ABS Grade AH40 Shipbuilding Steel Coil
ABS Grade AH40 Shipbuilding Steel Coil - High Strength Hull Structural Steel
ABS Grade AH40 is a high strength shipbuilding steel with minimum yield strength of 390 MPa, suitable for hull structures and marine applications.
Hot rolling, normalizing, TMCP, welding, forming, cutting, bending
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ABS Grade AH40 Shipbuilding Steel Coil Introduction
ABS Grade AH40 is a high-strength hull structural steel governed by the American Bureau of Shipping (ABS) Rules for Materials and Welding. It belongs to the AH40 category, offering a minimum yield strength of 390 MPa (40 kgf/mm²) and excellent toughness at 0°C. This steel is designed for critical ship and offshore structures, exhibiting good weldability, formability, and resistance to brittle fracture. It is typically supplied as coils or plates in various thicknesses, delivered in as-rolled, normalized, or thermomechanically controlled processed (TMCP) condition. The steel meets strict chemical composition limits, including carbon equivalent Ceq ≤ 0.40%, to ensure reliable welding performance.
- High strength: minimum yield 390 MPa
- Good low-temperature toughness (0°C impact test)
- Excellent weldability with controlled Ceq
- Suitable for primary structural members of ships, offshore platforms, and marine equipment
ABS Grade AH40 Shipbuilding Steel Coil Chemical Composition
The chemical composition of ABS AH40 steel is controlled according to IACS UR W11 and ABS rules. The table shows maximum limits for ladle analysis, with elements such as Nb, V, Ti added for grain refinement. Carbon equivalent (Ceq) ≤ 0.40% is mandatory to ensure weldability. Residual elements like Cu, Cr, Ni, Mo are limited. In addition, fully killed with fine grain practice (acid soluble aluminum ≥ 0.015%) is required.
| Element | Standard Value | Remarks |
|---|---|---|
| C | ≤ 0.18 | Max |
| Mn | 0.90 - 1.60 | Range |
| Si | 0.10 - 0.50 | Range |
| P | ≤ 0.035 | Max |
| S | ≤ 0.035 | Max |
| Als (acid soluble) | ≥ 0.015 | Min, if killed |
| Nb | ≤ 0.05 | Max |
| V | ≤ 0.10 | Max |
| Ti | ≤ 0.02 | Max |
| Cu | ≤ 0.35 | Max |
| Cr | ≤ 0.20 | Max |
| Ni | ≤ 0.40 | Max |
| Mo | ≤ 0.08 | Max |
| N | ≤ 0.009 | Max, if not Al treated |
| Ceq (C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15) | ≤ 0.40 | Max |
ABS Grade AH40 Shipbuilding Steel Coil Thermal and Electrical Physical Properties
The following physical properties are typical for carbon-manganese structural steels and are not mandated by ABS standards but are representative for AH40. Values are at room temperature unless otherwise specified. Density, elastic modulus, thermal expansion, and thermal conductivity are important for design calculations. Variations may occur due to manufacturing process and exact chemistry.
| Property | Standard Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ (7850 kg/m³) | 20°C |
| Elastic Modulus (E) | 210 | GPa | 20°C |
| Shear Modulus (G) | 80 | GPa | 20°C |
| Poisson's Ratio (ν) | 0.3 | -- | 20°C |
| Thermal Expansion Coefficient (α) | 12.0 (20-100°C) | 10^-6/K | Average |
| Thermal Conductivity (λ) | ~50 | W/(m·K) | 20°C |
| Specific Heat Capacity (c) | ~460 | J/(kg·K) | 20°C |
| Electrical Resistivity (ρ_e) | ~0.2 | μΩ·m | 20°C |
ABS Grade AH40 Shipbuilding Steel Coil Mechanical Properties
Mechanical properties are tested according to ABS rules. Tensile tests are performed on transverse specimens, and impact tests (Charpy V-notch) are carried out at 0°C for grade A (hence AH40). Yield strength, tensile strength, elongation, and impact energy are the primary requirements. Bending tests may be specified for thickness verification. Values apply for thicknesses up to approximately 100 mm; for thicker plates, slight adjustments may apply.
| Property | Standard Value | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) | ≥ 390 | MPa | Transverse, thickness ≤ 100 mm |
| Tensile Strength (Rm) | 510 - 650 | MPa | Transverse, thickness ≤ 100 mm |
| Elongation (A, 5.65√So) | ≥ 20 | % | Transverse, thickness ≤ 100 mm |
| Charpy Impact Energy (KV) | ≥ 34 (average), ≥ 24 (individual) | J | Transverse, 0°C |
| Bend Test (Mandrel Diameter) | 3t (t ≤ 25 mm), 4t (25 < t ≤ 50 mm), 5t (t > 50 mm) | -- | 180°, no cracks |
ABS Grade AH40 Shipbuilding Steel Coil Equivalent Material Standards and Replaceable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| International | LR Rules | LR AH40 | Lloyd's Register equivalent |
| Norway | DNV Rules | DNV AH40 | DNV classification society |
| France | BV Rules | BV AH40 | Bureau Veritas equivalent |
| Germany | GL Rules | GL AH40 | Germanischer Lloyd (now DNV GL) |
| Japan | NK Rules | NK AH40 | Nippon Kaiji Kyokai (ClassNK) |
| South Korea | KR Rules | KR AH40 | Korean Register |
| China | CCS Rules | CCS AH40 | China Classification Society |
| Italy | RINA Rules | RINA AH40 | Registro Italiano Navale |
ABS Grade AH40 Shipbuilding Steel Coil Application Introduction
ABS AH40 steel is extensively used in the marine industry for primary structural components where high strength and moderate low-temperature toughness are required. It is suitable for cold forming, welding, and cutting. Below are typical industries, products, and components.
Product Applications: Bulk carriers, tankers, container ships hull shells and decks, Offshore platform decks, modules, and legs, Ship bottom and side shells, longitudinal and transverse bulkheads, Hatch covers, rudder horns, stern frames, Coil-fed applications in ship panels and stiffeners
Processed into products: Longitudinal stiffeners, Transverse web frames, Deck plates, Bottom plates, Keel plates, Bilge keels, Stringer plates, Bulkhead plates
Application industries: Shipbuilding, Offshore Oil & Gas, Marine Engineering, Port and Harbor Equipment, Military Naval Vessels
ABS Grade AH40 Shipbuilding Steel Coil Similar / Substitute Material Recommendations
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10025-3 | S420ML (TMCP) | Yield ~420 MPa, low temperature toughness, not ship-specific but similar strength |
| USA | ASTM A572 | Grade 60 (Type 1) | High strength low alloy, yield 415 MPa (60 ksi), but may lack impact test at 0°C unless specified |
| Japan | JIS G3106 | SM490A | Welding structural steel, yield 325 MPa, lower strength; SM490YA closer |
| China | GB/T 712 | AH40 | Direct equivalent to ABS AH40, same requirements |
| Russia | GOST 5521 | A40S | Shipbuilding steel, analog close |
Notes:
The data provided is based on ABS Rules for Materials and Welding, IACS UR W11, and typical values from steel producers. For critical applications, always refer to the latest ABS rules and mill certificates. Additional testing such as ultrasonic testing, fracture toughness (CTOD), or through-thickness properties may be required by the purchaser. Delivery conditions (N, TMCP) must be agreed between the customer and supplier. This steel, as a coil, can be further processed by cutting, leveling, and shot blasting before use.
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