structures.
- Minimum yield strength of 420 MPa in thicknesses up to 50 mm
- Good notch toughness down to -40 °C (E-grade)
- Controlled carbon equivalent (CEV) ensures reliable weldability
- Available in various delivery conditions such as normalized, thermo-mechanical rolled, or quenched and tempered
BV E420 Shipbuilding Steel Coil Chemical Composition
The chemical composition of BV E420 steel is controlled to achieve the required mechanical properties and weldability. Typical limits according to BV Rules for thicknesses ≤50 mm are given below. Fine-grained practice and microalloying elements may be added. Carbon equivalent (CEV) is restricted to ≤0.43 for thicknesses up to 50 mm.
| Chemical Element | Standard Value | Remarks |
|---|---|---|
| Carbon (C) | ≤0.20 | |
| Manganese (Mn) | 0.90 – 1.60 | |
| Silicon (Si) | 0.10 – 0.50 | |
| Phosphorus (P) | ≤0.030 | |
| Sulfur (S) | ≤0.030 | |
| Aluminum (Al) total | ≥0.015 | Minimum acid-soluble content |
| Niobium (Nb) | ≤0.05 | Optional microalloying element |
| Vanadium (V) | ≤0.10 | Optional microalloying element |
| Titanium (Ti) | ≤0.02 | Optional microalloying element |
| Nitrogen (N) | ≤0.012 | For Al-killed fine-grain steels |
| Chromium (Cr) | ≤0.25 | Residual element limit |
| Nickel (Ni) | ≤0.40 | Residual element limit |
| Molybdenum (Mo) | ≤0.08 | Residual element limit |
| Copper (Cu) | ≤0.35 | Residual element limit |
| Carbon Equivalent (CEV) | ≤0.43 | For thickness ≤50 mm, formula: CEV = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15 |
BV E420 Shipbuilding Steel Coil Physical Properties
Physical properties are not specified in BV rules but are essential for design. The values below are typical for high-strength low-alloy steel of similar composition and are provided for reference. They may vary slightly depending on processing and exact chemistry.
| Property | Standard Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | Room temperature |
| Modulus of elasticity (E) | 210 | GPa | Room temperature |
| Shear modulus (G) | 80 | GPa | Room temperature |
| Poisson's ratio (ν) | 0.3 | – | Room temperature |
| Thermal expansion coefficient (α) | 12 | 10⁻⁶/K | 20 – 100 °C |
| Thermal conductivity (λ) | 52 | W/(m·K) | Room temperature |
| Specific heat capacity (c) | 486 | J/(kg·K) | Room temperature |
| Electrical resistivity (ρ_e) | 0.16 | μΩ·m | Room temperature |
BV E420 Shipbuilding Steel Coil Mechanical Properties
Mechanical properties of BV E420 steel are determined on standard test specimens obtained from the flat product. The following values apply for thicknesses up to 50 mm in the longitudinal direction unless otherwise noted. Test methods conform to ISO or equivalent BV-approved standards.
| Property | Standard Value | Unit | Test Condition |
|---|---|---|---|
| Yield strength (ReH) | ≥420 | MPa | Transverse test, thickness ≤50 mm, room temperature |
| Tensile strength (Rm) | 530 – 680 | MPa | Transverse test, room temperature |
| Elongation after fracture (A5) | ≥18 | % | Gauge length 5.65√So, transverse, thickness ≤50 mm |
| Impact energy (KV) | ≥41 (longitudinal) | J | -40 °C, min. individual value may be 70% of specified average |
| Impact energy (KV) | ≥27 (transverse) | J | -40 °C, min. individual value may be 70% of specified average |
BV E420 Shipbuilding Steel Coil Fully Equivalent Material Standards and Substitute Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| International (ABS) | ABS Rules | EH40 / EH420 | Equivalent high-strength shipbuilding steel, -40 °C impact |
| International (DNV) | DNV Rules | VL E420 | DNV high-strength grade, same mechanical requirements |
| International (LR) | LR Rules | EH420 | Lloyd's Register grade, directly interchangeable |
| China | CCS Rules | E420 | China Classification Society equivalent grade |
| International (NK) | NK Rules | KE420 | Nippon Kaiji Kyokai equivalent high-strength grade |
| International (RINA) | RINA Rules | E420 | Italian ship classification society certified grade |
| South Korea | KR Rules | RE420 | Korean Register grade with similar properties |
| India | IRS Rules | E420 | Indian Register of Shipping equivalent |
BV E420 Shipbuilding Steel Coil Application Introduction
BV E420 steel is designed for critical load-bearing members in shipbuilding and offshore engineering. Its combination of high strength and excellent low-temperature toughness allows lighter structural designs without compromising safety.
- Welding procedures must follow approved practices, and preheating may be required for thicker sections.
- Forming and bending properties are suitable for cold and hot forming within specified limits.
- Ultrasonic testing and through-thickness properties can be specified for highly restrained joints.
Product Applications: Ship hull plate assemblies, Jack-up rig legs and spudcans, Deck beams and longitudinal stiffeners, Offshore module structural frames, Ice-strengthened vessel shells
Processed into products: Hull plates and shell plating, Bottom and side longitudinal stiffeners, Transverse bulkheads and web frames, Deck stringer plates, Crane pedestals and mast structures, Helideck supporting structures, Accommodation module frames
Application industries: Shipbuilding (hull, decks, bulkheads), Offshore oil and gas platforms, Renewable energy offshore structures (wind turbine foundations), Marine equipment and heavy machinery, Polar-class vessel construction
BV E420 Shipbuilding Steel Coil Similar / Alternative Materials with Comparable Performance
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10025-4 | S420ML | Structural steel with minimum yield 420 MPa, TMCP delivery, low temperature toughness; may require additional testing for marine service |
| Europe | EN 10025-6 | S420QL | Quenched and tempered steel with yield 420 MPa, suitable for offshore if certified |
| China | GB/T 712 | E420 | Chinese shipbuilding steel standard, equivalent to CCS E420 |
| Japan | JIS G 3106 | SM490YA | Welding structural steel, yield 365 MPa, lower strength but similar weldability; can be considered for less demanding structures |
| USA | ASTM A131 / A131M | Grade EH40 | Similar strength level, but minimum yield 390 MPa, close in toughness |
| International | BV Rules | E460 | Higher strength grade (460 MPa) from same BV series for weight reduction |
Notes:
BV E420 steel is normally supplied with 3.2 or 3.1 type certificates according to EN 10204, endorsed by Bureau Veritas surveyors. When ordering, the required delivery condition (e.g., TMCP, Normalized), thickness range, and any supplementary requirements such as Z-grade (through-thickness) testing must be clearly stated. Note: For thicknesses above 50 mm, chemical composition and mechanical property limits may be adjusted as per BV Rules, and should be confirmed at the time of enquiry and order.
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