KR AH36 Shipbuilding Steel Coil
KR AH36 Shipbuilding Steel Coil - Korean Register High-Strength Hull Structural Steel
Detailed material data for KR AH36 shipbuilding steel coil according to Korean Register Rules for Steel Ships. Includes chemical composition, mechanical properties, thermal and electrical physical properties, equivalent grades, and application guidelines.
Hot rolling, controlled rolling, normalizing, thermomechanical rolling (TMCP)
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KR AH36 Shipbuilding Steel Coil Introduction
KR AH36 is a high-strength hull structural steel grade specified by the Korean Register (KR) for use in shipbuilding and offshore structures. It belongs to the AH36 category, where 'A' indicates impact testing at 0°C and 'H36' designates a minimum yield strength of 355 MPa. This steel is primarily supplied in coil form and is designed for welded structures in marine environments, offering excellent toughness, weldability, and corrosion resistance. Typical applications include hull plates, decks, and other structural components of ships and offshore platforms. It is produced via controlled rolling or normalizing processes to achieve the required mechanical properties. KR AH36 is fully compliant with the KR Rules for the Classification of Steel Ships and is widely accepted in global shipbuilding projects.
KR AH36 Shipbuilding Steel Coil Chemical Composition
The chemical composition of KR AH36 shall comply with the ladle analysis limits specified in the KR Rules for high-strength hull structural steels. The values below represent the maximum allowed contents unless a range is given. All values are in weight percent.
| Element | Standard Value | Remarks |
|---|---|---|
| Carbon (C) | ≤ 0.18 | Max |
| Manganese (Mn) | 0.90 - 1.60 | Range |
| Silicon (Si) | 0.10 - 0.50 | Range |
| Phosphorus (P) | ≤ 0.035 | Max |
| Sulfur (S) | ≤ 0.035 | Max |
| Copper (Cu) | ≤ 0.35 | Max |
| Chromium (Cr) | ≤ 0.20 | Max |
| Nickel (Ni) | ≤ 0.40 | Max |
| Molybdenum (Mo) | ≤ 0.08 | Max |
| Aluminum (Al) total | ≥ 0.015 | Min, if used for grain refining |
| Niobium (Nb) | 0.02 - 0.05 | If added |
| Vanadium (V) | 0.05 - 0.10 | If added |
| Titanium (Ti) | ≤ 0.02 | If added |
| Nitrogen (N) | ≤ 0.009 | If not combined with strong nitride formers |
KR AH36 Shipbuilding Steel Coil Thermal and Electrical Physical Properties
Physical properties are typical for AH36 grade steel and may vary slightly depending on exact composition and heat treatment. These values are provided for design reference and are not mandatory certification parameters.
| Property | Standard Required Value | Unit | Test Condition / Remarks |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | At room temperature |
| Elastic Modulus (E) | 205 - 210, approx. 207 | GPa | At 20°C |
| Shear Modulus (G) | approx. 80 | GPa | Calculated from E and Poisson ratio |
| Poisson's Ratio (ν) | 0.3 | - | Within elastic range |
| Thermal Expansion Coefficient (α) | 11.9 (avg. 20-100°C); 12.5 (20-200°C); 13.6 (20-400°C) | 10⁻⁶/K | Linear expansion |
| Thermal Conductivity (λ) | approx. 52 | W/(m·K) | At 20°C |
| Specific Heat Capacity | approx. 460 | J/(kg·K) | At 20°C |
| Electrical Resistivity (ρe) | approx. 0.22 | μΩ·m | At 20°C |
KR AH36 Shipbuilding Steel Coil Mechanical Properties
Mechanical properties are verified on test pieces taken from the finished product in delivery condition. Tensile testing is performed in accordance with KR Rules, and impact tests are carried out on Charpy V-notch specimens at 0°C for grade A. Properties vary with product thickness.
| Property | Standard Required Value | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) | ≥ 355 | MPa | Thickness ≤ 100 mm |
| Tensile Strength (Rm) | 490 - 620 | MPa | Thickness ≤ 100 mm |
| Elongation (A) | ≥ 21 | % | Gauge length 5.65√So, thickness ≤ 50 mm |
| Elongation (A) | ≥ 19 | % | Thickness > 50 mm |
| Charpy Impact Energy (KV) | ≥ 24 (longitudinal) / ≥ 17 (transverse) | J | At 0°C, V-notch |
| Bend Test (180°) | No cracks | - | Normal direction; mandrel diameter 3a (a = thickness) for AST 355 |
KR AH36 Shipbuilding Steel Coil Completely Equivalent Material Standards & Replaceable Grade Recommendations
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| International | IACS W13 | AH36 | Adopted by all IACS members |
| USA | ASTM A131 / A131M | AH36 | American Bureau of Shipping |
| USA | ABS Rules | AH36 | American Bureau of Shipping |
| Norway/Germany | DNV GL Rules | AH36 | Det Norske Veritas Germanischer Lloyd |
| UK | LR Rules | AH36 | Lloyd's Register |
| France | BV Rules | AH36 | Bureau Veritas |
| China | GB/T 712 | AH36 | China Classification Society (CCS) |
| China | CCS Rules | AH36 | China Classification Society |
| Japan | NK Rules | AH36 | ClassNK (Nippon Kaiji Kyokai) |
| Italy | RINA Rules | AH36 | Registro Italiano Navale |
| South Korea | KR Rules | AH36 | Korean Register - Original Standard |
KR AH36 Shipbuilding Steel Coil Application Introduction
KR AH36 is specifically designed for welded ship structures and marine applications where high strength and good low-temperature toughness are required. It is most commonly used in the form of plates and coils for the construction of hulls, decks, bulkheads, and other structural members. The steel can be processed by cutting, cold forming, welding, and machining. Pre-fabrication treatments like shot blasting and shop priming are typical. The guaranteed impact properties at 0°C make it suitable for moderate climates; for Arctic service, DH36 or EH36 grades are preferred.
Product Applications: Merchant vessels (bulk carriers, tankers, container ships), Naval ships, Floating production storage and offloading (FPSO) units, Offshore drilling platforms and jack-up rig legs, Hulls for tugs, barges, and workboats
Processed into products: Hull plates (side shell, bottom shell, weather deck), Transverse and longitudinal stiffeners, Bulkheads, Deck panels, Hatch coamings, Offshore module support structure
Application industries: Shipbuilding, Offshore oil & gas, Marine engineering, Port and harbor infrastructure, Renewable energy (offshore wind platforms)
KR AH36 Shipbuilding Steel Coil Similar / Alternative Material Recommendations
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| EU | EN 10025-3 | S355N / S355NL | Structural steel with comparable yield; not certified for ship class but often used |
| USA | ASTM A572 | Grade 50 (345 MPa) | Lower yield strength but similar tensile properties; not specifically for shipbuilding |
| IACS | Class Rules | AH32 | Lower strength shipbuilding grade (min Re 315 MPa); may substitute if design allows |
| IACS | Class Rules | DH36 | -20°C impact toughness, otherwise same strength; can be used where lower temperature toughness is needed |
| Japan | JIS G3106 | SM490B | Welded structural steel with min yield 355 MPa; not class-approved for primary ship structures |
Notes:
For thicknesses greater than 100 mm, mechanical properties shall be agreed between the purchaser and the manufacturer. KR AH36 can be supplied with additional options such as through-thickness property testing (Z-quality), enhanced corrosion protection, or certificates for specific fabrication. Note that in common commercial language, 'A36' often refers to ASTM A36 structural steel (yield 250 MPa), but in the context of KR shipbuilding steel, it correctly refers to the high-strength grade AH36 (yield 355 MPa). Ensure clear specification when ordering.
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