Why AH36, DH36, and EH36 Are Preferred for High-Strength Marine Applications

Steel Grade	Yield Strength (MPa)	Tensile Strength (MPa)	Impact Test Temperature	Application
AH36	355	490–620	0°C	General ship hulls and decks
DH36	355	490–620	-20°C	Offshore structures and cold seawater exposure
EH36	355	490–620	-40°C	Arctic conditions, deep-sea and polar vessels

Each grade provides a yield strength of 355 MPa and a tensile strength up to 620 MPa, ensuring excellent resistance to deformation and failure under heavy loading.

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Chemical Composition

The alloy composition of AH36, DH36, and EH36 is carefully engineered to balance strength, weldability, and corrosion resistance.

Typical Chemical Composition (%):

• Carbon (C): ≤ 0.18

• Manganese (Mn): 0.90–1.60

• Silicon (Si): 0.10–0.50

• Phosphorus (P): ≤ 0.035

• Sulfur (S): ≤ 0.035

• Niobium (Nb), Vanadium (V), Titanium (Ti): ≤ 0.10

The addition of micro-alloying elements like niobium and vanadium refines grain size, enhancing both toughness and strength. This controlled chemistry ensures the steels perform reliably even under the most severe maritime conditions.

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Key Mechanical Properties

All three grades are engineered to achieve the optimal combination of high yield strength, tensile strength, and ductility.

• Yield Strength: ≥ 355 MPa

• Tensile Strength: 490–620 MPa

• Elongation (in 50 mm): ≥ 21%

• Charpy Impact Energy:

  • AH36: Tested at 0°C

  • DH36: Tested at -20°C

  • EH36: Tested at -40°C

These properties make AH36, DH36, and EH36 the materials of choice for high-strength marine applications that must endure rough seas and extreme loads.

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Why AH36, DH36, and EH36 Are Preferred in the Marine Industry

1. Superior Strength-to-Weight Ratio

One of the primary advantages of these grades is their high strength combined with reduced weight. This allows shipbuilders to design lighter hulls without compromising safety. The result is improved fuel efficiency, greater payload capacity, and reduced emissions, aligning with modern maritime sustainability goals.

2. Excellent Low-Temperature Toughness

Ships operating in cold regions or polar waters require materials that retain toughness at sub-zero temperatures. DH36 and EH36, in particular, are tested for impact resistance at -20°C and -40°C, ensuring ductility and crack resistance even in icy environments.

3. Outstanding Corrosion Resistance

Saltwater and humidity accelerate corrosion, which can compromise a ship’s structural integrity. The chemical composition of AH36, DH36, and EH36 provides superior resistance to rust and oxidation, extending the service life of vessels and reducing maintenance costs.

4. Exceptional Weldability and Fabrication Ease

These steels exhibit excellent weldability without preheating, thanks to their low carbon equivalent value (CEV). They can be welded using SMAW, GMAW, or SAW techniques without compromising strength or structural performance. This makes them highly suitable for large-scale shipyard fabrication.

5. Resistance to Fatigue and Vibration

Marine vessels constantly face cyclic stresses from waves, cargo movement, and propulsion vibration. AH36, DH36, and EH36 steels possess superior fatigue strength, helping prevent micro-cracking and ensuring long-term durability in demanding service conditions.

6. Certified Quality and Global Standards Compliance

All three grades are approved by major classification societies:

• ABS (American Bureau of Shipping)

• Lloyd’s Register (LR)

• Det Norske Veritas (DNV)

• Bureau Veritas (BV)

• China Classification Society (CCS)

This ensures that steel plates supplied by sakysteel meet international safety and performance requirements for shipbuilding and offshore engineering.

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Applications in High-Strength Marine Structures

1. Ship Hull Construction

AH36 and DH36 plates are widely used in hull structures, decks, and frames of cargo vessels, tankers, and container ships. Their strength helps withstand wave pressure and impact loads without deformation.

2. Offshore Oil and Gas Platforms

EH36 steel, with its superior toughness at low temperatures, is ideal for offshore drilling rigs, floating production storage and offloading (FPSO) units, and subsea platforms that operate in harsh marine environments.

3. LNG and Polar Vessels

EH36 steel plates maintain excellent ductility in cryogenic conditions, making them suitable for liquefied natural gas (LNG) carriers, icebreakers, and Arctic expedition vessels.

4. Naval and Defense Applications

Due to their combination of strength, lightweight design, and impact resistance, these steels are extensively used in naval frigates, patrol ships, and defense vessels, ensuring superior combat readiness and maneuverability.

5. Offshore Wind and Marine Infrastructure

AH36, DH36, and EH36 are also used in offshore wind turbine foundations, mooring systems, and support frames, where they provide long-term resistance to fatigue and corrosion under dynamic ocean conditions.

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Processing and Fabrication Characteristics

1. Hot Rolling and TMCP (Thermo-Mechanical Controlled Processing):
   These steels are manufactured through TMCP, producing fine-grained microstructures that improve both strength and weldability.

2. Formability:
   The excellent ductility of AH36, DH36, and EH36 allows easy bending and forming without cracking or internal stress buildup.

3. Cutting and Machining:
   Compatible with plasma, oxy-fuel, and laser cutting techniques, ensuring precision and minimal heat distortion.

4. Surface Treatment:
   Plates can be supplied in shot-blasted, primed, or coated finishes to enhance corrosion resistance during transportation and storage.

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Testing and Certification

sakysteel ensures that every AH36, DH36, and EH36 plate undergoes rigorous testing before delivery:

• Chemical Composition Analysis (spectrometry)

• Tensile Strength and Elongation Tests

• Charpy V-Notch Impact Tests at specified temperatures

• Ultrasonic Testing (UT) for internal flaws

• Dimensional and Surface Inspection

All products are delivered with EN 10204 3.2 Mill Test Certificates, confirming compliance with international standards and classification requirements.

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Advantages of Choosing sakysteel Marine Steels

As a professional manufacturer and exporter of marine and offshore steels, sakysteel offers unmatched product quality and customer support:

• Full range of thickness (5–150 mm) and width (up to 3,500 mm)

• Certification from ABS, LR, DNV, BV, and CCS

• Customized dimensions and cutting services

• Fast delivery with seaworthy packaging

• Global supply network for shipyards and offshore projects

With sakysteel, clients can rely on high-quality AH36, DH36, and EH36 steel plates that meet the most demanding operational and safety requirements of the global marine industry.

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Future Trends in Marine Steel Applications

The future of shipbuilding and offshore engineering is being shaped by advancements in lightweight, energy-efficient, and sustainable materials. As vessels grow larger and more specialized, the demand for high-strength low-alloy steels like AH36, DH36, and EH36 continues to rise.

Emerging applications include:

• Hybrid propulsion vessels requiring weight-optimized hull materials

• Deep-sea mining and exploration platforms built for ultra-deep conditions

• Green shipping technologies, where corrosion-resistant steels reduce maintenance and emissions

Continuous innovation in steel processing — such as thermo-mechanical rolling and microalloying — ensures that these grades will remain at the forefront of marine engineering for decades to come.

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Conclusion

In modern shipbuilding and offshore engineering, the balance between strength, safety, and performance is critical. AH36, DH36, and EH36 steel plates have earned their reputation as the preferred materials for high-strength marine applications, offering exceptional toughness, corrosion resistance, and weldability across all environments.

From commercial cargo ships and oil tankers to polar research vessels and offshore platforms, these steels ensure reliability and durability where failure is not an option.

Supported by global certifications, precision manufacturing, and decades of metallurgical expertise, sakysteel continues to deliver AH36, DH36, and EH36 shipbuilding plates that set the standard for marine excellence. As the maritime world advances toward safer, cleaner, and more efficient operations, these high-strength steels remain the foundation for building the ships and offshore structures of the future.