NK A36 Shipbuilding Steel Coil
NK A36 Shipbuilding Steel Coil: High Strength Hull Structural Steel
Comprehensive material data for NK A36 shipbuilding steel coil, including chemical composition, mechanical and thermal properties, equivalent grades, and applications for ship hull construction.
Hot rolling, controlled rolling, normalizing, TMCP, cutting, forming, welding
- Phone : +8618037372205
- Email : [email protected]
- WhatsApp: Contact via Whtsapp
- WeChat: +8618037372205
NK A36 Shipbuilding Steel Coil Introduction
NK A36 is a high strength hull structural steel grade certified by Nippon Kaiji Kyokai (ClassNK) for shipbuilding applications. It is specified under the NK Rules for the Classification of Ships, Part K Materials. This steel offers a minimum yield strength of 355 MPa, excellent weldability, and good toughness at specified temperatures, making it suitable for critical ship structures. The grade corresponds to the higher strength series with a yield strength of 36 ksi (approx. 355 MPa) and is typically supplied in normalized or thermo-mechanically controlled processed (TMCP) condition as hot-rolled coils.
NK A36 Shipbuilding Steel Coil Chemical Composition
The chemical composition of NK KA36 (A36) steel is tightly controlled to ensure excellent weldability and mechanical properties. The table below shows the typical ladle analysis requirements as per NK Rules. Microalloying elements like Nb, V, Ti may be added to achieve grain refinement and precipitation strengthening. Carbon equivalent (CE) is usually limited for good weldability.
| Element | Specified Value (max % unless range) | Remarks |
|---|---|---|
| Carbon (C) | ≤0.18% | Higher carbon may reduce toughness |
| Manganese (Mn) | 0.90–1.60% | Depending on thickness and CE |
| Silicon (Si) | ≤0.50% | Deoxidation element |
| Phosphorus (P) | ≤0.035% | Phosphorus embrittlement control |
| Sulfur (S) | ≤0.035% | For improved ductility |
| Aluminum (Al) | ≥0.015% (acid soluble) | Fine grain practice |
| Niobium (Nb) | ≤0.05% | Optional grain refiner |
| Vanadium (V) | ≤0.10% | Optional precipitation hardening |
| Titanium (Ti) | ≤0.02% | Optional for grain refinement |
| Copper (Cu) | ≤0.35% | If applicable for corrosion resistance |
| Chromium (Cr) | ≤0.20% | Residual element |
| Nickel (Ni) | ≤0.40% | Residual element |
| Molybdenum (Mo) | ≤0.08% | Residual element |
| Carbon Equivalent (CE) | ≤0.38% (typical) | CE = C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15 |
NK A36 Shipbuilding Steel Coil Thermal and Electrical Physical Properties
The following physical properties are typical for carbon-manganese structural steel similar to NK KA36. These values are not mandated by the classification society but are useful for design calculations. Data are for ambient conditions unless otherwise noted.
| Property | Typical Value | Unit | Test Condition / Remarks |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | At 20°C |
| Elastic Modulus (E) | 210 | GPa | Tensile modulus, ambient |
| Shear Modulus (G) | 80 | GPa | Calculated from E and ν |
| Poisson's Ratio (ν) | 0.3 | — | Dimensionless |
| Thermal Expansion Coefficient (α) | 12.0 | 10⁻⁶/K | 20–100°C |
| Thermal Conductivity (λ) | 50 | W/(m·K) | At 20°C |
| Specific Heat Capacity (cp) | 460 | J/(kg·K) | At 20°C |
| Electrical Resistivity (ρ_e) | 0.20 | µΩ·m | At 20°C |
NK A36 Shipbuilding Steel Coil Mechanical Properties
Mechanical properties of NK KA36 are determined on test pieces taken in the longitudinal direction. Tensile test and Charpy V-notch impact test are mandatory. The values below represent the minimum requirements for various thicknesses. Impact test temperature is 0°C for grade A36.
| Property | Specified Value | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) | ≥355 | MPa | Thickness ≤ 50 mm |
| Yield Strength (ReH) | ≥345 | MPa | Thickness > 50 mm ≤ 70 mm |
| Yield Strength (ReH) | ≥325 | MPa | Thickness > 70 mm ≤ 100 mm |
| Tensile Strength (Rm) | 490–620 | MPa | All thicknesses |
| Elongation (A) | ≥21 | % | Gauge length 5.65√So, t ≤ 50 mm |
| Elongation (A) | ≥20 | % | t > 50 mm ≤ 70 mm |
| Elongation (A) | ≥19 | % | t > 70 mm ≤ 100 mm |
| Charpy Impact Energy (KV) | ≥34 (longitudinal) | J | At 0°C, t ≤ 50 mm |
| Charpy Impact Energy (KV) | ≥24 (longitudinal) | J | At 0°C, 50 < t ≤ 70 mm |
| Charpy Impact Energy (KV) | ≥27 (longitudinal) | J | At 0°C, 70 < t ≤ 100 mm (subject to agreement) |
| Bend Test | D=2a (180°) | — | Thickness ≤ 25 mm; D=3a for thicker plates |
NK A36 Shipbuilding Steel Coil Fully Equivalent Material Standards and Substitute Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| USA | ABS | AH36 | High strength hull structural steel, same yield strength level |
| France | BV | AH36 | Bureau Veritas equivalent |
| Norway/Germany | DNV GL | AH36 | Det Norske Veritas Germanischer Lloyd |
| UK | LR | AH36 | Lloyd's Register equivalent |
| Italy | RINA | AH36 | Registro Italiano Navale |
| China | CCS | AH36 | China Classification Society |
| Korea | KR | AH36 | Korean Register |
| Russia | RS | A36 | Russian Maritime Register of Shipping |
| Japan | JIS G3106 | SM490A/C (close) | Not identical, similar strength, but supplementary requirements needed |
NK A36 Shipbuilding Steel Coil Application Introduction
NK KA36 steel is predominantly used in the construction of seagoing ships, offshore platforms, and marine structures. Its high strength and good weldability allow weight reduction while maintaining structural integrity. The steel is suitable for cold forming and can be cut by flame, plasma, or laser methods. It is often delivered as coil for subsequent cutting and fabrication into various structural members.
Product Applications: Ship hull plates (deck, side, bottom), Longitudinal and transverse bulkheads, Stiffeners, girders, and stringers, Deckhouses and superstructures, Offshore structural modules, Barge and pontoon structures
Processed into products: Keel plates, Bilge strakes, Sheer strakes, Web frames and floor plates, Hatch coaming and coaming stiffeners, Deck beams and columns, Crane pedestals and foundations, Rudder horn and stern frame plates
Application industries: Shipbuilding and repair, Offshore oil & gas platforms, Marine engineering, Port and harbor construction, Bridge construction (where approved), Pressure vessels and boilers (subject to additional requirements)
NK A36 Shipbuilding Steel Coil Similar Substitute Materials with Close Properties
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| USA | ASTM A572 | Grade 50 | Similar yield strength, general structural quality, not classified for marine use without certification |
| Europe | EN 10025-4 | S355ML | Thermo-mechanical rolled, minimum yield 355 MPa, requires additional testing for ship approval |
| Europe | EN 10025-2 | S355J2 | Structural steel, similar strength, but less stringent toughness |
| China | GB/T 712 | AH36 | Chinese shipbuilding steel, equivalent to CCS AH36 |
Notes:
All data provided are based on publicly available NK Rules and typical industry practices. Actual supplied material may have tighter controls as agreed between buyer and manufacturer. Always refer to the latest edition of the classification society rules and product certificates for specific requirements. The thermal and electrical properties are typical and not part of the official material certification.
- Share
