RINA A40 Shipbuilding Steel Coil
RINA A40 Shipbuilding Steel Coil - High Strength Marine-Grade Structural Steel
Comprehensive material data for RINA A40 shipbuilding steel coil, including chemical composition, mechanical and physical properties, international equivalents, and application guidance.
Welding, cold forming, bending, machining, flame cutting
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RINA A40 Shipbuilding Steel Coil Introduction
RINA A40 is a high-strength shipbuilding structural steel grade certified by the Registro Italiano Navale (RINA). It belongs to the high-strength hull structural steel family, equivalent to AH40 under common IACS classification. The steel offers a minimum yield strength of 390 MPa and excellent toughness, weldability, and corrosion resistance in marine environments. Its fine-grained microstructure, achieved through controlled rolling or normalizing, ensures reliable performance at low temperatures. Typical delivery condition is normalized or thermo-mechanically controlled processed (TMCP) as coils or plates. This grade is widely used for critical ship components such as main decks, bottom shells, and bulkheads.
RINA A40 Shipbuilding Steel Coil Chemical Composition
The ladle analysis shall comply with the limits below. Additional microalloying elements such as Nb, V, Ti may be present to ensure grain refinement and strength. Residual elements (Cr, Ni, Mo, Cu) are restricted but often allowed up to certain limits unless Cr+Ni+Mo+Cu exceeds a specified total.
- Carbon equivalent (CEV) guaranteed as per specification when required for welding.
- Fine-grain practice is mandatory; aluminium or other grain-refining elements are used.
| Element | Standard Value (max, unless range specified) | Remarks |
|---|---|---|
| C (Carbon) | 0.18% | Ladle analysis |
| Si (Silicon) | 0.10 – 0.50% | |
| Mn (Manganese) | 0.90 – 1.60% | |
| P (Phosphorus) | 0.035% | Max value |
| S (Sulfur) | 0.035% | Max value |
| Al (Aluminium, acid-soluble) | ≥ 0.015% | Grain refinement |
| Nb (Niobium) | 0.02 – 0.05% | Optional but typical |
| V (Vanadium) | 0.05 – 0.10% | Optional but typical |
| Ti (Titanium) | ≤ 0.02% | Optional |
| Cr (Chromium) | ≤ 0.20% | Residual |
| Ni (Nickel) | ≤ 0.40% | Residual |
| Mo (Molybdenum) | ≤ 0.08% | Residual |
| Cu (Copper) | ≤ 0.35% | Residual |
RINA A40 Shipbuilding Steel Coil Thermal and Electrical Physical Properties
Representative values for low-carbon structural steel at room temperature (unless indicated). The data are intended for engineering calculations and modelling.
- Properties are nearly isotropic.
- Thermal conductivity decreases with increasing temperature.
- Density may vary slightly with alloy content.
| Property | Typical Value | Unit | Condition / Test |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | At 20°C |
| Elastic Modulus (E) | 205 – 210 | GPa | Room temperature |
| Shear Modulus (G) | 79 – 81 | GPa | Room temperature |
| Poisson's Ratio (ν) | 0.28 – 0.30 | - | Room temperature |
| Thermal Expansion Coefficient (α) | 11.7 | ×10⁻⁶/°C | 20 – 100°C |
| Thermal Conductivity (λ) | 51.9 | W/(m·°C) | At 20°C |
| Specific Heat Capacity (c) | 486 | J/(kg·°C) | At 20°C |
| Electrical Resistivity (ρ_e) | 0.15 – 0.20 | μΩ·m | At 20°C |
RINA A40 Shipbuilding Steel Coil Mechanical Properties
Minimum requirements at ambient temperature according to RINA rules for A40 grade (thickness ≤50 mm). For greater thicknesses, agreed values may slightly differ. Impact tests at 0°C (grade A). Bend test mandrel diameter depends on specimen orientation and thickness. All values are for longitudinal test pieces unless stated otherwise.
| Property | Standard Value | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) | ≥ 390 | MPa | t ≤ 50 mm |
| Yield Strength (ReH) | ≥ 370 | MPa | 50 < t ≤ 70 mm |
| Yield Strength (ReH) | ≥ 360 | MPa | 70 < t ≤ 100 mm |
| Tensile Strength (Rm) | 510 – 660 | MPa | t ≤ 100 mm |
| Elongation (A) | ≥ 20 | % | Gauge length 5.65√So |
| Elongation (A) | ≥ 18 | % | For thickness >50 mm |
| Bend Test (Mandrel Diameter) | 3t (≤180°) | - | Transverse, t≤25 mm |
| Bend Test (Mandrel Diameter) | 4t (≤180°) | - | Transverse, t>25 mm |
| Impact Energy (KV) at 0°C | ≥ 34 (long.) / ≥ 24 (trans.) | J | Charpy V, 0°C |
| Impact Energy (KV) at -20°C | ≥ 28 (long.) | J | For reference only (E-grade) |
RINA A40 Shipbuilding Steel Coil Fully Equivalent Material Standards and Replaceable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| International (IACS) | UR W11 | AH40 | Normalized or TMCP; impact at 0°C |
| USA | ABS Rules | AH40 | American Bureau of Shipping |
| Norway/Germany | DNV Rules | AH40 / NV A40 | Close equivalent |
| France | BV Rules | AH40 | Bureau Veritas |
| UK | LR Rules | AH40 | Lloyd's Register |
| China | CCS Rules | AH40 | China Classification Society |
| Korea | KR Rules | AH40 | Korean Register |
| Japan | NK Rules | AH40 | Nippon Kaiji Kyokai |
| Europe | EN 10025-4 | S420M / S420ML | TMCP rolling, similar strength and impact properties |
RINA A40 Shipbuilding Steel Coil Application Introduction
RINA A40 steel is designed for high-load-bearing ship structures and marine components. Its combination of high strength, good weldability, and guaranteed toughness makes it suitable for:
- Main decks and shell plating of large ships
- Offshore platform deck structures
- Bottom and side longitudinals
- Heavy-lift crane booms for marine service
Product Applications: Ship hulls (tankers, bulk carriers, container ships), Offshore topside modules, Jack-up rig legs, Barge decks, Structural reinforcements
Processed into products: Deck plates and stiffened panels, Bottom shell and bilge plates, Web frames and girders, Bulkhead plates, Hatch coaming, Crane pedestal structures
Application industries: Marine & Shipbuilding, Offshore Oil & Gas, Port & Heavy Machinery, Renewable Energy (Offshore Wind)
RINA A40 Shipbuilding Steel Coil Similar Material Alternatives with Close Properties
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| International | IACS | DH40 / EH40 | Lower service temperature capability, otherwise same strength |
| Europe | EN 10025-3 | S420N / S420NL | Normalized, similar strength, suitable for offshore |
| USA | ASTM A131 | EH40 | Higher toughness, but equivalent in strength |
| Russia | GOST R 52927 | 42CrMo4 type (not identical) | Different chemistry, only approximate |
| International | IACS | AH36 | Lower yield strength (355 MPa), used for less demanding structures |
Notes:
Weldability: The steel can be welded by all common arc processes. Preheating may be required for thick sections (>30 mm). The carbon equivalent (CEV) should be provided by the steel manufacturer to assess cold cracking sensitivity. Ultrasonic testing is often specified for critical applications in accordance with applicable classification society rules.
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