Comparison of Properties and Selection of ABS AH32 / DH32 / ...
- May 07, 2026
Knowledge
Comparison of Properties and Selection of ABS AH32 / DH32 / EH32 High-Strength Shipbuilding Steel Plates
I. Key Definitions and Naming Conventions
A / D / E: Denote impact test temperatures of 0°C, -20°C and -40°C respectively
H: High Strength
32: Minimum yield strength 315 MPa
II. Comparison of Chemical Composition (wt%, typical values)
| Grade | C | Si | Mn | P | S | Als |
|---|---|---|---|---|---|---|
| ABS AH32 | ≤ 0.18 | ≤ 0.50 | 0.90 - 1.60 | ≤ 0.030 | ≤ 0.030 | ≥ 0.015 |
| ABS DH32 | ≤ 0.18 | ≤ 0.50 | 0.90 - 1.60 | ≤ 0.025 | ≤ 0.025 | ≥ 0.015 |
| ABS EH32 | ≤ 0.18 | ≤ 0.50 | 0.90 - 1.60 | ≤ 0.025 | ≤ 0.025 | ≥ 0.015 |
Key differences: Grade DH32 and EH32 impose stricter controls on phosphorus (P) and sulphur (S) content to enhance low-temperature toughness and resistance to brittle fracture.
III. Comparison of Mechanical Properties
| Grade | Yield Strength (ReH), MPa | Tensile Strength (Rm), MPa | Elongation (A), % | Impact Temperature | Impact Energy, KV2 / J |
|---|---|---|---|---|---|
| ABS AH32 | ≥ 315 | 450 - 570 | ≥ 22 | 0 ℃ | 31 |
| ABS DH32 | ≥ 315 | 450 - 570 | ≥ 22 | -20 ℃ | 31 |
| ABS EH32 | ≥ 315 | 450 - 570 | ≥ 22 | -40 ℃ | 31 |
Key difference: The impact temperature at low temperatures decreases progressively, whilst low-temperature toughness increases accordingly.
IV. Comparison of Weldability
| Grade | Weldability | Key Requirements |
|---|---|---|
| AH32 | Good | Thickness ≤20 mm; preheating generally not required |
| DH32 | Good | Thickness >50 mm; preheating required at 120–150°C |
| EH32 | Good | Thick plates require preheating + post-weld heat treatment |
V. Suitable Environments and Typical Applications
| Grade | Suitable Environment | Typical Applications |
|---|---|---|
| AH32 | Warm waters (≥0°C) | Inland waterways, coastal waters, South China Sea, Southeast Asia, small vessels |
| DH32 | Mid-to-high latitude winter waters (≥ -20°C) | Ocean-going vessels, Yellow Sea, East China Sea, Mediterranean Sea, conventional offshore platforms |
| EH32 | Extremely cold waters (≥ -40°C) | Arctic, icebreakers, polar platforms, low-temperature high-stress structures |
VI. Selection Recommendations
| Condition | Recommended Grade | Reason |
|---|---|---|
| 80% of ocean-going vessels and offshore engineering | DH32 | Best value for money; toughness at -20°C covers most routes |
| Warm waters (e.g. South China Sea) | AH32 | Meets toughness requirements, lower cost |
| Extremely cold waters (e.g. Arctic) | EH32 | Toughness at -40°C ensures safety |
| Plate thickness >50 mm | DH32 (Z25/Z35) | Balances low-temperature toughness and resistance to laminar tearing |
Summary
AH32, DH32 and EH32 share the same strength grade (yield strength ≥ 315 MPa), with the core difference lying solely in their low-temperature impact temperatures. Thanks to its -20°C toughness, good weldability and moderate cost, DH32 has become the mainstream choice for ocean-going vessels and offshore engineering projects in medium-to-low temperature waters. Actual selection should strictly align with the minimum ambient temperature, structural stress levels and welding process requirements.
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