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.
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.
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 is one of the world’s most recognized classification societies, with strict controls over shipbuilding steels.
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.
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.
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.
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.
ABS requires steel mills to be officially approved and audited. Many globally recognized mills supplying through companies like sakysteel maintain updated ABS certification.
Lloyd’s Register (LR) applies similar but independently defined requirements.
LR requires strict chemical controls with limits similar to ABS but includes additional guidance on micro-alloying and residual elements.
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.
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.
LR adopts strict dimensional accuracy rules to ensure predictable fabrication performance.
LR requires plates to be marked with:
Mill name
Heat number
Grade (AH36, DH36, EH36)
Thickness and dimensions
LR approval stamp
DNV plays a major role in vessel construction and offshore energy projects.
DNV verifies composition through:
Heat analysis
Product analysis
Limits on carbon equivalent to ensure weldability
DNV mandates:
Yield strength consistency
Tensile strength within specific ranges
Minimum elongation for ductility
Higher uniformity is required for plates over a certain thickness.
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.
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.
DNV monitors the TMCP, normalization, and rolling processes to ensure microstructure stability.
Bureau Veritas (BV) provides certification widely accepted in Europe and international markets.
BV requires controlled levels of:
Carbon
Manganese
Silicon
Sulfur, phosphorus
Aluminum and micro-alloy elements
BV defines yield and tensile strength consistent with ASTM A131 and marine rules.
Mechanical requirements increase with thickness, grade, and rolling type.
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.
BV approves steel mills through:
Factory audits
Process control checks
Equipment inspection
Review of quality management systems
BV mandates EN 10204 3.2 or 3.1 certification depending on the project’s classification level.
Depending on plate thickness and application:
Level A
Level B
Level C
may be required to detect internal defects.
Plates must be free from:
Laminations
Cracks
Rust scale
Mechanical damage
All societies enforce strict:
Thickness tolerance
Width and length tolerance
Flatness tolerance
Every plate must include traceable:
Heat numbers
Material certificates
Test reports
Rolling records
This ensures compliance from steelmaking to final application.
Certified high-strength plates are used in:
Hull structures
Cargo decks
Bulk carriers, tankers, container vessels
Offshore platforms
Jack-up units
Floating production systems
Arctic and ice-class vessels
Marine cranes and lifting structures
Certification ensures long-term safety and reliability under extreme offshore conditions.
Regulatory Compliance
Certification is mandatory for flag-state approval.
Structural Integrity
Ensures steel meets performance expectations under load.
Weldability and Fabrication Reliability
Certified steels guarantee consistent welding behavior.
Global Acceptance
Vessels built with certified steel can operate internationally.
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.
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.