Steel Plates for Offshore Structures
Product Application: Boiler drums, superheater tube sheets, economizers, furnace liners, storage tanks, reactors, heat exchangers, separators, low-temperature storage tanks, hydroprocessing reactors, nuclear power auxiliary equipment, etc. — all requiring resistance to high temperature and high pressure.
Delivery conditions:The goods can be delivered under various conditions, such as hot rolling, normalization, tempering, quenching, N+T, T+Q, etc. Z15-Z35 can also be provided.
Specifications & Standards:Refer to the table below
Consultation Hotline: 0086-371-55023661
| Category | Details |
|---|---|
| Executive Standards | International Standards: ASTM A633/A633M (High-Strength Low-Alloy Steel Plates for Structural Use), EN 10225 (Structural Steel for Marine Environments), API 2W (Steel for Offshore Welded Structures) Domestic Standards: GB/T 712-2011 (Structural Steel for Ships and Marine Engineering), GB/T 35138-2017 (High-Strength Steel Plates for Offshore Platforms) |
| Common Grades | ASTM A633 Gr.E, EN 10225 S355G8+M/S420G8+M, GB/T 712 DH36/EH36/FH36, API 2W Gr.50, A131 Gr.B |
| Specification Range | Thickness: 6 – 650 mm (conventional offshore platform plates); thick plates (≥ 60mm) support Z-direction performance (Z15/Z25/Z35) Width: 1200 – 4800 mm; Length: 3000 – 20000 mm (custom fixed-length plates for structural segments available) Delivery Form: Thermo-Mechanically Controlled Processing (TMCP), Normalized (N), Normalized + Tempered (N+T), Quenched & Tempered (Q+T, high-grade steel) |
| Chemical Composition (Typical Grades, %) | DH36 (GB/T 712): C ≤ 0.18, Si ≤ 0.50, Mn 0.90-1.60, P ≤ 0.035, S ≤ 0.035, Ni ≤ 0.40, Cr ≤ 0.20, Mo ≤ 0.08, Cu ≤ 0.30, Als ≥ 0.015 S355G8+M (EN 10225): C ≤ 0.18, Si ≤ 0.55, Mn ≤ 1.60, P ≤ 0.030, S ≤ 0.025, N ≤ 0.012, Cu ≤ 0.35- API 2W Gr.50: C ≤ 0.20, Mn 1.20-1.60, P ≤ 0.030, S ≤ 0.025, Cr ≤ 0.30, Mo ≤ 0.15, Ni ≤ 0.50 Core Requirements: Carbon Equivalent (CEV) ≤ 0.45% (ensures weldability), low sulfur and phosphorus (resists hydrogen-induced cracking) |
| Mechanical Properties (Room Temperature) | Yield Strength (σs): DH36 ≥ 355MPa, S420G8+M ≥ 420MPa, API 2W Gr.50 ≥ 345MPa (thickness ≤ 12mm) Tensile Strength (σb): DH36 490-630MPa, S420G8+M 540-720MPa, API 2W Gr.50 490-620MPa Elongation (A5): ≥ 21% (all grades) Low-Temperature Impact Energy (Akv): DH36 (-20℃) ≥ 34J, EH36 (-40℃) ≥ 34J, FH36 (-60℃) ≥ 34J (Charpy V-notch) Z-direction Performance: Z15 ≥ 15%, Z25 ≥ 25%, Z35 ≥ 35% (optional for thickness ≥ 40mm) |
| Heat Treatment State | Conventional: Thermo-Mechanically Controlled Processing (TMCP) for grain refinement and improved strength-toughness balance Thick Plates / High-Grade: Normalizing (880-920℃ air cooling) or Normalized + Tempered (620-680℃ air cooling) Quenched & Tempered Steel (e.g., FH36): Quenching (850-900℃ water cooling) + Tempering (580-640℃ air cooling) Core Requirements: Fatigue resistance, lamellar tearing resistance, adaptability to marine low-temperature, high-humidity, and salt-spray environments |
| Processing Adaptability | Welding: Preheating to 100-150℃ (thickness ＞ 25mm), use low-hydrogen electrodes (e.g., E7018-G), post-weld stress relief heat treatment (600-650℃) Cutting: Flame cutting (thick plates), plasma cutting (medium-thick plates), laser cutting (thin plates); preheating required before cutting to prevent cracking Forming: Cold bending radius ≥ 2× plate thickness (avoids lamellar tearing); supports large structural bending and rolling Surface Treatment: Factory-supplied with anti-rust primer (custom 3PE/anti-corrosion coatings available) |
| Environmental Resistance | Corrosion Resistance: Low sulfur-phosphorus design + Cu/Ni alloying for marine salt-spray corrosion resistance (corrosion rate ≤ 0.05mm/a after 1 year of outdoor exposure) HIC/SSC Resistance: API 2W grades pass NACE TM0284 (HIC) and NACE TM0177 (SSC) tests, suitable for sour oil and gas platforms Fatigue Resistance: Welded joint fatigue strength ≥ 120MPa (10⁷ cycles) |
| Application Fields | Offshore Platforms: Drilling platform jackets, deck structures, leg piles Floating Structures: FPSO (Floating Production Storage and Offloading) hulls, semi-submersible platform shells Marine Engineering Equipment: Subsea pipeline support structures, wind turbine foundations (monopiles), port crane bases Marine Vessel Structures: Ocean-going ship decks, hulls, bulkheads (EH36/FH36) |
| Inspection Requirements | Routine Testing: Chemical composition analysis, tensile test, low-temperature impact test, bending test, hardness test Non-Destructive Testing (NDT): Ultrasonic flaw detection (ASTM A578 Level B/GB/T 6402, 100% full coverage); magnetic particle/penetrant testing supplementary for thick plates Special Testing: Z-direction tensile test (thickness ≥ 40mm), HIC/SSC testing (sour service conditions), welded joint fatigue test Certificate Requirements: EN 10204 3.2 material certificate, classification society certification (ABS/DNV/BV/CCS) |
| Core Characteristics | Balance of Strength and Toughness: Excellent low-temperature toughness (maintains impact energy at -60℃) and resistance to wind-wave impact loads Weld Compatibility: Low carbon equivalent design enables on-site large-area welding without cracking risk Structural Safety: Z-direction performance prevents lamellar tearing, adapting to complex stress of marine structures Long-Term Stability: Salt-spray resistance and fatigue resistance, with a design service life of ≥ 25 years |
| Steel Grade | Standard | Thic(mm) | Width(mm) | Length(mm) |
| S355G2+N | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S355G5+M | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S355G3+N | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S355G6+M | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S355G7+N | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S355G8+N | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S355G9+N | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S355G10+N | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S355G7+M | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S355G8+M | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S355G9+M | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S355G10+M | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S420G1+Q | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S420G1+M, | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S420G2+Q | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S420G2+M | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S460G1+Q | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S460G1+M | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S460G2+Q | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S460G2+M | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S420G1+QT | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S420G2+QT | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S460G1+QT | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| S460G2+QT | EN10225 | 8-650 | 1200-3950 | 3000-20000 |
| Steel Grade | Standard | Thic(mm) | Width(mm) | Length(mm) | |
| A | LR, BV, ABS,DNV, GL and so on | 8-650 | 1200-3950 | 3000-20000 | |
| B | LR, BV, ABS,DNV, GL and so on | 8-650 | 1200-3950 | 3000-20000 | |
| D | LR, BV, ABS,DNV, GL and so on | 8-650 | 1200-3950 | 3000-20000 | |
| AH32 | LR, BV, ABS,DNV, GL and so on | 8-650 | 1200-3950 | 3000-20000 | |
| DH32 | LR, BV, ABS,DNV, GL and so on | 8-650 | 1200-3950 | 3000-20000 | |
| AH36 | LR, BV, ABS,DNV, GL and so on | 8-650 | 1200-3950 | 3000-20000 | |
| DH36 | LR, BV, ABS,DNV, GL and so on | 8-650 | 1200-3950 | 3000-20000 | |
| 2HGr50 | LR, BV, ABS,DNV, GL and so on | 8-650 | 1200-3950 | 3000-20000 | |
| E | LR, BV, ABS,DNV, GL and so on | 8-650 | 1200-3950 | 3000-20000 | |
| EH32 | LR, BV, ABS,DNV, GL and so on | 8-650 | 1200-3950 | 3000-20000 | |
| EH36 | LR, BV, ABS,DNV, GL and so on | 8-650 | 1200-3950 | 3000-20000 | |
| AH40 | LR, BV, ABS,DNV, GL and so on | 8-650 | 1200-3950 | 3000-20000 | |
| DH40 | LR, BV, ABS,DNV, GL and so on | 8-650 | 1200-3950 | 3000-20000 | |
| FH32 | LR, BV, ABS,DNV, GL and so on | 8-650 | 1200-3950 | 3000-20000 | |
| FH36 | LR, BV, ABS,DNV, GL and so on | 8-650 | 1200-3950 | 3000-20000 | |
| EH40 | LR, BV, ABS,DNV, GL and so on | 8-650 | 1200-3950 | 3000-20000 | |
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Copyright © 2019 HENAN STEEL GUANG INTERNATIONAL TRADE CO., LTD.
Global Hotline：0086-371-55023661
Copyright © 2019 HENAN STEEL GUANG INTERNATIONAL TRADE CO., LTD.