Applications of DNV Grade AH32 Shipbuilding Steel Plates in Commercial Ships and Offshore Engineering
- Jun 15, 2026
Knowledge
Differences Between DNV Grade AH32 and DH32 and EH32
I. Comparison of Mechanical Properties
| Properties | DNV Grade AH32 (NV A32) | DNV Grade DH32 (NV D32) | DNV Grade EH32 (NV E32) |
|---|---|---|---|
| Yield Strength, ReH | ≥ 315 MPa | ≥ 315 MPa | ≥ 315 MPa |
| Tensile Strength, Rm | 450 - 570 MPa | 450 - 570 MPa | 450 - 570 MPa |
| Impact Temperature | 0 ℃ | - 20 ℃ | - 40 ℃ |
| Impact Energy (Longitudinal) | ≥ 31 J | ≥ 31 J | ≥ 31 J |
| Elongation | ≥ 22 % | ≥ 22 % | ≥ 22 % |
Key Differences:
DNV Grade AH32: With an impact test temperature of 0°C, this grade is suitable for ambient and mildly cold marine environments and is the most cost-effective basic grade of high-strength ship plate.
DNV Grade DH32: Impact test temperature is -20°C. It offers stable low-temperature toughness and superior resistance to low-temperature brittle fracture compared to AH32.
DNV Grade EH32: Impact test temperature is -40°C. It features exceptional low-temperature toughness and is suitable for extremely cold waters and harsh operating conditions.
II. Comparison of Chemical Composition
| Elements | DNV Grade AH32 (NV A32) | DNV Grade DH32 (NV D32) | DNV Grade EH32 (NV E32) |
|---|---|---|---|
| C | ≤ 0.18 | ≤ 0.18 | ≤ 0.18 |
| Si | ≤ 0.50 | ≤ 0.50 | ≤ 0.50 |
| Mn | 0.90 - 1.60 | 0.90 - 1.60 | 0.90 - 1.60 |
| P | ≤ 0.030 | ≤ 0.025 | ≤ 0.025 |
| S | ≤ 0.030 | ≤ 0.025 | ≤ 0.025 |
| Cu | ≤ 0.35 | ≤ 0.35 | ≤ 0.35 |
| Cr | ≤ 0.20 | ≤ 0.20 | ≤ 0.20 |
| Ni | ≤ 0.40 | ≤ 0.40 | ≤ 0.40 |
| Nb | 0.02 - 0.05 | 0.02 - 0.05 | 0.02 - 0.05 |
| V | 0.05 - 0.10 | 0.05 - 0.10 | 0.05 - 0.10 |
| Ti | ≤ 0.02 | ≤ 0.02 | ≤ 0.02 |
| Mo | ≤ 0.08 | ≤ 0.08 | ≤ 0.08 |
| Als | ≥ 0.015 | ≥ 0.015 | ≥ 0.015 |
Key Differences:
Compared to DNV AH32, DNV DH32 and EH32 impose stricter limits on the content of the harmful elements phosphorus (P) and sulfur (S).
III. Comparison of Delivery Conditions and Processing Methods
| Grade | DNV Grade AH32 (NV A32) | DNV Grade DH32 (NV D32) | DNV Grade EH32 (NV E32) |
|---|---|---|---|
| Delivery Conditions | HR, CR, TMCP, N (thickness ≥ 50 mm) | TMCP, N or Q+T (thickness ≥ 50 mm) | TMCP, N, Q+T |
IV. Comparison of Application Scenarios
| Grade | Suitable Environment | Typical Applications |
|---|---|---|
| DNV Grade AH32 (NV A32) | Temperate / Offshore | Decks, bulkheads, inner bottoms, general offshore platforms, cost-sensitive projects |
| DNV Grade DH32 (NV D32) | Winter / Cold-water regions (North Pacific, North Atlantic) | Hull sides / bottom outer plates, offshore platform jackets |
| DNV Grade EH32 (NV E32) | Polar / Cryogenic Environments (Arctic research vessels, LNG carriers, ice-class vessels) | Cold-water offshore structures |
V. Summary of Key Differences
Low-temperature toughness: EH32 (-40°C) > DH32 (-20°C) > AH32 (0°C)
Composition control: Grade E is the strictest (lower P and S content), followed by Grade D, with Grade A being the least stringent
Processing cost: EH32 > DH32 > AH32 (Grade E requires more complex heat treatment and inspection)
Operating temperature: Grade A ≥ 0°C, Grade D ≥ -20°C, Grade E ≥ -40°C
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