Products FAQ
What is the difference between DNV DH32 and DNV AH32 marine steel?
DNV DH32 marine steel has better low-temperature toughness (-20°C) than DNV AH32 marine steel and is suitable for colder waters and marine structures subjected to higher loads, while DNV AH32 is more suitable for traditional coastal shipbuilding projects.
Does your company offer custom specifications for its DNV Grade DH32 shipbuilding steel plates?
Yes. We can customize thickness, dimensions, and surface treatment based on customer drawings and project requirements, and we also provide precision cutting and machining services.
Do you supply DNV Grade DH32 shipbuilding steel plates certified for export?
Yes. All of our DNV Grade DH32 shipbuilding steel plates are DNV-certified and come with complete Material Test Certificates (MTCs) and certification documents, supporting global exports and third-party inspections (SGS, BV, etc.).
What is the weldability of DNV Grade AH36 steel?
DNV Grade AH36 steel has excellent weldability; however, preheating conditions and process parameters must be strictly controlled during actual welding. The specific points are as follows:
1. Preheating Requirements
For fillet and butt welds with plate thicknesses > 30 mm, the preheating temperature before welding should be 120 - 150 °C;
For plate thickness ≤ 30 mm and ambient temperatures below 5 °C, the preheating temperature should not be lower than 75 °C.
2. Common Welding Methods
Conventional arc welding processes such as Shielded Metal Arc Welding (SMAW), Submerged Arc Welding (SAW), and Flux-Cored Arc Welding (FCAW) are recommended.
3. Welding Quality
Relevant studies indicate that, under appropriate welding procedure specifications (WPS), the impact toughness of all regions (weld, fusion zone, and heat-affected zone) in DNV Grade AH36 welded joints meets the requirements of classification society regulations, demonstrating good process adaptability.
What are the differences between NV A36, NV D36, and NV E36 shipbuilding steel plates?
The key differences between these three types of shipbuilding steel plates lie in their low-temperature impact toughness and applications:
| Grade | Yield Strength | Tensile Strength | Impact Test Temperature | Applications |
|---|---|---|---|---|
| NV A36 | ≥ 355 MPa | 490–630 MPa | 0°C | Coastal vessels, decks, superstructures, mild-temperature waters |
| NV D36 | ≥ 355 MPa | 490–630 MPa | -20°C | Vessels in cold regions, hull bottoms, bulkheads |
| NV E36 | ≥ 355 MPa | 490–630 MPa | -40°C | Arctic vessels, offshore platforms, low-temperature marine structures |
Note: Do not substitute grades arbitrarily; adhere to DNV design temperature requirements.
Do you offer custom processing for marine steel plates?
Yes, we provide a range of value-added services, including cutting, bending, drilling, rust removal, and painting, and can customize dimensions and processing solutions based on customer drawings and project requirements.
Do you provide certified MTC documents for DNV Grade AH36 shipbuilding stee plates?
Yes. We provide MTC compliant with DNV standards for each batch of products, which support third-party inspection.
What is the difference between DNV Grade AH36 and DNV Grade DH36 shipbuilding steel plates?
Both are high-strength structural steel plates for shipbuilding with a yield strength of at least 355 MPa, in compliance with DNV regulations. The key difference lies in the minimum service temperature:
AH36: Design operating temperature ≥ 0°C, impact test temperature 0°C; suitable for warm waters.
DH36: Offers superior low-temperature toughness, with an impact test temperature of -20°C, and is suitable for cold waters.
Is DNV Grade AH32 shipbuilding steel plate weldable?
Yes. Its low carbon equivalent ensures good weldability, making it suitable for manual metal arc welding (SMAW), submerged arc welding (SAW), gas metal arc welding (GMAW), and flux-cored arc welding (FCAW). Welding procedures should be carried out in accordance with the relevant DNV welding codes.
What are the differences between DNV AH32 and equivalent steel grades from other classification societies (ABS / CCS / BV / LR)?
DNV AH32 is similar to ABS AH32, CCS AH32, BV AH32, and LR AH32 in terms of basic chemical composition and mechanical properties. The main differences lie in the following three aspects:
1. Different certifying classification societies: They are recognized by different classification societies, including DNV, ABS, CCS, BV, and LR.
2. Different inspection standards: There are variations in the specific inspection codes and testing requirements of each classification society.
3. Different certificates and scope of application: The flag states, classification requirements, and project locations covered by the certification certificates of different classification societies may vary.
Engineering Application Recommendations
These steel grades are generally interchangeable under normal operating conditions; however, in actual applications, the requirements of the project-designated classification society must be strictly adhered to.
