In the global marine and offshore industries, steel plates play a vital role in ensuring the structural integrity, safety, and longevity of vessels and platforms operating in some of the harshest environments on Earth. Among the most widely used materials are AH36, DH36, and EH36 steel plates, which belong to the high-strength structural steel category under ASTM A131 standards. These grades are engineered to withstand extreme loads, impacts, and corrosive marine conditions, making them indispensable for modern shipbuilding and offshore engineering projects.
At sakyalloy, we supply premium-quality AH36, DH36, and EH36 steel plates that meet international standards and deliver consistent performance across various demanding applications.
1. Overview of AH36, DH36, and EH36 Steel Grades
AH36, DH36, and EH36 are high-strength marine steels primarily used in the construction of ships and offshore structures. The main difference between these grades lies in their impact toughness requirements at different temperatures:
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AH36: Tested at 0°C (room temperature toughness)
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DH36: Tested at -20°C (low-temperature toughness)
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EH36: Tested at -40°C (extreme low-temperature toughness)
These grades share a similar chemical composition and mechanical properties, providing an optimal combination of yield strength (355 MPa minimum) and tensile strength (490–620 MPa), which ensures high load-bearing capacity and resistance to deformation.
2. Chemical and Mechanical Characteristics
The chemical composition of AH36, DH36, and EH36 steel plates typically includes:
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Carbon (C): ≤ 0.18%
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Manganese (Mn): 0.90–1.60%
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Silicon (Si): 0.10–0.50%
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Phosphorus (P): ≤ 0.035%
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Sulfur (S): ≤ 0.035%
These steels may also contain micro-alloying elements such as niobium, vanadium, and titanium to improve grain refinement and enhance toughness.
Mechanical properties:
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Yield Strength: ≥ 355 MPa
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Tensile Strength: 490–620 MPa
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Elongation: ≥ 21%
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Charpy V-notch Impact Test: 0°C (AH36), -20°C (DH36), -40°C (EH36)
This superior combination of strength and toughness allows these grades to maintain excellent weldability and formability during fabrication.
3. Applications in Shipbuilding Industry
a. Hull Construction
The hull is the backbone of any vessel, requiring materials that can endure compressive and bending stresses. AH36, DH36, and EH36 steel plates are used extensively for hull plating, deck structures, and keel sections.
These materials are ideal for:
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Container ships and cargo vessels
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Oil tankers and LNG carriers
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Naval and patrol ships
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Passenger and cruise liners
Their high tensile strength ensures superior performance under the stress of heavy loads and turbulent sea conditions.
b. Bulkheads and Superstructures
DH36 and EH36 plates are often selected for bulkheads and superstructures due to their ability to resist brittle fracture at low temperatures, which is especially crucial for Arctic navigation or polar-class ships.
c. Deck Plates and Reinforcements
The excellent weldability of these steels makes them suitable for deck reinforcement plates, frame structures, and other load-bearing parts that demand high fatigue resistance.
4. Offshore and Energy Applications
Beyond shipbuilding, AH36, DH36, and EH36 steel plates play a major role in offshore and marine engineering projects, such as:
a. Offshore Oil and Gas Platforms
These grades are used in jack-up rigs, semi-submersible platforms, and FPSOs (Floating Production Storage and Offloading units). Their resilience under impact and corrosion resistance in saltwater environments make them ideal for platform decks, legs, and support beams.
b. Wind Energy Structures
With the global shift towards renewable energy, offshore wind farms are expanding rapidly. EH36 steel plates, with superior toughness, are commonly used in wind tower foundations, monopiles, and transition pieces to withstand high wave and wind loads.
c. Subsea Equipment and Pipelines
In subsea applications, DH36 and EH36 grades are used for pressure vessels, pipe supports, and subsea structural frames, ensuring long-term durability against fatigue and corrosion.
5. Fabrication and Welding Performance
One of the key advantages of AH36, DH36, and EH36 steel plates is their excellent weldability and workability. They can be welded using common techniques such as:
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Shielded Metal Arc Welding (SMAW)
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Gas Metal Arc Welding (GMAW)
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Flux-Cored Arc Welding (FCAW)
Their low carbon equivalent value (CEV) ensures minimal risk of cracking during welding and high resistance to heat-affected zone brittleness. Post-weld heat treatment is rarely required, which makes fabrication faster and more cost-efficient.
At sakyalloy, all plates are subjected to ultrasonic testing, dimensional inspection, and mechanical property verification to ensure compliance with ASTM, ABS, LR, DNV, and BV standards.
6. Corrosion Resistance and Surface Treatments
Operating in marine environments exposes steel structures to constant attack from saltwater, humidity, and atmospheric pollutants. AH36, DH36, and EH36 steels exhibit good corrosion resistance due to controlled alloying and can be further protected through:
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Shot blasting and priming
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Zinc or epoxy coatings
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Cathodic protection systems
These surface treatments extend the service life of ships and offshore platforms, reducing maintenance costs and preventing structural degradation.
7. Classification Society Approvals
AH36, DH36, and EH36 steel plates are approved by major classification societies worldwide, including:
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ABS (American Bureau of Shipping)
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LR (Lloyd’s Register)
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BV (Bureau Veritas)
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DNV (Det Norske Veritas)
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GL, RINA, and NK
Such certifications guarantee that the plates meet the strict quality and performance criteria required for critical marine and offshore structures.
8. Advantages of Using AH36, DH36, and EH36
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High strength-to-weight ratio reduces the overall weight of the vessel, improving fuel efficiency.
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Excellent weldability simplifies fabrication and repair processes.
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Superior impact resistance ensures safety and performance even in freezing temperatures.
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Certified and traceable quality suitable for international ship classification standards.
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Cost-effective solution compared with alloy steels for similar performance levels.
9. Typical Clients and End Users
Industries that rely heavily on AH36, DH36, and EH36 plates include:
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Shipyards and marine fabricators
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Oil and gas engineering firms
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Offshore renewable energy developers
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Naval defense contractors
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Heavy fabrication workshops
These materials have been successfully deployed in projects across Asia, Europe, the Middle East, and the Americas.
10. Why Choose sakysteel for Marine Steel Solutions
sakysteel (a division of sakysteel) provides a full range of shipbuilding steels, including AH36, DH36, and EH36, sourced from reputable mills and available in customized dimensions, thicknesses, and surface conditions.
Our advantages include:
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Complete traceability with EN 10204 3.2 certificates
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On-time delivery and global logistics support
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Competitive pricing for bulk and project-based orders
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Expert technical support and after-sales service
Whether you are building a new vessel or fabricating offshore platforms, sakysteel ensures you receive marine-grade steel that meets or exceeds your engineering requirements.
Conclusion
The success of any shipbuilding or offshore project depends largely on the reliability of its structural materials. AH36, DH36, and EH36 steel plates have proven themselves to be the backbone of modern marine and offshore construction, providing unmatched strength, durability, and weldability.
Partnering with sakysteel means choosing a trusted supplier committed to quality, precision, and long-term performance. With our expertise and global reach, we are ready to support your next marine engineering project with materials that stand the test of the sea.
Post time: Nov-12-2025