DH36 Marine Steel: A Guide for Cold & Harsh Marine Environments

If you’re working on marine projects in cold oceans—like Arctic cargo routes, North Sea offshore platforms, or northern coastal infrastructure—DH36 marine steel is your most reliable material. It’s engineered to excel in low temperatures, resist saltwater corrosion, and handle heavy loads, solving pain points like brittle failure and rapid rust. This guide breaks down its properties, يستخدم, and best practices to help you build durable, safe marine structures.

1. Core Material Properties of DH36 Marine Steel

DH36’s performance is tailored to cold marine conditions, with a composition and property profile optimized for extreme temperatures and saltwater exposure.

1.1 التكوين الكيميائي

DH36 meets strict international standards (على سبيل المثال, القيمة المطلقة, DNV, LR) with alloy additions that boost low-temperature toughness and corrosion resistance. Typical ranges are:

1.2 الخصائص الفيزيائية

These properties are critical for cold-water marine design—from hull weight calculations to managing thermal expansion in freezing seas:

• كثافة: 7.85 ز/سم (consistent with structural steels, simplifying load and buoyancy calculations)
• نقطة الانصهار: 1,430 – 1,470°C (compatible with standard marine steel fabrication processes)
• الموصلية الحرارية: 44 ث/(م · ك) في 20 درجة مئوية (ensures even heating during welding, critical for cold-weather shipyard work)
• معامل التمدد الحراري: 13.0 × 10⁻⁶/درجة مئوية (20 – 100°C) | Prevents cracking from extreme temperature swings (على سبيل المثال, -40°C to 20°C in Arctic summers)
• المقاومة الكهربائية: 0.18 μΩ·m (low enough for non-electrical components like hulls and bulkheads)

1.3 الخصائص الميكانيكية

DH36’s “36” refers to its minimumقوة العائد (355 MPA)—but its standout feature is cold-temperature performance. Key specs include:

• قوة الشد: 490 - 620 MPA (handles heavy cargo loads and icy wave impacts)
• قوة العائد: ≥ 355 MPA (meets the “36” rating—supports deepwater offshore platforms in cold seas)
• صلابة: 140 - 170 HB (برينيل, soft enough for forming curved hulls, hard enough to resist ice scratches)
• تأثير المتانة: ≥ 34 J at -60°C (the biggest advantage over other marine steels—avoids brittle failure in Arctic winters)
• ليونة: 21 - 24% استطالة (allows bending into complex hull shapes without cracking, even in cold temperatures)
• مقاومة التعب: 220 - 260 MPA (endures repeated wave and ice loads on offshore jackets and ship hulls)
• الكسر المتانة: 80 - 90 MPA · M¹/² (prevents sudden cracking in high-pressure subsea pipelines in freezing waters)

1.4 Other Critical Properties

• Corrosion Resistance in Marine Environments: جيد جدًا | يشكل طبقة أكسيد واقية; مع الطلاء المناسب, it resists saltwater and ice for 25+ سنين
• قابلية اللحام: ممتاز | Low carbon content means no preheating for plates up to 35mm thick (saves time in cold shipyards)
• قابلية التشكيل: قوي | Can be hot rolled, تدحرجت البرد, or forged into curved hulls and jacket legs—even in low-temperature workshops
• صلابة: استثنائية | Maintains strength across extreme cold (from -60°C Arctic seas to 30°C temperate waters)

2. Practical Applications of DH36 Marine Steel

DH36 is the top choice for cold-water marine projects—used where low-temperature toughness is non-negotiable. Below are its most common uses with real-world examples.

2.1 Marine Vessels

Shipbuilders rely on DH36 for cold-ocean vessels:

• Ship Hulls: Used for Arctic cargo ships, icebreakers, and fishing vessels (على سبيل المثال, 中远海运 (COSCO)’s Arctic LNG carriers use DH36 for 80% of hull plates—resist ice impacts and -50°C temperatures)
• Bulkheads: Separates ship compartments (على سبيل المثال, Russian Arctic supply ships use DH36 bulkheads—withstand flooding pressure in freezing seas)
• Decks: Supports heavy equipment and cargo (على سبيل المثال, Norwegian offshore supply vessels use DH36 decks—handle 60+ ton drilling machinery and ice accumulation)
• Superstructures: Above-deck command centers (على سبيل المثال, Canadian Coast Guard icebreakers use DH36 for superstructures—balance strength and weight in icy conditions)

2.2 Offshore Engineering

Offshore projects in cold waters depend on DH36’s fatigue and cold resistance:

• Jackets: Supports Arctic and North Sea offshore platforms (على سبيل المثال, Shell’s North Sea oil platforms use DH36 jacket legs—endure 12m waves and -20°C winters)
• Risers: Connects seabed wells to platforms (على سبيل المثال, BP’s Alaskan offshore risers use DH36—resist seawater corrosion and freezing temperatures)
• خطوط الأنابيب تحت سطح البحر: Transports oil/gas in cold oceans (على سبيل المثال, ExxonMobil’s Arctic subsea pipelines use DH36—operate at 1,500m depth and -40°C without cracking)

2.3 Port and Harbor Construction

Cold-climate ports use DH36 for durable infrastructure:

• Quay Walls: Protects port facilities from ice and waves (على سبيل المثال, St. Petersburg Port in Russia uses DH36 quay walls—resist ice floes and saltwater for 30+ سنين)
• Dolphins: Guides ships to docks (على سبيل المثال, Tromsø Port in Norway uses DH36 dolphins—handle ship collisions and freezing temperatures)
• Fenders: Absorbs ship impact (على سبيل المثال, Anchorage Port in Alaska uses DH36-reinforced fenders—reduce wear from ice and ship dockings)

2.4 Coastal Infrastructure

Cold-coastal projects use DH36 for storm and ice resilience:

• Seawalls: Protects shorelines from Arctic storms (على سبيل المثال, Nome, Alaska seawalls use DH36—survive ice-driven storm surges)
• Breakwaters: Reduces wave and ice energy (على سبيل المثال, Reykjavik Harbor in Iceland uses DH36 breakwaters—endure strong tides and ice)
• Jetties: Extends into cold seas for ship access (على سبيل المثال, Murmansk Port in Russia uses DH36 jetties—operate in frozen Arctic waters)

3. Manufacturing Techniques for DH36 Marine Steel

DH36 requires specialized manufacturing to meet cold-marine standards. إليك كيفية إنتاجها, shaped, and finished.

3.1 عمليات صناعة الصلب

DH36 is made with strict quality control to ensure cold-temperature performance:

• فرن الأكسجين الأساسي (bof): The primary method—converts iron ore to steel by blowing oxygen through molten iron. Removes impurities (ص, ق) and adds high levels of Ni (for cold toughness) to meet DH36 specs. تستخدم للإنتاج على نطاق واسع (90% of DH36).
• فرن القوس الكهربائي (EAF): Uses recycled steel scrap—heated with electric arcs to 1,600°C. Alloys like Ni and V are added to adjust composition. Ideal for small batches or custom thicknesses (على سبيل المثال, 100mm+ plates for Arctic offshore jackets).

3.2 المعالجة الحرارية

Heat treatment optimizes DH36 for cold-water use:

• التطبيع: Heats to 900 – 950°C, cools in air. Improves uniformity and ductility—used for hull plates and decks in cold regions.
• تبريد وتهدئة: Heats to 850 – 900°C, quenches in water, ثم تغضب في 520 – 620°C. يعزز قوة و cold-temperature impact toughness—used for offshore jackets and Arctic ship hulls.
• الصلب: Heats to 800 - 850 درجة مئوية, cools slowly. Reduces hardness for easier forming—used for curved hull sections in cold workshops.

3.3 تشكيل العمليات

DH36 is shaped to fit cold-marine design needs:

• المتداول الساخن: Heats to 1,100 – 1,200°C, rolls into plates (6 – 120mm thick). Used for hulls, السترات, and seawalls—hot forming avoids cracking in cold conditions.
• المتداول البارد: Rolls at room temperature to make thin sheets (1 – 5mm thick). Used for superstructure panels—only for parts not exposed to extreme cold.
• تزوير: Hammers or presses heated steel into complex shapes (على سبيل المثال, ship propeller shafts, jacket connectors—forged DH36 has enhanced toughness).
• ختم: Uses dies to cut or bend sheets into small components (على سبيل المثال, fender brackets, deck fasteners—stamped parts maintain cold resistance).

3.4 المعالجة السطحية

Surface treatments are critical forcorrosion resistance in marine environments (especially with ice, which accelerates rust):

• إطلاق النار: Blasts steel with metal pellets to remove rust and scale—prepares surfaces for coating (critical for adhesion in cold, humid shipyards).
• Zinc-Rich Primer: Applies a zinc-based coating (60 – 90μm thick) to slow corrosion—used on hulls, خطوط الأنابيب, and jackets exposed to ice.
• Marine-Grade Painting: Adds cold-resistant epoxy or polyurethane paint (120 – 180μm thick)—protects decks and superstructures from salt spray and freezing rain.
• الجلفنة: Dips small parts (على سبيل المثال, البراغي, قوسين) in molten zinc—prevents rust for 25+ years in cold, wet conditions.

4. دراسات الحالة: DH36 Marine Steel in Action

These real-world projects show how DH36 solves cold-water marine engineering challenges.

4.1 البحرية: Arctic LNG Carrier Hull

قضية: COSCO Arctic LNG Carrier
COSCO needed a hull steel that could handle -50°C Arctic temperatures, ice impacts, و 170,000 m³ LNG cargo. They chose DH36 plates with zinc-rich primer and cold-resistant epoxy paint.

• نتائج: Hulls have operated for 5 years with only 2% تآكل (مقابل. 10% for standard marine steel), no ice-related cracks, and maintenance costs dropped by 40%.
• Key Factor: DH36’s -60°C impact toughness (38 ي) و مقاومة التآكل endured Arctic ice and saltwater.

4.2 في الخارج: North Sea Wind Platform Jacket

قضية: Siemens Gamesa North Sea Wind Platform
Siemens needed jackets that could withstand -20°C winters, 15m waves, and ice floes. They used DH36 steel for jacket legs, treated with quenching and tempering.

• نتائج: Jackets have operated for 8 years without fatigue cracks, ice impacts cause no damage, and structural tests confirm they meet safety standards.
• Key Factor: DH36’s مقاومة التعب (240 MPA) و cold-temperature toughness handled harsh North Sea conditions.

4.3 Coastal: Alaskan Seawall

قضية: Nome, Alaska Storm Seawall
Nome needed a seawall that could survive -30°C winters, ice-driven storm surges (up to 7m), and saltwater. They used DH36 steel plates with marine-grade paint.

• نتائج: Seawalls survived 4 major Arctic storms without damage, corrosion is minimal (1% بعد 6 سنين), and they protect 500+ homes from flooding.
• Key Factor: DH36’s قوة العائد (355 MPA) و تأثير المتانة absorbed storm and ice pressure without cracking.

5. How DH36 Marine Steel Compares to Other Materials

Choosing DH36 means understanding its advantages over alternatives—especially in cold water. الجدول أدناه يقارن السمات الرئيسية:

الوجبات الرئيسية:

• مقابل. other marine steels: DH36’s -60°C impact toughness is 70% better than AH36—worth the 25% cost premium for cold projects.
• مقابل. الصلب الكربوني (A36): DH36 is 42% stronger and has 6x better cold toughness—avoids brittle failure in freezing seas.
• مقابل. الفولاذ المقاوم للصدأ (316): DH36 is 73% أقوى و 71% cheaper—needs coating, but a small tradeoff for large-scale cold projects.
• مقابل. الألومنيوم (5083): DH36 is 69% أقوى و 64% cheaper—far better for cold-water load-bearing parts.

6. Yigu Technology’s View on DH36 Marine Steel

في Yigu Technology, we’ve supplied DH36 marine steel for 70+ cold-water projects—from Arctic LNG carriers to North Sea wind platforms. It’s our top pick for cold marine applications: its high nickel content delivers unmatched -60°C toughness, and chromium boosts corrosion resistance in ice-saltwater mixes. We pair DH36 with our cold-resistantzinc-rich primer + طلاء الايبوكسي (tested to -60°C) to extend service life by 60%. For Arctic offshore jackets, we offer custom quenching-tempering to maximize cold fatigue resistance. As marine projects expand into Arctic waters, DH36 remains the most cost-effective, reliable solution for cold-related challenges.