What is Marine steel plate?
Marine steel plate is a type of steel plate specifically used for shipbuilding and Marine engineering structures. Compared with ordinary structural steel, it has very high requirements for strength, ductility, corrosion resistance and weldability.
Common perforated steel plates can be classified by grade into: ordinary strength ship plates (A, B, C, D) and high-strength ship plates (AH32, DH36, EH36, FH40, etc.).
The standards and certification system of Marine steel plate
Marine steel plates must comply with international standards and classification society certification requirements to ensure safety and reliability. The following are common standards and certification systems:
ASTM A131: American standard. This grade is defined as ordinary strength, with a specified minimum yield strength of 34Ksi, and is applicable to plates used in ships and Marine structures.
EN10025: European Standard for structural Steel and Marine engineering steel.
ABS/LR/BV/DNV/CCS/GL: Certified by classification societies of various countries, representing the quality and seaworthiness of steel plates.
For example: ABS AH36 indicates high-strength ship plates certified by the American Bureau of Shipping (ABS); LR DH36 indicates Lloyd's Register certified high-strength ship plates of the United Kingdom.
Chemical composition and purity control
Carbon (C) : ≤0.25% (for general strength steel) → ≤0.16% (for high-strength steel), reducing the risk of welding cracking.
Manganese (Mn) : 1.00% - 1.60% (such as DH36), which works in synergy with carbon to enhance strength and refine grain size.
Sulfur and phosphorus (S/P) : General standard: S≤0.035%, P≤0.035%
Upgrade standard (polar/deep-sea steel) : S≤0.010%, P≤0.020%, reducing hydrogen-induced cracking (HIC).
Microalloying elements: niobium (Nb), vanadium (V) : Refine grains and enhance strength (for example, 0.02-0.05%Nb is added to EH40).
Nickel (Ni) : 2.0% - 5.0% (for low-temperature steel), ensuring toughness at -196℃ (LNG ship liquid tanks).
These elements ensure that the steel plate has excellent weldability and resistance to seawater corrosion.
Common specifications and technical parameters of Marine steel plate
Marine steel plates of different grades have slight differences in mechanical properties and application fields. The following are typical specifications of common high-strength Marine plates:
Grade | Yield strength(MPa) | Tensile strength (MPa) | Thickness (mm) |
| AH36 | ≥355 | 490–620 | 6–200 |
| DH36 | ≥355 | 490–620 | 6–200 |
| EH36 | ≥355 | 490–620 | 6–200 |
| FH40 | ≥390 | 510–650 | 6–150 |
Core application fields
Shipbuilding field
Bulk carriers/oil tankers: AH36 hull outer plates, B-class bulkhead plates
Large container ships: EH40 deck, FH40 side strong frame
LNG carrier: 9%Ni steel liquid cargo hold (in service at -196℃).
Marine engineering
Jacket platform: S420QLO pile legs (yield strength ≥460 MPa)
Floating Production Storage and Offloading vessel (FPSO) : FH40 fatigue deck.
How to choose the right Marine Steel Plate
When purchasing Marine steel plates, the following factors should be comprehensively considered:
Operating environment: Marine climate, temperature changes, salt spray corrosion intensity;
Structural requirements: Strength grades and thicknesses required for different parts;
Certification requirements: Does the project require certification from classification societies such as ABS/LR/DNV?
Supply capacity: Can it be custom-sized, cut or heat-treated according to the project?
Summary
Marine steel plate is an indispensable basic material in ships and Marine engineering. Its specifications and performance directly affect the safety and durability of the structure.
When making a selection, particular attention should be paid to the standard grade, mechanical properties and certification system of the steel plate to ensure that it meets the project requirements.
Read more : Classification of shipbuilding plates