Shipbuilding Steel Plate
Shipbuilding Steel Plate Supplier – AH32, AH36, DH36 & EH36
LYH Steel supplies shipbuilding steel plate for hull structures, decks, bulkheads, offshore structures and marine fabrication.
Common grades include A, B, D, E, AH32, DH32, EH32, AH36, DH36 and EH36, with material selection based on strength class, Charpy toughness, plate thickness, delivery condition, welding and classification requirements.
Shipbuilding Steel Plate: Quick Selection Guide
32-class grades such as AH32, DH32 and EH32 provide a lower high-strength level than the corresponding 36-class grades.
36-class grades such as AH36, DH36 and EH36 share essentially the same strength class; the A / D / E prefix primarily differentiates required impact-toughness performance at progressively lower test temperatures.
Do not select EH36 simply because it appears “higher” than AH36. The correct grade must follow the vessel design, structural category, minimum design temperature, plate thickness and classification rules.
What Is Shipbuilding Steel Plate?
Shipbuilding steel plate is structural steel produced and tested for use in ship hulls and related marine structures under applicable material standards and classification rules.
Its procurement requirements can include:
- specified minimum yield and tensile strength,
- Charpy V-notch impact toughness,
- controlled chemical composition and carbon equivalent,
- approved manufacturing route and delivery condition,
- weldability requirements,
- material traceability and certification,
- classification-society survey or approval where required.
Shipbuilding Steel Grades Explained
| Grade Family | What It Indicates | Typical Procurement Question |
|---|---|---|
| A / B / D / E | Ordinary-strength hull structural grades | What strength and impact-test requirements apply at the ordered thickness? |
| AH / DH / EH / FH | Higher-strength hull structural grades with different toughness classes | What impact-test temperature is required? |
| 32 | Approx. 315 MPa minimum yield-strength class | Is 32-class strength sufficient for the approved structure? |
| 36 | Approx. 350–355 MPa minimum yield-strength class depending on governing rule notation / conversion | Does the drawing specify AH36, DH36 or EH36? |
| 40 | Higher-strength class available under applicable rules / specifications | Is the mill and plate thickness approved for the required grade? |
Grade 32 vs Grade 36 Shipbuilding Steel
| Strength Class | Common Grades | Minimum Yield Class | Common Tensile Range |
|---|---|---|---|
| 32 | AH32 / DH32 / EH32 / FH32 | Approx. ≥315 MPa | Approx. 440–590 MPa |
| 36 | AH36 / DH36 / EH36 / FH36 | Approx. ≥350–355 MPa* | Approx. 490–620 MPa |
*ASTM A131/A131M expresses the 36-class minimum as 51 ksi / approximately 350 MPa, while common metric classification rules and grade data are often stated as 355 MPa. The governing specification controls contractual acceptance.
AH36 vs DH36 vs EH36: What Is the Real Difference?
AH36, DH36 and EH36 are broadly in the same 36 strength class. The main procurement difference is the required low-temperature Charpy V-notch toughness level.
| Grade | Strength Class | Typical Charpy Test Temperature | Selection Meaning |
|---|---|---|---|
| AH36 | 36 | 0°C | Higher-strength grade with A-level toughness requirement |
| DH36 | 36 | −20°C | Same strength class, lower-temperature impact requirement |
| EH36 | 36 | −40°C | Same strength class, more demanding low-temperature impact requirement |
| FH36 | 36 | −60°C | More severe low-temperature toughness class where specified |
AH36 → DH36 → EH36 does not mean increasing yield strength. It mainly represents progressively more demanding impact-toughness requirements within the same 36-class strength family.
AH32 vs DH32 vs EH32
The same general logic applies to the 32 strength class.
AH32
32-class high-strength hull steel with A-level toughness requirements.
DH32
Same basic strength class with a more demanding low-temperature impact requirement.
EH32
Same 32 strength class with still lower-temperature Charpy qualification.
Why Charpy Impact Toughness Matters in Shipbuilding
Hull structures experience cyclic loading, wave action, local stress concentration and potentially low operating temperatures.
The Charpy V-notch test is used to evaluate the material's ability to absorb energy during rapid fracture at a specified temperature.
Strength
Controls resistance to yielding and contributes to structural load capacity.
Toughness
Addresses resistance to brittle fracture under dynamic loading and lower-temperature conditions.
Shipbuilding Steel Standards
GB/T 712-2022
Chinese national standard: Structural steel for ship and ocean engineering.
Specify it directly when a Chinese-standard material is required.
ASTM A131/A131M
ASTM specification covering structural steel intended primarily for ship construction.
Includes ordinary- and higher-strength ship structural grades.
IACS UR W11
IACS Unified Requirement for normal- and higher-strength hull structural steels.
Projects must use the revision required by the applicable class rules and contract.
Plate Thickness & IACS W11 Scope
LYH's published commercial range currently extends to approximately 120 mm for this product page, but that does not mean every grade, mill or classification approval automatically covers that full thickness.
IACS UR W11 currently addresses normal- and higher-strength hull structural steels up to 100 mm. IACS has also published Recommendation 197 for steels above 100 mm and up to 200 mm.
Delivery Condition: As-Rolled, Normalized & TMCP
Shipbuilding steel can be supplied in different delivery conditions depending on grade, thickness, mill approval and classification requirements.
As-Rolled / Controlled Rolled
Permitted only where the governing grade, thickness and class rules allow it.
Normalized
Uses heat treatment to develop the required microstructure and mechanical properties.
TMCP
Thermo-mechanical controlled processing combines controlled rolling and cooling to obtain required strength and toughness.
Classification Society Approval: What Buyers Need to Check
Marine projects may require material from manufacturers approved by a specific classification society, such as:
- ABS,
- DNV,
- Lloyd's Register (LR),
- Bureau Veritas (BV),
- China Classification Society (CCS),
- or another project-specified society.
Manufacturer approval is scope-specific. Confirm the actual mill, grade, thickness, production route and approval status for the required classification society before accepting the material.
Mill Approval vs Plate Certification
These are related, but they are not the same statement.
Approved Manufacturer
The mill has been assessed and approved for a defined material / process scope by the classification society.
Specific Plate / Heat
The supplied material must still have the required traceability, inspection, testing and documentation for the specific project.
MTC, Class Certificate & Traceability
For classed shipbuilding projects, the paperwork is part of the product.
| Document / Check | Purpose |
|---|---|
| Mill Test Certificate | Heat chemistry, mechanical properties, grade and traceability |
| Heat Number | Links physical plate to production and test records |
| Charpy Test Results | Confirms required impact performance where applicable |
| Classification Documentation | Confirms class-related inspection / certification scope where required |
| Plate Marking | Maintains grade and traceability through logistics / fabrication |
| Third-Party Inspection | Project-specific independent inspection when required |
See: Quality Inspection .
Welding & Carbon Equivalent
Shipbuilding steels are designed with weldability as an important requirement, but they should not be described simply as “easy to weld” under every thickness and process condition.
Welding procedure development can depend on:
- grade and strength class,
- plate thickness,
- chemical composition,
- carbon equivalent / Pcm where applicable,
- heat input,
- hydrogen level,
- preheat / interpass temperature,
- welding consumable classification,
- required weld-metal toughness,
- classification-society welding requirements.
Does Shipbuilding Steel Resist Seawater Corrosion?
Standard carbon / low-alloy hull structural steel can corrode in seawater.
Its suitability for ship structures comes from its combination of strength, toughness, weldability and controlled quality— not from stainless-steel-like inherent seawater corrosion resistance.
Coating System
Marine paint systems protect hull and tank surfaces according to vessel and service requirements.
Cathodic Protection
Sacrificial anodes or impressed-current systems may form part of the corrosion-control design.
Inspection & Maintenance
Coating condition, corrosion loss and structural integrity require lifecycle inspection.
Shipbuilding Steel Plate Applications
Hull Shell
Side shell, bottom structures and other class-specified hull regions.
Deck Structures
Deck plating and structural members subject to approved scantling design.
Bulkheads
Watertight, structural and internal bulkhead construction.
Container & Bulk Ships
High-strength hull structural applications according to class drawings.
Tankers
Structural steel for vessel areas where the specified grade is approved.
Offshore Structures
Only where the applicable offshore material specification and class rules permit the selected grade.
Thickness, Width & Plate Size
LYH's current published commercial range for this page is approximately:
| Item | Published Range | Procurement Note |
|---|---|---|
| Thickness | 6–120 mm | Actual range varies by grade, mill, standard and class approval |
| Width | 1500–4200 mm | Confirm mill rolling range and finished tolerance |
| Length | Project / mill dependent | Send required cut length or plate list |
Cutting, Bending & Fabrication
Processing should follow the actual grade, thickness, delivery condition and shipyard welding / fabrication specification.
Cutting
Plate can be supplied in mill sizes or processed to project dimensions subject to processing capability.
Bending
Forming radius, orientation, thickness and delivery condition must be considered.
Welding
Welding consumables and procedure qualification must meet base-metal, toughness and classification requirements.
Shipbuilding Plate Inspection
| Inspection Item | What to Verify |
|---|---|
| Material Identity | Grade, heat number, mill and standard |
| Chemistry | MTC values against applicable specification |
| Tensile Test | Yield / tensile / elongation requirements |
| Charpy Impact | Required temperature, orientation and impact energy |
| Dimensions | Thickness, width, length and tolerances |
| Surface Quality | Condition against applicable acceptance requirements |
| UT | Internal soundness when required by class / project |
| Class Documentation | Required manufacturer approval and certificate scope |
Shipbuilding Steel Plate RFQ Checklist
For a classed project, send more than “AH36 price.”
- Grade: AH32, DH32, EH32, AH36, DH36, EH36 or other required grade.
- Standard / class: ASTM A131, GB/T 712, ABS, DNV, LR, BV, CCS or the applicable project rule.
- Required class approval: specify the classification society clearly.
- Thickness: required plate thickness.
- Width and length: plate size or complete cutting list.
- Delivery condition: as required by class / approved drawing.
- Impact requirement: grade, test temperature and any project-specific toughness requirement.
- UT requirement: standard and acceptance class if required.
- Processing: cutting, beveling, bending or other preparation.
- Documentation: MTC, class certificate, inspection documents and traceability requirements.
- Quantity: plate list or total tonnage.
- Destination: port, packing and Incoterm.
Related Steel Plate & Procurement Resources
Technical Reference Notes
GB/T 712-2022
Current Chinese national standard for structural steel for ship and ocean engineering.
ASTM A131/A131M
ASTM structural-steel specification for materials intended primarily for ship construction.
IACS UR W11
Unified Requirement for normal- and higher-strength hull structural steels.
Shipbuilding Steel Plate FAQ
1. What is shipbuilding steel plate?
Shipbuilding steel plate is structural steel produced and tested for ship hulls and marine structures under specified material standards and classification rules.
2. What is the difference between AH36, DH36 and EH36?
They belong to the same general 36 strength class. The major distinction is progressively lower Charpy impact-test temperature: commonly 0°C for AH36, −20°C for DH36 and −40°C for EH36.
3. Is EH36 stronger than AH36?
Not in the sense of a higher strength class. AH36, DH36 and EH36 broadly share the same 36-class yield and tensile requirements. EH36 has a more demanding low-temperature toughness requirement.
4. What is the difference between AH32 and AH36?
AH36 belongs to a higher strength class. AH32 is approximately a 315 MPa minimum-yield class, while AH36 is approximately a 350–355 MPa minimum-yield class, depending on the governing specification.
5. Is shipbuilding steel corrosion resistant?
Conventional hull structural steel is not inherently seawater-corrosion-proof. Coatings, cathodic protection, inspection and maintenance normally form part of the vessel's corrosion-control system.
6. Does every AH36 plate have ABS, DNV, LR, BV and CCS certification?
No. Classification approval depends on the actual manufacturer, approved product scope, grade, thickness, manufacturing route and project documentation. The required society should be specified before purchase.
7. What is TMCP shipbuilding steel?
TMCP means thermo-mechanical controlled processing. It uses controlled rolling and cooling to achieve required strength and toughness. Its use must match the approved grade, thickness and classification requirements.
8. Can AH36 steel be welded?
Yes. AH36 is widely used in welded ship structures, but the welding procedure, filler metal, heat input and toughness requirements must match the material and classification rules.
9. What documents should come with shipbuilding plate?
Depending on the contract, documentation may include the Mill Test Certificate, heat-number traceability, mechanical and Charpy test results, and classification-society documentation where required.
10. What information is required for a ship plate quote?
Send grade, standard or class society, thickness, width, length, quantity, delivery condition, impact requirement, UT requirement, processing, certification and destination.
Order Shipbuilding Plate by Grade + Toughness + Class
A complete shipbuilding-plate RFQ needs more than “AH36 steel plate.”
The correct purchasing definition is: grade + standard + classification society + thickness + impact requirement + delivery condition + inspection + certification.