LR Grade EH69 Shipbuilding Steel Plate
LR Grade EH69 Shipbuilding Steel Plate: 690 MPa Yield Strength & Cryogenic Toughness for Marine Structures
Comprehensive properties of LR Grade EH69 quenched and tempered shipbuilding steel plate per IACS UR W11. Includes chemical composition, mechanical properties at -40°C, physical constants, equivalent grades, and application guide for offshore and ship structures.
Hot rolling followed by quenching and tempering; cutting, forming, welding, machining after fabrication
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LR Grade EH69 Shipbuilding Steel Plate Introduction
LR Grade EH69 is a high-strength, quenched and tempered shipbuilding steel plate with a minimum yield strength of 690 MPa. It belongs to the extra-high strength category as defined by Lloyd's Register (LR) and IACS UR W11. The grade delivers excellent toughness at -40°C, suitable for critical structural members in ships and offshore installations where heavy loading and low-temperature service are encountered.
- Designed for welded construction under strict class society rules.
- Offers a good balance of strength, ductility, and weldability through controlled microalloying and QT treatment.
- Used primarily in hull framing, decks, and legs of jack-up rigs.
LR Grade EH69 Shipbuilding Steel Plate Chemical Composition , mass %
The chemical composition limits for LR Grade EH69 are taken from IACS UR W11 for H690 (EH690) grade. Values are maximum unless a range is indicated. Elements like Al, Nb, V, Ti, or B may be added as grain refiners. The steel is fully killed and fine grain treated. Typical actual heat analysis is often below 0.18% C to maintain weldability.
| Chemical Element | Specified Value (max) | Remarks |
|---|---|---|
| C | 0.20 | Max |
| Si | 0.55 | Max |
| Mn | 1.70 | Max |
| P | 0.025 | Max |
| S | 0.025 | Max |
| Cu | 0.50 | Max |
| Cr | 1.50 | Max |
| Ni | 2.00 | Max |
| Mo | 0.70 | Max |
| V (if added) | 0.10 | Max |
| Nb | 0.05 | Max |
| Ti (if added) | 0.05 | Max |
| Al (total, if added) | 0.020 min | Minimum requirement |
| N | 0.020 | Max |
| B (if added) | 0.005 | Max |
LR Grade EH69 Shipbuilding Steel Plate Physical Properties
Physical properties are provided for quenched and tempered low-alloy structural steel with density ~7.85 g/cm³. These values are representative for similar Cr-Ni-Mo steels and do not form part of the LR certification requirements. Thermal conductivity decreases with increasing temperature. Data compiled from references for S690 grade type steels.
| Property | Typical Value | Unit | Test Condition / Remarks |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | At 20°C |
| Modulus of Elasticity (E) | 205 | GPa | At 20°C |
| Shear Modulus (G) | 80 | GPa | Calculated from E and ν |
| Poisson's Ratio (ν) | 0.3 | — | Typical for steel |
| Thermal Expansion Coeff. (α) | 11.5 | 10⁻⁶/K | 20–100°C |
| Thermal Expansion Coeff. (α) | 12.5 | 10⁻⁶/K | 20–200°C |
| Thermal Expansion Coeff. (α) | 13.5 | 10⁻⁶/K | 20–400°C |
| Thermal Conductivity (λ) | 36 | W/(m·K) | At 20°C |
| Thermal Conductivity (λ) | 34 | W/(m·K) | At 200°C |
| Specific Heat Capacity | 480 | J/(kg·K) | Approximate at 20°C |
| Electrical Resistivity (ρₑ) | 0.25 | μΩ·m | At room temperature |
LR Grade EH69 Shipbuilding Steel Plate Mechanical Properties
Mechanical tests are performed on transverse test pieces from plates in the Quenched & Tempered condition. Values refer to IACS UR W11 for grade EH690 (EH69). Minimum impact energy is verified at -40°C. For thicknesses beyond 100 mm, properties may be subject to agreement. Bending is 180° around a former with diameter 3 times specimen thickness (3a).
| Property | Specified Value | Unit | Test Condition / Remarks |
|---|---|---|---|
| Yield Strength (ReH) | 690 (min) | MPa | t ≤ 100 mm; transverse |
| Tensile Strength (Rm) | 770–940 | MPa | t ≤ 100 mm; transverse |
| Elongation (A) | 14 (min) | % | Gauge L0 = 5.65√So; t ≤ 100 mm; transverse |
| Elongation (A) | 12 (min) | % | t > 100 mm; agreed case |
| Impact Energy (KV2) | 69 (min) | J | Longitudinal; -40°C; average of 3 specimens |
| Impact Energy (KV2) | 46 (min) | J | Transverse; -40°C; average of 3 specimens |
| Bend Test | No cracks | — | D = 3a; 180° |
LR Grade EH69 Shipbuilding Steel Plate Fully Equivalent Material Standards and Replaceable Grades
| Country / Region | Standard / Specification | Grade Designation | Remarks |
|---|---|---|---|
| International (IACS) | IACS UR W11 | EH690 | Identical technical delivery conditions |
| USA | ABS Rules | EH69 | American Bureau of Shipping equivalent |
| Norway/Germany | DNV Rules | E690 | Det Norske Veritas equivalent |
| France | BV Rules | EH69 | Bureau Veritas equivalent |
| China | CCS Rules | EH690 | China Classification Society equivalent |
| Japan | NK Rules | EH69 | Nippon Kaiji Kyokai equivalent |
| Korea | KR Rules | EH69 | Korean Register equivalent |
| Italy | RINA Rules | EH69 | Registro Italiano Navale equivalent |
LR Grade EH69 Shipbuilding Steel Plate Application Introduction
LR Grade EH69 plates are engineered for heavy-duty welded fabrications in the marine and offshore industry. The combination of 690 MPa yield strength and reliable toughness at -40°C permits lighter designs, higher payloads, and safe operation in cold environments.
- Preheating (50–100°C) and proper hydrogen control are required during welding due to the high strength level.
- Post-weld heat treatment is generally not mandatory but may be applied for thicknesses above 50 mm to relieve residual stress.
- Workability and formability are good in the QT condition; hot forming may require re-tempering.
Product Applications: Main deck plates and hatch coamings of ultra-large container carriers, Leg structures of self-elevating (jack-up) mobile offshore units, Tubular nodes and collars for offshore jack-ups, Reinforced hull inserts in ice-going vessels, Crane pedestal stools and boom chords
Processed into products: Hull framing and girder webs (high stress regions), Cross braces for offshore platform legs, Heavy padeyes and lifting lugs, Shaft stools and engine foundation seating, Aft and forward structural modules of drill ships
Application industries: Shipbuilding (large container vessels, bulk carriers, ice-class ships), Offshore oil & gas (jack-up rigs, semi-submersibles, platform legs), Renewable energy (offshore wind turbine foundations, transition pieces), Heavy lifting equipment (crane booms, heavy lift vessels), Defence (naval auxiliary hulls, submarine components)
LR Grade EH69 Shipbuilding Steel Plate Similar / Comparable Material Recommendations
| Country / Region | Standard / Specification | Grade Designation | Remarks |
|---|---|---|---|
| Europe | EN 10025-6 | S690Q / S690QL | Structural QT steel; similar strength but not certified for ship classification; may require additional testing for marine use. |
| USA | ASTM A514 / A517 | Grade Q / S / E | High strength QT structural plate; 690 MPa yield; Charpy values and temperatures must be verified to match EH69 requirements. |
| Japan | JIS G 3128 | SHY 685 / SHY 70 | High yield strength steel for welded structures; compare toughness and chemistry. |
| China | GB/T 16270 | Q690D / Q690E | High strength structural steel; may have different impact temperature (-20°C or -40°C). |
Notes:
Welding: Use low hydrogen processes (SMAW with basic electrodes, SAW, GMAW) and consumables matching the minimum 690 MPa yield. Heat input and interpass temperature must be controlled to avoid heat-affected zone softening. 2024 IACS UR W11 edition applies; for earlier revisions verify Charpy requirements. If plates are to be hot formed above the tempering temperature, subsequent re-tempering is required. Certification: Each plate must be marked with LR stamp, heat number, and grade, and delivered with 3.1 certificate per EN 10204.
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