RINA DH620 Shipbuilding Steel Coil
RINA DH620 Shipbuilding Steel Coil - High Strength Quenched and Tempered Marine Grade
Comprehensive data sheet for RINA DH620 shipbuilding steel coil: chemical composition, mechanical properties, thermal and electrical physical properties, equivalent grades, and application guide.
Hot rolling, cold forming, welding, cutting, bending
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RINA DH620 Shipbuilding Steel Coil Introduction
RINA DH620 is a high-strength quenched and tempered steel coil for shipbuilding and offshore structures, certified by the Italian classification society RINA. It meets the requirements of the International Association of Classification Societies (IACS) UR W31 for extra high strength steels with minimum yield strength of 620 MPa and notch toughness at -20°C (DH class). The steel offers excellent weldability and toughness for heavy marine applications.
Key features:
- Minimum yield strength 620 MPa
- Charpy V-notch impact energy ≥27 J at -20°C (transverse)
- Good combination of strength, toughness and weldability
- Supplied in coil form for efficient fabrication
RINA DH620 Shipbuilding Steel Coil Chemical Composition
Chemical limits as per IACS UR W31 for grade 620 steel (applicable to RINA DH620). Values are maximum unless a range is indicated. Fine grain practice with sufficient aluminium or other grain refining elements is mandatory.
- Carbon Equivalent (CEV) typically limited to avoid weld cracking.
- Tramp elements controlled for toughness.
| Element | Max/Min (%) | Remarks |
|---|---|---|
| C (Carbon) | ≤0.20 | thickness ≤50 mm |
| Si (Silicon) | ≤0.55 | |
| Mn (Manganese) | 1.00–1.70 | |
| P (Phosphorus) | ≤0.025 | |
| S (Sulfur) | ≤0.025 | |
| Cu (Copper) | ≤0.50 | |
| Cr (Chromium) | ≤0.80 | |
| Ni (Nickel) | ≤2.00 | |
| Mo (Molybdenum) | ≤0.70 | |
| Nb (Niobium) | ≤0.06 | |
| V (Vanadium) | ≤0.10 | |
| Ti (Titanium) | ≤0.05 | |
| Al (Aluminium, total) | ≥0.015 | Minimum for grain refinement |
| N (Nitrogen) | ≤0.012 |
RINA DH620 Shipbuilding Steel Coil Thermal and Electrical Physical Properties
Typical physical properties for low‑alloy quenched and tempered steel. These values are not part of the material certification but are useful for design calculations. Slight variations may occur depending on exact chemistry and heat treatment.
| Property | Typical Value | Unit | Reference Condition |
|---|---|---|---|
| Density (ρ) | 7850 | kg/m³ | At 20°C |
| Elastic Modulus (E) | 205–210 | GPa | Room temperature |
| Shear Modulus (G) | ~80 | GPa | Calculated |
| Poisson's Ratio (ν) | 0.30 | Elastic range | |
| Thermal Expansion Coefficient (α) | 12 | 10⁻⁶/K | 20–100°C |
| Thermal Conductivity (λ) | 45 | W/(m·K) | At 20°C |
| Specific Heat Capacity | 460 | J/(kg·K) | At 20°C |
| Electrical Resistivity (ρ_e) | 0.20–0.25 | Ω·mm²/m (×10⁻⁶ Ω·m) | At 20°C |
RINA DH620 Shipbuilding Steel Coil Mechanical Properties
Mechanical properties for RINA DH620 steel coil in quenched and tempered condition, tested at room temperature. Values comply with IACS UR W31. Impact test specimens are taken transverse to the rolling direction.
- Yield and tensile values valid for thickness up to 50 mm (for coil typical thin gauge).
- Elongation measured on a gauge length of 5.65√S₀.
| Property | Specified Value | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) | ≥620 | MPa | Room temperature, t ≤50 mm |
| Tensile Strength (Rm) | 720–890 | MPa | t ≤50 mm |
| Elongation (A) | ≥14 | % | L₀=5.65√S₀, t ≤100 mm |
| Charpy Impact Energy (KV) | ≥27 (average) | J | -20°C, transverse, min 3 specimens |
| Bend Test | No cracks | 180° bend, diameter = 3t (t ≤30 mm) |
RINA DH620 Shipbuilding Steel Coil Fully Equivalent Material Standards and Substitute Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| International | IACS UR W31 | DH620 | Unified requirement for extra high strength Q&T steel |
| USA | ABS Rules | ABS DH620 | American Bureau of Shipping |
| Norway/Germany | DNV Rules | DNV DH620 | DNV GL (now DNV) |
| France | BV Rules | BV DH620 | Bureau Veritas |
| UK | LR Rules | LR DH620 | Lloyd's Register |
| China | CCS Rules | CCS DH620 | China Classification Society |
| Japan | NK Rules | NK DH620 | ClassNK |
| Korea | KR Rules | KR DH620 | Korean Register |
RINA DH620 Shipbuilding Steel Coil Application Introduction
RINA DH620 steel coil is designed for welded structures in shipbuilding and offshore engineering where high strength and toughness at sub‑zero temperatures are essential. Its coil form allows efficient processing into structural members by decoiling, cutting, forming and welding.
Key application notes:
- Excellent weldability with low‑hydrogen processes; preheating may be required for thick sections.
- Adequate forming properties for cold bending, rolling and pressing.
- Charpy toughness at -20°C ensures safe operation in cold sea environments.
- Often used in combination with higher grade steels (e.g., DH690) in weight‑sensitive designs.
Product Applications: Ship hull plates and sections, Decks and bulkheads, Stiffeners and frames, Offshore module skids and structures, Crane booms, legs and pedestals, Jack‑up rig legs and spudcans, Wind turbine transition pieces
Processed into products: Rolled stiffeners and flat bars, Cut and formed brackets, Welded box girders, Crane slewing rings, Base frames for heavy equipment, Deck machinery interfaces
Application industries: Shipbuilding and ship repair, Offshore oil & gas (platforms, FPSOs, subsea templates), Marine renewable energy (wind turbine foundations), Heavy lifting and crane manufacturing, Pressure vessel (non‑code applications)
RINA DH620 Shipbuilding Steel Coil Similar/Comparable Material Recommendations
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| International | IACS UR W31 | EH620 | Same strength, lower impact temperature (-40°C) |
| International | IACS UR W31 | DH550 | Lower strength class, suitable if 620 MPa yield not required |
| International | IACS UR W31 | DH690 | Higher strength class, yield 690 MPa |
| Europe | EN 10025-6 | S620Q | Structural Q&T steel, not specifically for shipbuilding; verify notch toughness |
| USA | ASTM A514 | Grade B/E | High yield Q&T constructional alloy steel; check toughness requirements |
Notes:
Additional remarks:
- RINA certification should be obtained for each batch. The material is stamped with RINA mark, grade, heat number and surveyor's identification.
- Supplementary testing such as CTOD or Z‑direction tensile may be agreed between manufacturer and purchaser.
- For coiled products, not all mechanical properties may be guaranteed after subsequent cold deformation; appropriate stress relieving may be needed after forming.
- The information above is based on publicly available IACS UR W31 and common classification society practice; for actual project requirements, refer to the latest RINA Rules or specific mill certificate.
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