Choosing the right steel grade is a critical decision in shipbuilding and offshore engineering. Among the commonly used grades under the ASTM A131 standard, AH32, AH36, and AH40 steel plates stand out for their balance of strength, toughness, and weldability. While all belong to the same family, their differences in mechanical properties, equivalent standards, and applications make each grade suitable for specific project needs.
For steel distributors, traders, and shipbuilding procurement managers, selecting the right grade isn't just about technical specs-it's about balancing cost, availability, and project requirements to maximize value and ensure on-time delivery.
Specifications and Certifications
When sourcing AH series steel, the mill certificate from a recognized classification society (ABS, LR, DNV, etc.) is not optional-it's mandatory. It is your guarantee that the material meets the stringent safety and quality standards for marine service. Always request and verify the EN 10204 3.1/3.2 certificate with your order.
In real-world supply, shipbuilding plates are usually available in:
Thickness: 6–100 mm (heavier sections may be rolled to order)
Width: 1500–3000 mm
Length: up to 12,000 mm or customized
For international projects, these steels are generally supplied with classification society certificates such as:
ABS, LR, DNV, BV, RINA, NK
These certifications ensure compliance with global shipbuilding requirements.
What is AH32 Steel?
AH32 steel is a mild-strength shipbuilding steel grade widely used for hull structures and general ship construction.
Key Properties of AH32 Steel:
Yield Strength: ≥ 315 MPa
Tensile Strength: 440–590 MPa
Density: ~7.85 g/cm³
Equivalent Standards: EN S275, DIN St44, JIS E32.
Typical Applications: Small and medium-sized vessels, ferryboats, and deck structures in moderate sea conditions.
What is AH36 Steel?
AH36 steel is a high-strength grade with better performance than AH32, offering improved toughness and wider usage in larger vessels.
Key Properties of AH36 Steel:
Yield Strength: ≥ 355 MPa
Tensile Strength: 490–620 MPa
Density: ~7.85 g/cm³
Common Equivalents: EN S355, LR AH36, DNV AH36.
Typical Applications: Cargo ships, bulk carriers, offshore wind towers, and other heavy marine structures.
What is AH40 Steel?
AH40 steel belongs to the extra-high-strength category, designed for demanding offshore and deep-sea projects. It offers higher yield strength compared to AH32 and AH36.
Key Properties of AH40 Steel:
Yield Strength: ≥ 390 MPa
Tensile Strength: 510–650 MPa
Excellent toughness at low temperatures
Equivalent Grades: EN S420, LR AH40, RINA AH40.
Typical Applications: Large container ships, oil tankers, LNG carriers, offshore oil & gas platforms, and naval vessels.
AH32 vs AH36 vs AH40: Key Differences
| Grade | Yield Strength (MPa) | Tensile Strength (MPa) | Typical Applications | Procurement & Sourcing Advice |
|---|---|---|---|---|
| AH32 | ≥ 315 | 440–590 | Small vessels, ferries, general hull structures | Best for cost-sensitive projects. High market availability, fast delivery on standard sizes. Ideal for distributors targeting small to medium shipyards. |
| AH36 | ≥ 355 | 490–620 | Cargo ships, bulk carriers, offshore structures | The most balanced and widely used grade. Maintain high stock levels. Highest demand from global cargo ship and carrier projects. |
| AH40 | ≥ 390 | 510–650 | Tankers, LNG carriers, offshore platforms | For specialized, high-value projects. Longer lead times may apply for thick plates. Confirm certification (e.g., offshore standards) with supplier early. |
- Strength ranking: AH40 > AH36 > AH32
- Applications: Higher grades are preferred for harsher environments and larger vessels.
- Cost considerations: In practice, AH36 is about 8–12% more expensive than AH32, while AH40 can be 15–20% higher, reflecting its superior performance.
Applications in Shipbuilding and Offshore Engineering
- AH32: Fishing boats, ferries, small cargo vessels
- AH36: Bulk carriers, container ships, offshore wind towers
- AH40: LNG carriers, super tankers, naval ships, offshore drilling platforms
With the growing demand for offshore energy projects and larger, more fuel-efficient vessels, higher-strength grades like AH36 and AH40 are increasingly in demand.
👉 If you are looking for detailed specifications, stock availability, and delivery options of these grades, please check our AH32, AH36, and AH40 Shipbuilding Steel Plates product page.
Sourcing AH32, AH36, AH40 Steel: Key Supplier Qualifications
Stock & Lead Time: A reliable supplier maintains a wide range of products in stock, with fast cutting and delivery services.
Certification Expertise: Supply with all major classification society certificates, ensuring your project passes audits smoothly.
Global Logistics: Experienced in exporting to shipbuilding hubs in Asia, Europe, and the Middle East.
Technical Support: Help you navigate grade selection and certification requirements.
Conclusion
While AH32, AH36, and AH40 steel plates belong to the same ASTM A131 family, their differences in strength and toughness make them suitable for different levels of structural demand.
- AH32 offers cost-effectiveness for moderate conditions.
- AH36 strikes a balance between performance and price for most global shipping needs.
- AH40 is designed for challenging offshore environments and heavy-duty applications.
For shipbuilders and project managers, understanding these distinctions helps in selecting the right grade for long-term reliability and efficiency.
As a specialist in marine and offshore steel plates, we supply AH32, AH36, and AH40 with full certification (ABS, LR, DNV, etc.). Contact us today for a competitive quote, current stock list, or to discuss your project's specific requirements.
What is the difference between AH32 and AH36?
AH36, H represents high strength, 36 represents 360MPa, A represents the grade of steel, which can be divided into 4 grades (A, B, D, E). This meaning represents high-strength Grade A marine steel with an allowable pressure of 360MPa. AH32 is high-strength A-grade marine steel with a required pressure of 320MPa.
What is AH-36 steel?
AH36 is designed to resist the harsh saline conditions of marine environments, and micro-alloying technology is employed to enhance performance. Elements such as Nb, V, Ti, and other alloying metals, combined with a controlled rolling process, refines the grain and improves the toughness.
What is the yield strength of grade AH36?
ABS AH36: Has a minimum yield strength of 51,000 psi (355 MPa) and a minimum tensile strength of 71,000 – 90,000 psi (490-620 MPa).
What is AH32 steel?
ABS Grades AH32, DH32, and EH32 are higher-strength structural steels with a minimum specified yield strength of 46 ksi and specified minimum Charpy V- notch impact toughness properties. Applications. Typical applications include shipbuilding and mobile offshore drilling units and structures.
What is the difference between A36 and AH36 steel?
In this condition, ASTM AH36 steel and A36 steel is totally the same. However, at most times, ASTM A36 steel means another steel type, it is A36 mild steel. A36 mild steel is for general construction, seldom used for ship building. A36 mild steel strength is lower than ASTM AH36 shipbuilding steel strength.
| Other steel plate by GNEE | ||||
| Name | Material | Specification (mm) | Tons | Remark |
| Clad steel plate | P265GH+410,S355JR+410,A516Gr70+316, A537CL1+304L,Q235B+304L,Q345B+304, A516Gr70(NACE)+410,A537CL1+904L, A537CL1+316L,A516Gr70+304L,A537CL1+304 ,A516Gr70+410,A516Gr70+904L |
2-300mm(Based plate),1-50mm(Composited plate) | / | UT, AR, TMCP.Normalized, Quenched and Tempered,Z Direction Test, Charpy V-Notch impact TestThe Third Party Test , Coated or Shot Blasting and Painting. |
| Low Alloy | Q345A, Q345B, Q345C, Q345D, Q345E, Q390, Q420, Q460C, ST52-3, S355J2+N, SS400, SA302GrC, S275NL, 35CrMo | 6 - 350 | 5788.56 | Normalizing, tempered ,controlled rolling, hot rolling , Hot rolling,1st inspection, 2nd inspection, 3rd inspection |
| Pressure Vessel Plate | A204 Grade B,A515 Grade 70,A537 Class 1,SA387 Grade 11 Class 1,P265GH,S537 Class 2,P355Q,P275N,P355N,P690Q,Q345R, | 3 - 300 | 8650 | Normalizing, tempered ,controlled rolling, hot rolling , Hot rolling,1st inspection, 2nd inspection, 3rd inspection |
| High-Strength Plate | A514 Grade F, A572 Grade 50, A588 Grade A, S355JR, S690Q, SS400, S690QL, Q345B, Q345E | 8 - 120 | 3086.352 | Quenched and tempered |
| Wear-Resistant Plate | NM360, NM400, NM450, NM500 | 6 - 150 | 3866.297 | Quenched and tempered |
| Ship Plate | ABS AH32,ABS DH32,ABS EH32,ABS FH36,ASTM A131 A, ASTM A131 EH32,ASTM A131 AH36,CCS A,CCS AH32,LR AH32, DNV A36,BV AH32 |
8 - 200 | 2853.621 | Hot rolling, normalized ,hot rolling controlled rolling, quenched and tempered + toughness and brittleness |
