GL Grade A Shipbuilding Steel Coil
GL Grade A Shipbuilding Steel Coil - Material Data Sheet & Global Equivalents
Comprehensive material properties of GL Grade A shipbuilding steel coil: chemical composition, mechanical, thermal and electrical data, equivalent international grades, applications and processing guidelines.
Hot rolling, controlled rolling, normalizing (optional, depending on thickness)
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GL Grade A Shipbuilding Steel Coil Introduction
GL Grade A is a normal strength hull structural steel specified under the rules of Germanischer Lloyd (now part of DNV GL) and in accordance with IACS UR W11. It is intended for general shipbuilding applications and is typically supplied as coil, plate or sections in the hot-rolled condition. With a minimum yield strength of 235 MPa and good weldability, Grade A is widely used for primary and secondary hull members. The steel may be optionally normalized or delivered as "as-rolled". Its composition guarantees fine grain practice (e.g., aluminum content) to ensure satisfactory toughness, even without mandatory impact testing at ambient temperature. This grade is globally recognized and directly equivalent to ABS Grade A, LR Grade A, DNV Grade A and other classification societies, facilitating international procurement and design.
GL Grade A Shipbuilding Steel Coil Chemical Composition
The steel is produced with fine grain practice. Grain refining elements (e.g., Al) must be present in sufficient amounts. Residual elements are controlled to maintain weldability and toughness. All values correspond to GL Rules and IACS UR W11 for normal strength Grade A.
| Chemical Element | Standard Value (%) | Remarks |
|---|---|---|
| Carbon (C) | ≤ 0.21 | |
| Manganese (Mn) | ≥ 0.80* | * Mn ≥ 2.5 × C; typical range 0.80–1.20 |
| Silicon (Si) | ≤ 0.50 | |
| Phosphorus (P) | ≤ 0.035 | |
| Sulfur (S) | ≤ 0.035 | |
| Aluminum (Al) | ≥ 0.015 acid soluble (or ≥ 0.020 total) | Minimum required for fine grain practice |
| Chromium (Cr) | ≤ 0.20 (residual) | Higher contents by agreement |
| Nickel (Ni) | ≤ 0.40 (residual) | |
| Copper (Cu) | ≤ 0.35 (residual) | |
| Molybdenum (Mo) | ≤ 0.08 (residual) | |
| Nitrogen (N) | ≤ 0.012 | If not fixed by sufficient Al or other grain refiners |
| Total Aluminum (Al total) | ≥ 0.020 | If acid soluble Al not reported |
GL Grade A Shipbuilding Steel Coil Thermal, Electrical and Physical Properties
Typical data for carbon-manganese structural steel at room temperature, unless otherwise noted. Suitable for engineering calculations and simulation. Density, thermal expansion and conductivity are essential for design and welding preheat estimates.
| Property | Standard Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7850 | kg/m³ | 20 °C |
| Modulus of Elasticity (E) | 210 | GPa | 20 °C |
| Shear Modulus (G) | 81 | GPa | 20 °C, calculated |
| Poisson's Ratio (ν) | 0.3 | – | – |
| Thermal Expansion Coefficient (α) | 11.7 × 10⁻⁶ | 1/K | 20–100 °C |
| Thermal Conductivity (λ) | 51.9 | W/(m·K) | 20 °C |
| Specific Heat Capacity (cₚ) | 486 | J/(kg·K) | 20 °C |
| Electrical Resistivity (ρₑ) | 0.15 × 10⁻⁶ | Ω·m | 20 °C |
GL Grade A Shipbuilding Steel Coil Mechanical Properties
Properties derived from GL Rules for shipbuilding steel Grade A and IACS UR W11. Tensile test direction is longitudinal. Bend test requires 180° bending without cracking. Impact values are guaranteed for longitudinal specimens at 20°C (when impact test is specified).
| Property | Standard Requirement | Unit | Test Condition / Thickness (mm) |
|---|---|---|---|
| Yield Strength (ReH) | ≥ 235 | MPa | t ≤ 50 |
| Yield Strength (ReH) | ≥ 225 | MPa | 50 < t ≤ 100 |
| Tensile Strength (Rm) | 400–520 | MPa | t ≤ 100 |
| Elongation (A5) | ≥ 22 | % | t ≤ 50, gauge length 5.65√S₀ |
| Elongation (A5) | ≥ 22 | % | 50 < t ≤ 100 |
| Impact Energy (KV, longitudinal) | ≥ 27 (average) | J | +20 °C, t ≤ 50 (if required) |
| Impact Energy (KV, longitudinal) | ≥ 27 (average) | J | +20 °C, 50 < t ≤ 100 |
| Bend Test (180°) | d = 2a (no cracks) | – | t ≤ 50, where a = specimen thickness |
| Bend Test (180°) | d = 3a (no cracks) | – | 50 < t ≤ 100 |
GL Grade A Shipbuilding Steel Coil Completely Equivalent Grades and Substitutable Standards
| Country/Organization | Standard/Guideline | Grade | Remarks |
|---|---|---|---|
| International Association of Classification Societies | IACS UR W11 | Grade A | Normal strength hull structural steel |
| Germany (GL / DNV GL) | GL Rules for Materials | GL Grade A | Original standard; now incorporated in DNV GL rules |
| Norway (DNV) | DNV Rules for Ships | DNV Grade A | Equivalent to GL Grade A |
| United States (ABS) | ABS Rules for Materials | ABS Grade A | Full interchangeability |
| United Kingdom (LR) | LR Rules for Materials | LR Grade A | |
| France (BV) | BV Rules for Materials | BV Grade A | |
| China (CCS) | CCS Rules for Materials | CCS A | |
| Japan (NK) | NK Rules for Materials | NK Grade A | |
| Korea (KR) | KR Rules for Materials | KR Grade A | |
| Italy (RINA) | RINA Rules for Materials | RINA Grade A | |
| Russia (RS) | RS Rules for Materials | RS Grade A |
GL Grade A Shipbuilding Steel Coil Application Introduction
GL Grade A steel is engineered for primary and secondary ship structures. It can be formed, welded and machined using conventional methods. Coil form allows efficient production of shear panels, stiffeners and deck plates through modern cutting and straightening lines.
Product Applications: Hull shell plates, Deck plates, Bulkhead panels, Longitudinal and transverse stiffeners, Floor and web frames
Processed into products: Main deck plating, Side shell plates, Bilge strakes, Keel plates, Stringer plates, Transverse webs, Floor plates, Superstructure panels
Application industries: Shipbuilding, Marine engineering and repair, Offshore structure fabrication, Barge and pontoon construction, Defense (naval auxiliary vessels)
GL Grade A Shipbuilding Steel Coil Similar/Alternative Materials
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10025-2 | S235JR | Structural steel with similar strength; chemistry differs slightly; not classification society approved |
| USA | ASTM A36 / A36M | A36 | Carbon structural steel; comparable minimum yield strength; additional verification needed for marine use |
| International | ISO 630-2 | S235B | Similar mechanical properties under ISO standard for structural steels |
Notes:
Delivery condition: As-rolled or normalized, depending on thickness and end use; all shipments must be accompanied by a classification society certificate (e.g., DNV GL certificate). Weldability: Excellent with standard procedures; preheat usually not required for moderate thicknesses; adoption of fine grain practice guarantees adequate notch toughness even in the as-rolled condition. Further processing: Suitable for cutting, cold forming, bending and welding; galvanizing possible if surface and composition allow.
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