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DNV Grade B Shipbuilding Steel Plate - DNV Certified Marine Structural Steel

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DNV Grade B shipbuilding steel plates are ordinary-strength marine structural steel plates certified by Det Norske Veritas (DNV) and are widely recognized and used in the global shipbuilding and offshore engineering industries. The DNV Grade B marine steel plates supplied by our company come with complete DNV certification and are available in a full range of dimensions and specifications. We also offer customized heat treatment processes to meet specific requirements. All products undergo rigorous testing to ensure they meet the structural strength requirements for ships and offshore platforms, serving shipyards, offshore platform projects, and marine engineering operations worldwide.

Certification :
DNV Rules
Grade :
DNV Grade B (NV B)
Thickness :
5.0 - 150.0 mm
Width :
1500.0 - 4000.0 mm
Length :
6000.0 - 18000.0 mm

Special thickness, width, and length can be negotiated separately.
We also provide customized processing services.If you have any questions, please contact us.

Overview

1. What is DNV Grade B shipbuilding steel plate?

DNV Grade B shipbuilding steel plate is a ordinary-strength marine structural steel plate certified by DNV (Det Norske Veritas). It is one of the most cost-effective and versatile grades in DNV’s ordinary-strength marine steel series, offering excellent structural strength, weldability, ductility, and consistent room-temperature impact toughness. It is primarily used in areas of the ship’s hull structure subject to lower stress or as a secondary structural material.

2. Meaning of the Designation

NV: Certified by the Det Norske Veritas (DNV)

B: Quality grade B (requiring impact toughness at 0°C)

Available Specifications and Dimensions

Product	DNV Grade B Shipbuilding Steel Plate
Certification	DNV
Grade	NV B
Classification	Ordinary-Strength Structural Steel for Ship and Ocean Engineering
Thickness	5 - 150 mm
Width	1500 - 4000 mm
Length	6000 - 18000 mm
Delivery Conditions	Hot Rolled (HR), Controlled Rolled (CR), Normalized (N), Thermo-Mechanical Controlled Processed (TMCP), Quenched and Tempered (Q+T).
Surface Conditions	The surface is in its original condition; surface treatments such as sandblasting, rust removal, oiling and painting are available.
Testing	Tensile test, Charpy V-notch impact test, Ultrasonic testing (UT), Z-direction property test (Grades Z15/Z25/Z35), dimensional inspection.
Applications	Primarily used for the main hulls, decks, and auxiliary structures of ships in non-arctic waters, as well as components of offshore platforms.
MOQ	5 tons (small orders can be negotiated).
Delivery Time	15 - 20 days after order confirmation (urgent orders accepted)
Packaging	Standard export packaging for sea transport, or as required.
Country of origin	China

Chemical Composition

Chemical Composition (Heat Analysis, wt %)

Grade	C	Si	Mn	P	S	Cu	Cr	Ni	Als
NV B	≤ 0.21	≤ 0.35	≥ 0.80	≤ 0.035	≤ 0.035	≤ 0.35	≤ 0.30	≤ 0.30	-

Carbon Equivalent (wt %)

Thickness (mm)	5 - 50	50 - 150
Typical CEV (wt %)	≤ 0.38	≤ 0.40

Calculation formula (IIW): CEV = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15

Mechanical Properties

Tensile test

Grade	Yield Strength (ReH), MPa	Tensile Strength (Rm), MPa	Elongation (A), %
NV B	≥ 235	400 - 520	≥ 22

Charpy (V-notch) impact test

Grade	Thickness, mm	Temperature, ℃	Impact Energy, KV₂ / J
Grade	Thickness, mm	Temperature, ℃	Longitudinal	Transverse
NV B	≤ 50	0	≥ 27	≥ 20
	> 50 - 70	0	≥ 34	≥ 24
	> 70 - 150	0	≥ 41	≥ 27

Applications

DNV Grade B shipbuilding steel plates are widely used in the construction and repair of vessels operating in conventional waters (operating temperature approximately 0°C), covering the main hull structure, decks, bulkheads, hull plates, and superstructures; they are also suitable for offshore engineering structures such as offshore platforms, jackets, and port machinery.

Typical applications include:

1. Primary hull structures, side plates, decks, and bulkhead plates for commercial vessels.

2. Structural construction of small and medium-sized vessels such as fishing boats and yachts.

3. Auxiliary ship structures, platform supports, and hull reinforcement components.

4. Auxiliary structures, pipe fittings, and ancillary facilities for offshore drilling platforms.

5. Port and marine equipment, floating facilities, and conventional marine engineering structural components.

6. Partial hull replacement and reinforcement during routine shipyard maintenance.

Other Information

Key Features and Advantages

Our DNV Grade B shipbuilding steel plates strictly adhere to official DNV specifications and have been certified by DNV. They offer stable and superior overall performance, effectively addressing key issues such as insufficient toughness, welding difficulties, and poor corrosion resistance in marine structural steel.

1. Certification and Compliance

Fully certified by DNV, all products undergo rigorous factory inspections and comply with international shipbuilding industry standards, supporting project acceptance at shipyards worldwide.

2. Reliable Room-Temperature Toughness

Verified through standardized 0°C impact tests, the steel exhibits excellent impact resistance, effectively withstanding marine wave impacts, structural vibrations, and dynamic loads, thereby reducing the risk of structural cracking.

3. Superior Structural Strength

Features stable yield and tensile strengths, uniform internal grain structure, and excellent pressure resistance and load-bearing capacity, making it suitable for long-term, complex marine loading conditions.

4. Outstanding Processability

Offers excellent weldability, cutting, and bending properties. Easy to process, facilitating the forming and welding of various ship structures and significantly improving shipbuilding efficiency.

5. Good Marine Corrosion Resistance

Featuring an optimized chemical composition design (low carbon equivalent), it offers a certain level of resistance to atmospheric and seawater corrosion, reducing oxidation and corrosion damage in offshore and marine service environments.

6. Consistent Quality

Strict control of chemical composition and mechanical properties ensures no lamination defects and uniform plate thickness. Consistent quality in bulk supply meets the requirements for large-scale procurement in major shipbuilding projects.

7. Customizable Heat Treatment Processes

Supports rolling, controlled rolling, TMCP, and normalizing heat treatment. For steel plates thicker than 40 mm, normalizing is recommended to enhance structural stability and eliminate internal stresses.

Our Advantages and Service Guarantees

As a specialized supplier of DNV Grade B shipbuilding steel plates, we offer long-term, stable supply capabilities and a comprehensive after-sales service system.

1. Full DNV Certification

All products are certified by DNV and come with complete test reports, certificates, and inspection documents.

2. Strict Quality Control

Every batch of steel plates undergoes chemical composition analysis, mechanical property testing, and impact testing to ensure 100% compliance with DNV standards.

3. Excellent Value for Money

Direct factory sourcing, ample inventory, stable pricing, and rapid delivery.

4. Global Delivery Capabilities

Extensive experience in international logistics, timely delivery, complete export documentation, and support for international trade terms such as FOB, CIF, and CFR.

5. One-Stop Service

We provide integrated services including custom processing, packaging, logistics, and after-sales support to meet customers’ specific needs and effectively reduce procurement costs.

FAQ

Q1:

In shipbuilding, where is DNV Grade B steel plate primarily used?

It is primarily used for the main structures of vessels under 10,000 tons, or for secondary and non-critical structures of general strength on large vessels (such as superstructures, internal bulkheads, deck platforms, etc.). Since it is designed for operating environments above 0°C, it is well-suited for the construction of ships, barges, and certain coastal fishing vessels intended for operation in coastal, inland waterway, and temperate non-ice-bound waters.

Q2:

What certifications are required for DNV Grade B shipbuilding steel plates?

The product must hold a valid DNV factory certification (3.1 or 3.2 certificate) and have full traceability. If required for use across classification societies, certifications from ABS, LR, CCS, etc., may also be provided. Third-party inspections (such as SGS or BV) can be provided upon customer request.

Q3:

Can DNV Grade B shipbuilding steel plates be used for offshore oil and gas platforms?

Yes, DNV Grade B shipbuilding steel plates are widely used for secondary structural components in offshore platforms and barges. However, for primary, heavy-duty, or polar environments, high-strength shipbuilding steel plates such as DNV AH32, AH36, DH32, DH36, EH32, and EH36 are typically preferred.

Q4:

What is the main difference between DNV Grade A shipbuilding steel plates and DNV Grade B shipbuilding steel plates?

The main difference lies in the impact toughness requirements. DNV Grade A shipbuilding steel plates do not require mandatory impact testing for plates with a thickness of ≤50 mm (or testing at room temperature). In contrast, DNV Grade B steel plates must undergo mandatory Charpy V-notch impact testing at 0°C to ensure higher structural safety in colder marine climates.

Q5:

Does DNV Grade B shipbuilding plate require heat treatment?

Standard thin plates can be supplied in the as-rolled condition; however, for plates thicker than 40 mm, it is recommended to use the normalized delivery condition to refine the grain structure, eliminate internal stresses, and improve the toughness and weldability of the thick plate.