ABS, LR, DNV, and BV Certification Requirements for AH36/DH36/EH36 Steel Plates

In global shipbuilding and offshore engineering, AH36, DH36, and EH36 steel plates represent some of the most critical high-strength materials used in hull fabrication, heavy-duty structures, and demanding marine environments. As the maritime industry evolves toward larger vessels, deeper offshore installations, and more stringent security requirements, steel used in these structures must comply not only with international standards but also with the certification rules of major classification societies. Among them, ABS, LR, DNV, and BV are the most influential and widely accepted in the shipbuilding world.

Meeting the technical requirements of these societies ensures structural safety, long-term durability, and global operational acceptance for ships and offshore units. Shipyards around the world rely on certified steel to guarantee that vessels meet compliance standards from the raw material stage through final assembly. Leading suppliers such as sakysteel provide materials that comply with the demanding rules of ABS, LR, DNV, and BV, enabling shipyards to operate with confidence and precision.

This article provides a comprehensive overview of the certification requirements for AH36, DH36, and EH36 steel plates, exploring chemical composition limits, mechanical properties, toughness criteria, dimensional controls, and factory approval processes across the four major classification societies.

Understanding the Role of Classification Societies

Classification societies establish safety rules, oversee testing procedures, and verify that ships and offshore platforms are built according to recognized engineering standards. For structural steels such as AH36, DH36, and EH36, these bodies define precise mechanical requirements, heat treatment conditions, and inspection procedures.

The four societies covered in this article include:

  • ABS American Bureau of Shipping

  • LR Lloyd’s Register

  • DNV Det Norske Veritas

  • BV Bureau Veritas

Compliance with these organizations enables steel plates to be used in global marine projects, ensuring universal recognition across shipyards, marine contractors, and regulatory authorities.

Overview of AH36, DH36, and EH36 Steel Grades

AH36, DH36, and EH36 are higher-strength shipbuilding steels defined by different toughness levels:

  • AH36 Normal strength impact at 0°C

  • DH36 Higher toughness, tested at -20°C

  • EH36 Even higher toughness levels, tested at -40°C

These grades provide excellent structural performance, weldability, and fatigue resistance for hull structures, decks, cranes, and offshore modules.

The classification societies review these materials not only by grade but also by precise chemical makeup, mechanical behavior, and production methods.

ABS Certification Requirements for AH36/DH36/EH36 Steel Plates

ABS is one of the world’s most recognized classification societies, with strict controls over shipbuilding steels.

1. Chemical Composition

ABS defines strict limits for:

  • Carbon content for weldability

  • Manganese and silicon for strength

  • Sulfur and phosphorus to reduce brittleness

  • Micro-alloying elements for grain refinement

Producers must provide full ladle analysis and verify compliance with ABS rules.

2. Mechanical Properties

ABS requires minimum values for:

  • Yield strength

  • Tensile strength

  • Elongation

DH36 and EH36 grades must meet higher requirements to ensure superior structural performance in low-temperature marine environments.

3. Impact Toughness Testing

ABS mandates Charpy V-Notch tests for:

  • AH36 at 0°C

  • DH36 at -20°C

  • EH36 at -40°C

The number of test specimens and acceptance criteria are clearly defined.

4. Heat Treatment and Delivery Condition

ABS may require steels to be:

  • As-rolled

  • Controlled-rolled

  • Normalized

  • Thermo-mechanically controlled processed (TMCP)

TMCP steels are preferred for higher strength and thinner plate designs.

5. Mill Approval

ABS requires steel mills to be officially approved and audited. Many globally recognized mills supplying through companies like sakysteel maintain updated ABS certification.

LR Certification Requirements for AH36/DH36/EH36 Steel Plates

Lloyd’s Register (LR) applies similar but independently defined requirements.

1. Compositional Controls

LR requires strict chemical controls with limits similar to ABS but includes additional guidance on micro-alloying and residual elements.

2. Tensile and Yield Strength

LR’s mechanical property tables define clear performance benchmarks:

  • AH36 minimum yield 355 MPa

  • DH36 and EH36 progressively higher toughness and performance

LR ensures uniform performance across plate thickness.

3. Charpy Impact Toughness

LR defines:

  • AH36 at 0°C

  • DH36 at -20°C

  • EH36 at -40°C

LR uses its own energy requirements, often slightly higher for thicker plates.

4. Dimensional and Flatness Tolerances

LR adopts strict dimensional accuracy rules to ensure predictable fabrication performance.

5. Certification and Marking

LR requires plates to be marked with:

  • Mill name

  • Heat number

  • Grade (AH36, DH36, EH36)

  • Thickness and dimensions

  • LR approval stamp

DNV Certification Requirements for AH36/DH36/EH36 Steel Plates

DNV plays a major role in vessel construction and offshore energy projects.

1. Chemical Composition Verification

DNV verifies composition through:

  • Heat analysis

  • Product analysis

  • Limits on carbon equivalent to ensure weldability

2. Mechanical Property Requirements

DNV mandates:

  • Yield strength consistency

  • Tensile strength within specific ranges

  • Minimum elongation for ductility

Higher uniformity is required for plates over a certain thickness.

3. Enhanced Toughness Criteria

DNV’s impact toughness requirements are well known for being rigorous:

  • AH36 at 0°C

  • DH36 at -20°C

  • EH36 at -40°C

For offshore structures, DNV may require supplementary testing.

4. Additional Testing for Offshore Projects

For platforms and subsea modules, DNV may mandate:

  • Drop-weight testing

  • Ultrasonic testing

  • Z-direction testing

These ensure plate reliability under fatigue and dynamic loading.

5. Manufacturing Process Control

DNV monitors the TMCP, normalization, and rolling processes to ensure microstructure stability.

BV Certification Requirements for AH36/DH36/EH36 Steel Plates

Bureau Veritas (BV) provides certification widely accepted in Europe and international markets.

1. Chemical Composition and Alloy Controls

BV requires controlled levels of:

  • Carbon

  • Manganese

  • Silicon

  • Sulfur, phosphorus

  • Aluminum and micro-alloy elements

2. Mechanical Property Standards

BV defines yield and tensile strength consistent with ASTM A131 and marine rules.

Mechanical requirements increase with thickness, grade, and rolling type.

3. Toughness and Impact Testing

BV requires:

  • AH36 at 0°C

  • DH36 at -20°C

  • EH36 at -40°C

Impact requirements must be met for three specimens to ensure consistency.

4. Manufacturing Approval and Inspection

BV approves steel mills through:

  • Factory audits

  • Process control checks

  • Equipment inspection

  • Review of quality management systems

5. Certification and Document Control

BV mandates EN 10204 3.2 or 3.1 certification depending on the project’s classification level.

Additional Requirements Common Across All Four Societies

1. Ultrasonic Testing

Depending on plate thickness and application:

  • Level A

  • Level B

  • Level C

may be required to detect internal defects.

2. Surface Quality Inspection

Plates must be free from:

  • Laminations

  • Cracks

  • Rust scale

  • Mechanical damage

3. Dimensional Accuracy

All societies enforce strict:

  • Thickness tolerance

  • Width and length tolerance

  • Flatness tolerance

4. Traceability and Documentation

Every plate must include traceable:

  • Heat numbers

  • Material certificates

  • Test reports

  • Rolling records

This ensures compliance from steelmaking to final application.

Applications of Certified AH36/DH36/EH36 Steel Plates

Certified high-strength plates are used in:

  1. Hull structures

  2. Cargo decks

  3. Bulk carriers, tankers, container vessels

  4. Offshore platforms

  5. Jack-up units

  6. Floating production systems

  7. Arctic and ice-class vessels

  8. Marine cranes and lifting structures

Certification ensures long-term safety and reliability under extreme offshore conditions.

Why Certification Matters to Shipyards and Marine Engineers

  1. Regulatory Compliance
    Certification is mandatory for flag-state approval.

  2. Structural Integrity
    Ensures steel meets performance expectations under load.

  3. Weldability and Fabrication Reliability
    Certified steels guarantee consistent welding behavior.

  4. Global Acceptance
    Vessels built with certified steel can operate internationally.

  5. Reduced Project Risk
    Lower likelihood of structural failure or unexpected repairs.

Suppliers such as sakysteel support shipyards with consistent certification, fast documentation delivery, and reliable testing compliance.

Conclusion

ABS, LR, DNV, and BV certification requirements for AH36, DH36, and EH36 steel plates are essential for ensuring structural strength, safety, and long-term operational reliability in marine and offshore environments. Each society maintains rigorous rules covering chemical composition, mechanical performance, toughness, inspection methods, and manufacturing approval. Compliance is not optional; it is the foundation of safe shipbuilding.

As the global marine industry continues to grow in complexity and scale, reliable certified materials from trusted suppliers remain the backbone of successful shipbuilding projects worldwide. Through strict quality systems and dependable certification management, producers like sakysteel provide shipyards with the confidence needed to meet international safety rules and deliver vessels capable of enduring the harshest working conditions.

Post time: Nov-14-2025