In the demanding world of shipbuilding and offshore engineering, materials are constantly challenged by extreme environments, including low temperatures, high pressure, and continuous stress from waves and mechanical loads. The structural integrity of ships and offshore platforms depends not only on high tensile strength but also on a critical property known as impact toughness — the ability of steel to absorb energy and resist brittle fracture at low temperatures.
Among the most trusted marine steels, DH36 and EH36 are renowned for their low-temperature impact resistance, setting the standard for performance and safety in harsh marine environments. These steels are specifically engineered to maintain ductility and toughness even when exposed to sub-zero temperatures, ensuring that vessels and offshore structures can operate safely in cold seas and Arctic conditions.
As a globally certified supplier of marine steels, sakysteel provides DH36 and EH36 shipbuilding plates that fully comply with international classification standards such as ABS, DNV, LR, BV, and CCS, offering unmatched reliability and toughness in low-temperature service.
Understanding DH36 and EH36 Steel Grades
Both DH36 and EH36 are part of the ASTM A131 / ABS high-strength structural steel series, specifically designed for ship hulls, decks, and offshore platforms that operate in cold environments. These steels share the same mechanical strength but differ in their impact toughness and test temperature ratings.
| Steel Grade | Yield Strength (MPa) | Tensile Strength (MPa) | Charpy Impact Test Temperature | Typical Application |
|---|---|---|---|---|
| DH36 | 355 | 490–620 | -20°C | Offshore platforms, cold-water ship hulls |
| EH36 | 355 | 490–620 | -40°C | Arctic vessels, LNG carriers, and polar structures |
The main difference lies in the temperature at which each grade retains its toughness — a crucial factor in preventing structural failure during cold exposure.
The Importance of Low-Temperature Impact Resistance
When steel structures are exposed to low temperatures, their ability to deform plastically decreases. As the temperature drops, steels can transition from a ductile state to a brittle state, where cracks can propagate suddenly and catastrophically under impact or stress. This phenomenon, known as the ductile-to-brittle transition, is one of the biggest concerns in marine design.
Low-temperature impact resistance measures how well a steel can absorb impact energy and resist fracture under these conditions. The higher the impact energy value at a given temperature, the tougher and safer the material is.
DH36 and EH36 steels are engineered to maintain high impact energy absorption well below freezing temperatures, ensuring that they can withstand:
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Repeated wave and vibration stresses
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Sudden collisions or grounding events
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Mechanical shocks from cargo handling
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Rapid temperature fluctuations during operation
In short, low-temperature toughness defines the safety margin of ships and offshore platforms operating in cold and polar regions.
Microstructure and Alloy Design Behind Toughness
The superior impact toughness of DH36 and EH36 steels originates from their controlled chemical composition and thermo-mechanical processing (TMCP).
Typical Chemical Composition (%):
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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
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Niobium (Nb), Vanadium (V), Titanium (Ti): ≤ 0.10
Microalloying with Nb, V, and Ti refines the grain structure, while controlled rolling and accelerated cooling ensure a fine, uniform ferrite-pearlite microstructure. This refined grain structure minimizes crack propagation and enhances toughness at sub-zero temperatures.
Charpy Impact Test: The Benchmark of Quality
The Charpy V-notch (CVN) impact test is the standard method used to evaluate low-temperature toughness in DH36 and EH36 steel plates. The test measures the energy absorbed (in Joules) when a notched specimen is struck by a pendulum hammer at a specified temperature.
Standard Requirements:
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DH36: Tested at -20°C, minimum absorbed energy of 34 Joules
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EH36: Tested at -40°C, minimum absorbed energy of 34 Joules
This testing ensures that:
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DH36 remains ductile in cold ocean environments
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EH36 provides superior safety in Arctic or cryogenic service conditions
The higher impact resistance of EH36 gives it an edge in ice-class ships, LNG carriers, and deep-sea installations, where extreme cold and high stress demand the highest material performance.
Mechanical Properties Comparison
| Property | DH36 | EH36 |
|---|---|---|
| Yield Strength (MPa) | 355 | 355 |
| Tensile Strength (MPa) | 490–620 | 490–620 |
| Elongation (%) | ≥ 21 | ≥ 21 |
| Impact Test Temperature | -20°C | -40°C |
| Minimum Impact Energy (J) | 34 | 34+ |
Both grades provide the same high yield and tensile strength, but EH36 maintains its toughness even at much lower temperatures — a defining factor for its use in polar or cryogenic environments.
Applications of DH36 and EH36 Steels
1. Offshore Platforms and Structures
DH36 and EH36 are widely used in offshore drilling platforms, floating production storage and offloading (FPSO) units, and subsea structures, where temperature drops and saltwater corrosion require high toughness and resistance to crack propagation.
2. Shipbuilding and Hull Construction
The hull of a ship must resist wave impact, compression, and torsion without fracturing. DH36 and EH36 steels ensure the hull remains strong and flexible, even in cold climates such as the North Atlantic and Arctic waters.
3. LNG Carriers and Cryogenic Equipment
EH36 is the preferred material for LNG storage tanks and transport vessels, where temperatures can reach -163°C. Its ability to maintain ductility at extremely low temperatures ensures containment integrity and safety.
4. Polar and Ice-Class Vessels
Icebreakers and polar research ships rely on EH36 for their outer hulls and decks, as it resists brittle fracture upon impact with ice or floating debris.
5. Offshore Wind Energy Foundations
As offshore wind farms expand into colder seas, EH36 steel is used in turbine towers and monopile foundations, ensuring reliable performance in sub-zero marine conditions.
Key Advantages of Low-Temperature Steels
1. Safety and Structural Integrity
Low-temperature impact resistance prevents sudden brittle failures, ensuring the safety of crew, cargo, and marine infrastructure even under unexpected loading or environmental stress.
2. Extended Service Life
The refined microstructure of DH36 and EH36 resists fatigue cracking, leading to longer operational lifespans for ships and offshore facilities.
3. Reduced Maintenance Costs
High toughness and corrosion resistance minimize the frequency of repairs caused by cracking, wear, or environmental damage.
4. High Strength-to-Weight Ratio
Both steels allow for lighter structural designs, improving vessel efficiency and reducing fuel consumption while maintaining superior strength.
5. Compliance with International Standards
All DH36 and EH36 steels supplied by sakysteel meet international classification society requirements, guaranteeing consistency and reliability in global marine projects.
Testing and Certification
Every batch of sakysteel DH36 and EH36 plates undergoes comprehensive testing and certification:
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Tensile and Yield Strength Tests
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Charpy Impact Tests at -20°C and -40°C
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Ultrasonic Testing (UT) for internal defects
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Spectrometer Chemical Analysis
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Dimensional Accuracy and Surface Finish Inspection
sakysteel provides EN 10204 3.1/3.2 Mill Test Certificates, ensuring full traceability and compliance with ABS, DNV, LR, BV, and CCS standards.
Manufacturing and Fabrication Excellence
sakysteel uses advanced thermo-mechanical controlled processing (TMCP) and precision rolling to produce DH36 and EH36 plates with fine-grain structures and superior surface quality.
Key Features:
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Plate thickness range: 5–150 mm
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Width up to 3,500 mm
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Length up to 12,000 mm
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Custom cutting and beveling services
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Surface conditions: shot-blasted, primed, or coated
These features ensure consistent performance during fabrication, welding, and assembly in shipyards and offshore facilities.
Why Low-Temperature Toughness Matters for Safety
Marine disasters caused by brittle fracture in cold environments have historically underscored the importance of impact toughness. Without adequate low-temperature resistance, steel structures can fail suddenly under stress — even without excessive load.
By maintaining high Charpy impact values at sub-zero temperatures, DH36 and EH36 steels prevent catastrophic failure, protect lives, and ensure compliance with modern safety regulations in marine and offshore construction.
In essence, low-temperature impact resistance defines the quality, reliability, and safety margin of DH36 and EH36 steel grades.
Why Choose sakysteel for DH36 and EH36 Plates
As a trusted global supplier, sakysteel provides high-quality DH36 and EH36 marine steel plates that combine mechanical strength with excellent low-temperature toughness. Our advanced production processes and quality management systems ensure that each plate meets international specifications and delivers consistent performance.
sakysteel advantages include:
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Certifications from ABS, LR, DNV, BV, and CCS
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Advanced TMCP and heat treatment technology
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Rapid delivery and worldwide logistics
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Third-party inspections (SGS, TUV, BV)
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Competitive pricing and reliable after-sales service
Through innovation and precision, sakysteel continues to supply steels that power the global shipbuilding, offshore energy, and polar exploration industries.
Future Outlook: Materials for Extreme Environments
As exploration moves toward colder oceans and deeper waters, the demand for low-temperature high-toughness steels will continue to grow. Advanced materials like DH36 and EH36 will remain essential for the next generation of energy-efficient, Arctic-capable, and environmentally sustainable marine vessels.
Future developments in microalloying and thermomechanical processing will further enhance their impact resistance, weldability, and corrosion protection, supporting the marine industry’s evolution toward safer and more sustainable operations.
Conclusion
The low-temperature impact resistance of DH36 and EH36 steels is the defining factor that ensures their superior performance in cold and harsh marine environments. Their ability to absorb energy and resist brittle fracture at -20°C and -40°C makes them indispensable for offshore platforms, polar vessels, LNG carriers, and deep-sea structures.
With exceptional mechanical strength, weldability, and toughness, DH36 and EH36 not only enhance safety and performance but also extend the operational lifespan of ships and offshore installations.
Backed by global certifications and precision manufacturing, sakysteel continues to deliver DH36 and EH36 steel plates that uphold the highest standards of marine safety, durability, and reliability — setting a new benchmark for quality in the global shipbuilding industry.
Post time: Nov-11-2025