AH40 Shipbuilding Steel Plate

⚙️ AH40 Steel Plate: Key Facts at a Glance

🔬 Grade Designation

A: Grade of quality, impact at 0°C |   H: High strength |  40: Yield strength grade, ≥390Pa Yield Strength

📊 Core Performance

• Strength: Yield ≥390 MPa
• Toughness: 0°C Impact Test

🌍 Primary Applications

High-strength hulls, decks, bulkheads of large commercial vessels (VLCCs, large container ships), critical offshore structures.

✅ Certifications & Standards

Complies with ABS, BV, CCS, DNV, etc. 9 major classification societies, EN 10204 3.1 certificate.

🔍 Quick Specs Summary: AH40 Steel Plate

  • Grade & Strength: AH40, 40 Class High Strength Steel
  • Yield Strength (ReH): ≥ 390 MPa
  • Impact Toughness: Tested at 0°C (32°F)
  • Key Property: Excellent Weldability and Formability
  • Primary Use: Critical hull structures, decks, bulkheads of large commercial vessels and offshore platforms
  • Service Environment: Demanding marine service, high-stress structural areas
  • Approvals: ABS, BV, CCS, DNV, LR, NK, RINA, KR, IRS
  • Delivery Condition: Normalized (N) or TMCP

AH40 shipbuilding steel plate is a high-strength hull structural steel designed for demanding marine applications where maximum load-bearing capacity with standard low-temperature toughness is required. It offers superior strength, excellent weldability, and certified impact performance for critical ship and offshore structures.

1. Product Definition and Classification

AH40 belongs to the 40 Class high-strength hull structural steel family with a minimum yield strength of 390 MPa. The prefix A indicates impact testing at 0°C in accordance with classification society rules. The letter H designates steel for hull structural applications. It represents the highest strength grade in the standard A-grade toughness series.

Applicable Classification Societies

  • ABS – American Bureau of Shipping (United States)
  • BV – Bureau Veritas (France)
  • CCS – China Classification Society (China)
  • DNV – Det Norske Veritas (Norway)
  • IRS – Indian Register of Shipping (India)
  • KR – Korean Register (South Korea)
  • LR – Lloyd's Register (United Kingdom)
  • NK – ClassNK (Japan)
  • RINA – Registro Italiano Navale (Italy)

Note: Listed in alphabetical order by society abbreviation for neutral reference.

2. Key Advantages

⚓ Maximum Marine Strength 🧱 Highest A-Grade Yield Strength ❄️ Reliable Low-Temperature Toughness 🔧 Optimized for Fabrication
Engineered for the most demanding hull sections and marine structures 390 MPa minimum yield strength for ultimate load-bearing and potential weight savings Maintains stable impact toughness at 0°C per classification requirements Superior weldability and formability for complex structural fabrication

3. Chemical Composition & Mechanical Properties

Chemical Composition (Typical, %)

C Si Mn P S Al
≤0.18 ≤0.50 0.90 – 1.60 ≤0.035 ≤0.035 ≥0.015

* Typical values according to classification society specifications. Actual limits may vary by approval.

Mechanical Properties

Thickness (mm) Yield Strength (MPa) Tensile Strength (MPa) Elongation (%) Impact Test Temperature
≤50 ≥390 510 – 650 ≥21 0°C

4. 40-Class Hull Steel: Toughness Grade Comparison

The following table compares different toughness grades within the 40 Class high-strength hull steel series. All grades share the same high minimum yield strength (≥390 MPa) but are designed for different service temperatures.

Steel Grade Impact Test Temperature Yield Strength (Min) Typical Application Environment
AH40 0°C ≥ 390 MPa Critical high-stress hull structures in general marine service
DH40 -20°C ≥ 390 MPa Large vessels and offshore structures operating in colder waters
EH40 -40°C ≥ 390 MPa High-strength offshore platforms and ice-class vessels requiring higher toughness
FH40 -60°C ≥ 390 MPa Extreme low-temperature, high-strength applications

5. A-Grade Hull Steel Series: Strength Progression

This table shows the strength progression within the A-Grade hull steel series (all grades impact tested at 0°C), illustrating available options for increasing load-bearing capacity while maintaining the same impact toughness level.

Performance Tier Steel Grade Yield Strength (Min) Impact Test Temperature Key Selection Insight
Tier 1: Baseline Strength AH32 ≥ 315 MPa 0°C Standard strength for general hull structures requiring 0°C impact toughness
Tier 2: Enhanced Strength AH36 ≥ 355 MPa 0°C Enhanced strength for higher load-bearing needs while maintaining 0°C impact toughness
Tier 3: High Strength AH40 ≥ 390 MPa 0°C Recommended choice for critical structural components requiring maximum strength with 0°C impact toughness

Choose Your Optimal Marine Steel Grade

Compare key specifications across our high-strength series. Varying parameters are highlighted for quick decision-making.

AH32

STANDARD
Yield Strength ≥315 MPa
Impact Temp 0°C
Key Feature Cost-Effective

AH36

ENHANCED
Yield Strength ≥355 MPa
Impact Temp 0°C
Key Feature Balanced Choice

DH40

LOW TEMP
Yield Strength ≥390 MPa
Impact Temp -20°C
Key Feature Cold Climate

AH40

CURRENT RECOMMENDATION
Yield Strength ≥390 MPa
Impact Temp 0°C
Key Feature Max Strength

6. Typical Applications

Critical hull structures of large commercial vessels (VLCCs, large container ships, Capesize bulk carriers)

High-stress decks, bulkheads, and longitudinal members in marine engineering

Primary structural components of offshore platforms and heavy-lift vessels

Areas requiring maximum strength-to-weight ratio in demanding marine service

7. Available Sizes & Supply Conditions

Thickness: 6 – 150 mm

Width: Up to 5,300 mm

Length: Up to 18,000 mm

Delivery Condition: Normalized (N) / Thermo-Mechanical Control Processed (TMCP)

Surface Treatment: As rolled, blasted, or primed (upon request)

8. Quality Control & Certification

Inspection & Quality Control

Chemical composition analysis

Tensile and elongation testing

Charpy V-notch impact testing at 0°C

Ultrasonic testing (UT) for internal quality

Third-party inspection available (SGS, BV, TUV, etc.)

Certification

Each shipment includes:

EN 10204 3.1 mill test certificate

Classification society approval certificate

Heat number traceability

Optional EN 10204 3.2 certificate (upon request)

9.Frequently Asked Questions

AH40 is primarily used for critical, high-stress hull structures, decks, bulkheads, and offshore marine components in large commercial vessels like VLCCs, large container ships, and Capesize bulk carriers where maximum strength is required.

The main difference is yield strength. AH36 has a minimum yield strength of ≥355 MPa, while AH40 offers ≥390 MPa. Both are impact tested at 0°C. AH40 provides approximately 10% higher load-bearing capacity, making it suitable for the most critical and highly stressed structural areas.

AH40 is impact tested at 0°C (32°F) in accordance with classification society requirements for general marine service conditions.

We provide EN 10204 3.1 mill test certificates along with classification society approval certificates for each shipment.

Yes, we can supply AH40 plates with certifications from major classification societies including ABS (American Bureau of Shipping), BV (Bureau Veritas), DNV (Det Norske Veritas), LR (Lloyd's Register), GL (Germanischer Lloyd), CCS (China Classification Society), NK (Nippon Kaiji Kyokai), KR (Korean Register), and RINA. We can work with your designated classification society to meet specific project requirements.

Yes, we can arrange third-party inspections from organizations like SGS, Bureau Veritas, TUV, or Lloyd's Register upon customer request.

Yes, we specialize in customized solutions. We can supply AH40 plates according to your specified dimensions, thicknesses, and classification society requirements. We also provide EN 10204 3.2 certificates upon request.

Delivery time for customized orders: Approximately 20 days for hot-rolled plates and 35-55 days for normalized plates, depending on specifications.

We offer flexible MOQ options. For hot-rolled plates, typical lead time is around 20 days. For normalized plates, expect 35-55 days depending on specifications and quantity. We do not have a mandatory requirement for the minimum order quantity of shipbuilding steel plates between 10-50mm, and we can basically provide them according to the quantity you need.

The price of AH40 steel plate fluctuates based on raw material costs, thickness, dimensions, purchase volume, and market conditions. For the most accurate and competitive real-time quotation, please contact our sales team with your specific requirements (grade, size, quantity, destination port, and any special certifications needed). We provide competitive pricing and respond within 24 hours.

We maintain a strategic inventory of high-strength grades. For AH40, availability depends on recent project orders. The inventory we maintain is often the portion exceeding specific customer orders. For accurate real-time stock levels of AH40, please contact our sales team or use our stock inquiry system.

Request Technical & Commercial Support

We supply classification-approved AH40 high-strength shipbuilding steel plate with full traceability, flexible inspection options, and coordinated logistics support.

📋 Certification & Quality

9 major classification societies

EN 10204 3.1 certificates

Third-party inspection available

⚙️ Custom Solutions

Custom dimensions & cutting

Various surface treatments

Flexible certification options

🚚 Logistics Support

Global shipping coordination

Documentation assistance

Technical support

Response Time: We typically respond to all inquiries within 24 hours