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, 用途, 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 化学組成

DH36 meets strict international standards (例えば。, 腹筋, DNV, LR) with alloy additions that boost low-temperature toughness and corrosion resistance. Typical ranges are:

1.2 物理的特性

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

• 密度: 7.85 g/cm³ (consistent with structural steels, simplifying load and buoyancy calculations)
• 融点: 1,430 – 1,470°C (compatible with standard marine steel fabrication processes)
• 熱伝導率: 44 w/(M・k) 20°Cで (ensures even heating during welding, critical for cold-weather shipyard work)
• 熱膨張係数: 13.0 ×10⁻⁶/°C (20 – 100°C) | Prevents cracking from extreme temperature swings (例えば。, -40°C to 20°C in Arctic summers)
• 電気抵抗率: 0.18 μΩ·m (low enough for non-electrical components like hulls and bulkheads)

1.3 機械的特性

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

• 抗張力: 490 - 620 MPA (handles heavy cargo loads and icy wave impacts)
• 降伏強度: ≥ 355 MPA (meets the “36” rating—supports deepwater offshore platforms in cold seas)
• 硬度: 140 - 170 HB (ブリネル, soft enough for forming curved hulls, hard enough to resist ice scratches)
• 衝撃の靭性: ≥ 34 J at -60°C (the biggest advantage over other marine steels—avoids brittle failure in Arctic winters)
• 延性: 21 - 24% 伸長 (allows bending into complex hull shapes without cracking, even in cold temperatures)
• 疲労抵抗: 220 - 260 MPA (endures repeated wave and ice loads on offshore jackets and ship hulls)
• 骨折の靭性: 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: とても良い | 保護酸化物層を形成します; 適切なコーティングで, it resists saltwater and ice for 25+ 年
• 溶接性: 素晴らしい | Low carbon content means no preheating for plates up to 35mm thick (saves time in cold shipyards)
• 形成性: 強い | Can be hot rolled, コールドロール, or forged into curved hulls and jacket legs—even in low-temperature workshops
• タフネス: 例外的 | 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 (例えば。, 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 (例えば。, Russian Arctic supply ships use DH36 bulkheads—withstand flooding pressure in freezing seas)
• Decks: Supports heavy equipment and cargo (例えば。, Norwegian offshore supply vessels use DH36 decks—handle 60+ ton drilling machinery and ice accumulation)
• Superstructures: Above-deck command centers (例えば。, 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 (例えば。, Shell’s North Sea oil platforms use DH36 jacket legs—endure 12m waves and -20°C winters)
• Risers: Connects seabed wells to platforms (例えば。, BP’s Alaskan offshore risers use DH36—resist seawater corrosion and freezing temperatures)
• 海底パイプライン: Transports oil/gas in cold oceans (例えば。, 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 (例えば。, St. Petersburg Port in Russia uses DH36 quay walls—resist ice floes and saltwater for 30+ 年)
• Dolphins: Guides ships to docks (例えば。, Tromsø Port in Norway uses DH36 dolphins—handle ship collisions and freezing temperatures)
• Fenders: Absorbs ship impact (例えば。, 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 (例えば。, Nome, Alaska seawalls use DH36—survive ice-driven storm surges)
• Breakwaters: Reduces wave and ice energy (例えば。, Reykjavik Harbor in Iceland uses DH36 breakwaters—endure strong tides and ice)
• Jetties: Extends into cold seas for ship access (例えば。, 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. これがどのように生産されているかです, shaped, and finished.

3.1 スチール製造プロセス

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

• 基本的な酸素炉 (bof): The primary method—converts iron ore to steel by blowing oxygen through molten iron. Removes impurities (p, s) and adds high levels of Ni (for cold toughness) to meet DH36 specs. 大規模な生産に使用されます (90% of DH36).
• 電気弧炉 (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 (例えば。, 100mm+ plates for Arctic offshore jackets).

3.2 熱処理

Heat treatment optimizes DH36 for cold-water use:

• 正規化: Heats to 900 – 950°C, cools in air. Improves uniformity and ductility—used for hull plates and decks in cold regions.
• クエンチングと焼き戻し: Heats to 850 – 900°C, quenches in water, その後、気性になります 520 – 620°C. ブースト 強さ そして cold-temperature impact toughness—used for offshore jackets and Arctic ship hulls.
• アニーリング: Heats to 800 - 850°C, cools slowly. Reduces hardness for easier forming—used for curved hull sections in cold workshops.

3.3 プロセスの形成

DH36 is shaped to fit cold-marine design needs:

• ホットローリング: Heats to 1,100 – 1,200°C, rolls into plates (6 – 120mm thick). Used for hulls, ジャケット, and seawalls—hot forming avoids cracking in cold conditions.
• コールドローリング: Rolls at room temperature to make thin sheets (1 – 5mm thick). Used for superstructure panels—only for parts not exposed to extreme cold.
• 鍛造: Hammers or presses heated steel into complex shapes (例えば。, ship propeller shafts, jacket connectors—forged DH36 has enhanced toughness).
• スタンピング: Uses dies to cut or bend sheets into small components (例えば。, fender brackets, deck fasteners—stamped parts maintain cold resistance).

3.4 表面処理

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

• ショットブラスト: 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, パイプライン, 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.
• 亜鉛メッキ: Dips small parts (例えば。, ボルト, ブラケット) in molten zinc—prevents rust for 25+ years in cold, wet conditions.

4. ケーススタディ: DH36 Marine Steel in Action

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

4.1 海兵隊: Arctic LNG Carrier Hull

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

• 結果: Hulls have operated for 5 years with only 2% 腐食 (vs. 10% for standard marine steel), no ice-related cracks, and maintenance costs dropped by 40%.
• Key Factor: DH36’s -60°C impact toughness (38 j) そして 耐食性 endured Arctic ice and saltwater.

4.2 沖合: North Sea Wind Platform Jacket

場合: 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.

• 結果: 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 疲労抵抗 (240 MPA) そして cold-temperature toughness handled harsh North Sea conditions.

4.3 Coastal: Alaskan Seawall

場合: 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.

• 結果: Seawalls survived 4 major Arctic storms without damage, corrosion is minimal (1% 後 6 年), and they protect 500+ homes from flooding.
• Key Factor: DH36’s 降伏強度 (355 MPA) そして 衝撃の靭性 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. 以下の表は、重要な特性を比較しています:

キーテイクアウト:

• vs. other marine steels: DH36’s -60°C impact toughness is 70% better than AH36—worth the 25% cost premium for cold projects.
• vs. 炭素鋼 (A36): DH36 is 42% stronger and has 6x better cold toughness—avoids brittle failure in freezing seas.
• vs. ステンレス鋼 (316): DH36 is 73% 強くて 71% cheaper—needs coating, but a small tradeoff for large-scale cold projects.
• vs. アルミニウム (5083): DH36 is 69% 強くて 64% cheaper—far better for cold-water load-bearing parts.

6. Yigu Technology’s View on DH36 Marine Steel

Yiguテクノロジーで, 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 + エポキシコーティング (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.