NK Hull Structure Plate

NK Hull Structure Plate

NK Hull Structure Plate is a high-quality steel plate that has been certified by Nippon Kaiji Kyokai (ClassNK) for use in building a ship's hull.

 

NK can be divided into:

General strength ship plating: A, B, D, E.

High-strength ship plates: AH32, AH36, AH40, DH32, DH36, DH40, EH32, EH36, EH40, FH36 and ultra-high-strength ship plates DH460, EH460, EH550, EH690, etc.

 

GNEE steel also has a pre-treatment process line can offer our clients shot blasting and shop primed service on NK AH36 shipbuilding steel hull structure plates. Blasting is according to SA2.5 standard, and the coating thickness of the shop primer painting is 20 micrometers or so for NK AH36 shipbuilding steel hull structure plates.

 

Clients can be never worried about GNEE NK AH36 shipbuilding steel hull structure plate quality, not only because of the quality-controlling from the NK classification society , but also from our steel mill. BBN steel offers Mill Test Certificate, whose information can match the HARD stamp on the NK AH36 shipbuilding steel hull structure plates by brand of manufacturer, Heat No., Batch No., steel grade, steel size, and the brand of Classification Society.

 

 

NK Steel Plate Grade
General Strength	K A	K B	K D	K E
High Strength	K A32	K D32	K E32	K F32
	K A36	K D36	K E36	K F36
	K AH40	K DH40	K EH40	K F40
Extra Strength	K A43	K D43	K E43	K F43
	K A47	K D47	K E47	K F47
	K A51	K D51	K E51	K F51
	K A56	K D56	K E56	K F56
	K A63	K D63	K E63	K F63
	K A70	K D70	K E70	K F70
	K A63N	K D63N	K E63N	K F63N
	K A70N	K D70N	K E70N	K F70N

 

 

Grade	Thickness(mm)	MinYield(Mpa)	Tensile(Mpa)	Elongation (%)	Min Impact Energy
NK Grade AH32	8mm-50mm	Min 315Mpa	440-590Mpa	22%	-	34J
	51mm-70mm	Min 315Mpa	440-590Mpa	22%	-	38J
	71mm-100mm	Min 315Mpa	440-590Mpa	22%	-	46J
The min impact energy is longitudinal energy

 

Grade	Thickness(mm)	MinYield(Mpa)	Tensile(Mpa)	Elongation (%)	Min Impact Energy
NK Grade EH32	8mm-50mm	Min 315Mpa	440-590Mpa	22	-40	34J
	51mm-70mm	Min 315Mpa	440-590Mpa	22	-40	38J
	71mm-100mm	Min 315Mpa	440-590Mpa	22	-40	46J
The minimum impact energy is longitudinal energy

 

Grade	Thickness(mm)	MinYield(Mpa)	Tensile(Mpa)	Elongation (%)	Min Impact Energy
NK Grade AH36	8mm-50mm	Min 355Mpa	490-620Mpa	21%	-0	34J
	51mm-70mm	Min 355Mpa	490-620Mpa	21%	-0	41J
	71mm-100mm	Min 355Mpa	490-620Mpa	21%	-0	50J
The min impact energy is longitudinal energy

 

Grade	Thickness(mm)	MinYield(Mpa)	Tensile(Mpa)	Elongation (%)	Min Impact Energy
NK Grade EH36	8mm-50mm	Min 355Mpa	490-620Mpa	21%	-40	34J
	51mm-70mm	Min 355Mpa	490-620Mpa	21%	-40	41J
	71mm-100mm	Min 355Mpa	490-620Mpa	21%	-40	50J
The min impact energy is longitudinal energy

 

Grade	Thickness(mm)	MinYield(Mpa)	Tensile(Mpa)	Elongation (%)	Min Impact Energy
NK Grade AH40	8mm-50mm	Min 390Mpa	510-650Mpa	20%	0	34J
	51mm-70mm	Min390Mpa	510-650Mpa	20%	0	41J
	71mm-100mm	Min 390Mpa	510-650Mpa	20%	0	50J
The min impact energy is longitudinal energy

 

Grade	Thickness(mm)	MinYield(Mpa)	Tensile(Mpa)	Elongation (%)	Min Impact Energy
NK Grade EH40	8mm-50mm	Min 390Mpa	510-650Mpa	20%	-40	34J
	51mm-70mm	Min390Mpa	510-650Mpa	20%	-40	41J
	71mm-100mm	Min 390Mpa	510-650Mpa	20%	-40	50J
The min impact energy is longitudinal energy

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Key Advantages of NK Hull Structure Plate

 

1. Strict NK Certification & Global Compliance

NK Hull Structure Plates are certified by Nippon Kaiji Kyokai, ensuring full compliance with international marine classification standards. They can also meet multi-class approvals (ABS, LR, DNV, CCS), making them suitable for global shipbuilding projects.

 

2. Guaranteed Low-Temperature Toughness of NK Hull Structure Plate

The ability to absorb energy without fracturing at sub-zero temperatures is a non-negotiable property of a true NK Hull Structure Plate. Our KD, KE, and all EH series plates undergo rigorous Charpy V-notch impact testing at temperatures as low as -40°C. This verified toughness is critical for vessels navigating icy Northern Sea Routes or carrying cryogenic LNG cargo. GNEE achieves this through strict control of inclusion cleanliness and by administering a fine-grain rolling practice that eliminates the brittle transition ductility trough, delivering material that stays reliable in the most unforgiving cold environments.

 

3. Excellent Weldability & Fabrication Performance

With low carbon equivalent (CEV), these plates minimize cracking risks during welding and support efficient fabrication processes such as cutting, bending, and forming-reducing production time and cost.

 

4. High Strength with Weight Optimization

High-strength grades like AH36, DH36, and EH36 allow shipbuilders to reduce plate thickness without compromising structural integrity, resulting in lighter vessels and improved fuel efficiency.

 

5. Superior Fatigue and Corrosion Resistance

A vessel's lifecycle cost is directly linked to how well its steel resists the daily grind of wave-induced cyclic stress and seawater corrosion. The internal homogeneity and smooth surface finish of our NK Hull Structure Plate significantly reduce initiation points for pitting corrosion and fatigue cracks. This is particularly advantageous in high-stress zones like tank corners, side longitudinals, and deck openings. By choosing GNEE's NK-certified material, shipyards deliver assets that spend more time at sea and less time in dry dock undergoing corrosion-related repairs.

 

6. Stable Mechanical Properties & Consistency

Advanced rolling and heat treatment technologies ensure uniform mechanical properties across the entire plate, guaranteeing reliability in critical structural applications.

 

7. Wide Thickness & Customization Capability

Available in a wide range of thicknesses (6mm–200mm+) and dimensions, with customization options such as:

• Pre-cutting & profiling
• Shot blasting & painting
• Beveling & edge preparation

 

8. Cost-Effective Lifecycle Performance

Although high in quality, NK plates offer excellent lifecycle value by reducing repair frequency, downtime, and long-term operational costs.

 

Applications of NK Hull Structure Plate

 

NK Hull Structure Plates are essential materials in a wide range of marine and offshore engineering applications:

 

Commercial Shipbuilding

Widely used in the construction of:

• Bulk carriers
• Oil tankers
• Container ships
• General cargo vessels

 

Typical structural parts include:

• Hull structures
• Deck plates
• Side shells
• Bottom structures
• Bulkheads

 

Offshore Oil & Gas Platforms

NK high-strength plates are ideal for offshore structures that require extreme durability, such as:

• Fixed offshore platforms
• Floating production storage units (FPSO)
• Drilling rigs

They provide excellent resistance to wave impact, corrosion, and fatigue.

 

Marine Engineering & Port Infrastructure

Used in critical infrastructure projects including:

• Offshore wind power structures
• Harbors and port facilities
• Marine bridges and piers
• Subsea pipelines support structures

 

Ship Repair & Maintenance Projects

NK-certified plates are widely used in:

• Hull repair and reinforcement
• Structural upgrades
• Replacement of corroded or damaged sections

They ensure compatibility with existing ship materials and maintain classification standards.

 

Specialized Vessels

Suitable for high-performance and specialized ships such as:

• Icebreakers (requiring low-temperature toughness)
• Naval vessels
• LNG carriers
• Chemical tankers

 

Heavy Marine Equipment Manufacturing

Used in the production of:

• Shipbuilding machinery
• Marine cranes
• Deck equipment
• Structural components for offshore systems

 

Get a quote

 

Whether you are building ocean-going vessels or offshore structures, NK Hull Structure Plates from GNEE deliver the perfect balance of strength, durability, and cost-efficiency-helping you achieve safer, lighter, and longer-lasting marine projects.

 

Equivalent Grades Comparison

 

NK Grade	ASTM Equivalent	EN Equivalent	CCS Equivalent	LR Equivalent
NK A	ASTM A131 A	S235JR	CCS A	LR A
NK B	ASTM A131 B	S235JR	CCS B	LR B
NK AH36	ASTM A131 AH36	S355	CCS AH36	LR AH36
NK DH36	ASTM A131 DH36	S355	CCS DH36	LR DH36
NK EH36	ASTM A131 EH36	S355	CCS EH36	LR EH36

GNEE can provide multi-standard certification to meet different project requirements.

 

FAQ – NK Hull Structure Plate

 

What does NK certification mean?

NK certification ensures the steel meets strict marine safety and quality standards set by Nippon Kaiji Kyokai.

 

What is the difference between AH36 and DH36?

The main difference lies in impact test temperature:

• AH36: -20°C
• DH36: -40°C

 

Can GNEE provide third-party inspection?

Yes, we support third-party inspections such as SGS, BV, and TUV.

 

What thickness range can you supply?

Typically from 6mm to 200mm, customizable based on project requirements.

 

Are customized sizes available?

Yes, we offer full customization including cutting, drilling, and surface treatment.

 

What surface conditions are available?

Hot rolled, normalized, or controlled rolling conditions are available.

 

Can NK plates be used offshore?

Yes, especially high-strength grades like EH36 are widely used in offshore structures.

 

Why Choose GNEE for NK Hull Structure Plate?

 

✅ NK-certified high-quality raw materials

✅ Strong OEM & ODM capabilities

✅ Advanced production and testing equipment

✅ Rich export experience in marine steel

✅ Competitive pricing with reliable delivery

✅ One-stop solution for shipbuilding steel supply

 

Conclusion

 

NK Hull Structure Plates are essential materials for modern shipbuilding and offshore engineering, offering high strength, excellent toughness, and reliable performance in extreme marine environments. With full NK certification and global standard compliance, GNEE ensures every plate meets the highest industry requirements.

Get A Quote Now 

 

Looking for a reliable NK Hull Structure Plate supplier?

 

👉 Contact GNEE today to get:

• Competitive pricing
• Fast delivery
• Customized solutions

Send your inquiry now and let our experts support your marine project with premium NK shipbuilding steel!

 

 

 

 

 

 

 

 

We guarantee the quality and quantity of NK Hull Structure Plate. If you would like more information, please contact us!

 

Relying on many first-class equipment, such as CNC Shearing machine, Press Brake machine, Straightening machine, Roll Bending machine, Flat Bar Machine, Deburring machine etc, GNEE STEEL could provide various semi-productsand extensive forming services to customers.

 

GNEE STEEL  PROCESSING

1.CTL & SL SERVICE (141 SETS)

Currently, GNEE STEEL has imported manyadvanced CTL/SL equipment from Italy and Korea and could provide customized CTL/SL services from cold rolled stainless steel and carbon steel to hot rolled stainless steel and carbon steel as well as strips and ultra-wide sheet.

CTL FACILITIES
Max Length:16500mm

Max Width:2200mm

Max Thickness:25.4mm

Max Yield Strength:1500Mpa
SL FACILITIES

Max Width:2200mm

Max Thickness:18mm

Max slit Quantity:31

Max Yield Strength:1200Mpa

 

2.CUTTING SERVICE

GNEE STEEL imported lots of advanced cutting machines from Germany, Sweden, America and Japan, including plasmas cutting machine, water jet cutting machine, laser cutting machine, flame cutting machine and saw machine. In order to meet customers' diversified needs, GNEE STEEL also adopts nest working multi-cutting methods and intensive production to improve production capacity and save costs for the customers.

Laser Cutting Machine

Max Cutting Length:40,000mm

Max Width:4,600mm
Max Thickness:100mm

 

Flame Cutting Machine

Max Cutting Length:40,000mm

Max Width:8,000mm
Max Thickness:500mm

Plasmas Cutting Machine

Max Cutting Length:30,000mm

Max Width:5,000mm
Max Thickness:100mm

 

Water-jet Cutting

Max Cutting Length:12,000mm

Max Width:4,010mm
Max Thickness:250mm

3.FORMING SERVICE

Steel Plate Roll Bending
Maximum Rolling Thickness: up to 200mm
Maximum Width: 4200mm

   

Automatic Bending Machine-Press Brake
Max Bending Capability:3000Ton
Max Bending Length:15,000mm

Expert in Bending High-Strength & Wear-Resistant Steels

  

  

Punching Machine

Max Width:3,070mm
Max Thickness:8mm

Max Pressure:250t

BEVELING SERVICE

GNEE STEEL beveling platform has edge milling machine, edge planer, flame / plasma groove cutting machine, flame groove cutting robot, desktop chamfering machine, gantry planerand other advanced equipment to provide customers with parts prefabrication services,daily processing of V-type, Y-type, X-type and U-type grooves, and guarantee subsequent processes such as welding and assembly of products.

 

Milling：
Max Cutting Length:18,000mm

Max Width:4500mm
Max Thickness:120mm

 

  

Beveling:
Max Length:16,000mm

Max Thickness:80mm

MACHINING SERVICE

GNEE STEEL owns CNC Portal-type Boring and Milling machine,CNC Floor-type Boring and Milling machine, Vertical Precision 5-axis Milling Machine, Portal-type Planer, Vertical Lathe, Cylindical Grinding machine, Hydraulic Planer and CNC Lathe and could provide fine machining of large spare parts and structural parts for customers.

Gantry Type Boring & Milling Maching Center

Max Length:48000mm

Max Width:12500mm
Max Height:8000mm

Max Diameter:10500mm

Deep-hole Drilling Equipment
Max Driling Depth:1,100mm
Max Bore Diameter:φ80mm
Max Diametar:φ4,500mm

MMulti-hole Drilling Equipment

Max Length:13,000mm
Max Width:10,000mm
Max Bore Diameter:φ105mm
Max Drilling Depth:250mm

Floor Boring And Milling Machine
Max Length:24,000mm
Max Height:8,000mm
Turntable Dimensions:9x5m

Vertical Lathe

Max Height:6,000mm

Max Diametar:φ22,00mm

Automated Edge Milling Machine

The Automated Edge Milling Machine is a leading product in heavy-duty milling equipment. It is primarily used for weld groove preparation (beveling) on large-format plates made of stainless steel, carbon steel, and special steel grades. It can process plates with a maximum thickness of up to 90mm, a length of 16 meters, and a width of 4 meters.

 

It is equipped with dual milling units and a fully automatic milling cutter head changing system, enabling automated 4-edge beveling. Its standout feature is the profiling technology used when milling wavy plates and irregularly shaped products, which ensures absolute consistency of the groove after milling.

 

Utilizing specially designed milling cutter heads, it can execute highly difficult and complex groove profiles in a single pass.

 

Materials: Plain carbon steel, pressure vessel steel, wear-resistant steel, high-strength steel, stainless steel, nickel-based alloys, etc.
Width: 1200 - 4200 mm
Length: 5800 - 16000 mm
Thickness: 5 - 90 mm
Weight: Up to 35 tons

 

This edge milling machine is the world's premier automated bevel milling equipment. With its excellent structural design and advanced data algorithms, it achieves full automation from plate detection to the actual milling process, significantly improving processing efficiency while guaranteeing high precision.

 

• Processing Accuracy

Length accuracy: ±1mm when L < 10m; ±2mm when L > 10m;

Width accuracy: ±1mm;

Diagonal accuracy: ±2mm;

Root face accuracy (blunt edge): ±1mm for Y-grooves; +0.5mm for X-grooves.

• Processing Efficiency

The processing efficiency is more than 10 times that of conventional edge milling or edge planing equipment.

HEAT TREATMENT

Heat Treatment Furnace
Max Furnace Size:36x12x13.5m
Max Rated Temperature:1100℃
Max Loading Capacity:800t

Heat Treatment of Pressure Vessels
Heat Treatment of Mining Equipment
Heat Treatment of Tube Sheet
Heat Treatment of Pressure Vessel Head

 

 

GNEE STEEL is currently participating in the procurement phase of a 100,000m³ full containment ammonia storage tank project, supplying high-quality steel plates for critical tank components. Due to the corrosive nature of ammonia and the risk of Ammonia Stress Corrosion Cracking (SCC), the project requires strict metallurgical control of materials according to EN 10028-3 standards.

 

One of the most important technical requirements of this project is the strict limitation of the actual Yield Strength (Re) for all NL2 grade materials. To prevent SCC risks in ammonia storage environments, the actual yield strength must not exceed 390 MPa, regardless of the nominal values specified in the standard or plate thickness ranges. This requirement places higher demands on steelmaking process control, heat treatment stability, and material testing.

 

Raw high-strength steel plates ready for the 100,000 m³ full containment ammonia storage tank production

 

Project Materials and Technical Requirements

 

The project mainly uses P355NL2 and P275NL2 normalized pressure vessel steel plates, which are widely applied in low-temperature storage tanks due to their excellent toughness and weldability.

 

Key technical specifications include:

• Material grades: P355NL2 and P275NL2 (Normalized)
• Yield strength: Standard minimum / Maximum limited to 390 MPa
• Hardness: ≤ 225 HBW in base material
• Impact testing: Charpy-V notch test at -50°C, minimum 27J
• Certification: EN 10204 3.1 certificate, with optional 3.2 certification

 

These strict requirements ensure that the steel plates maintain stable mechanical properties and high resistance to ammonia-induced stress corrosion during long-term operation.

 

Precision rolling and forming of steel plates into curved sections for the 100,000 m³ ammonia storage tank.

 

Project Plate Quantities and Thickness Distribution

 

The total steel demand for this ammonia storage tank project is several thousand tons, mainly distributed across different tank sections:

 

P355NL2 – Inner & Outer Tank Shell Plates

• Lower shell courses: 50 mm thickness – approx. 2,000 tons
• Middle shell courses: 25 mm thickness – approx. 1,400 tons
• Upper shell courses: 10 mm thickness – approx. 500 tons

 

P275NL2 – Tank Bottom Plates

• Thickness: 10–15 mm – approx. 750 tons

 

P275NL2 – Suspended Roof Structure

• Thickness: 5–8 mm – approx. 180 tons

 

S275JR – Outer Roof (Ambient Structure)

• Thickness: 10 mm – approx. 450 tons

 

To improve tank fabrication efficiency and reduce circumferential welds, the project also requires wide steel plates to minimize welding joints, which helps reduce the potential risk of SCC in ammonia service conditions.

 

Formed steel segments wrapped and racked for protection, ready for 100,000 m³ ammonia storage tank assembly.

 

GNEE STEEL provides high-precision steel plate rolling and cylinder fabrication solutions for tank manufacturers worldwide. Send us your plate specifications or fabrication drawings for a fast quotation.

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TYPE	GRADE	SPECIFICATIONS
Carbon Steel / Low Alloy Coil	Q235A/B/C/D/Q355B(Q345B)/C/D/E/SS400/SAPH400-C/ASTMA283Grade C	0.7~2.0*1250/1500mm*C 2.3~19.5*1250/1500/1800/2000mm*C
Medium Heavy Plate	Q235B/Q355B(Q345B)/C/D/E	6.0-200x150mm-4000mmxL
Vessel Plate	Q245R/Q345R/HP295/SA516MGR485/SA516GR70/P355NL2/P275NL2/ S275JR//SPV490/ASTM A537 Class 1/Class 2	2.5-120x1500mm-3000mmxL
High Strength Steel	510L/610L/700L/750L/BS600MCK4/BS700MCK2/BS700MCK4/ BS960E/BWELDY700QL2/L4/BWELDY960QL4/HG60D/70D/785D/ Q460D/Q550D/690D/690E/TQ600MCD/TQ700MCD/S700MCD/ WYS600/700/STRENX700MCE/Q490E/Q490D	1.2-60x 1500mm-2500mmxL
Patterned Steel	HQ235A|B	1.2-60x 1500mm-2500mmxL
Wear-resistance Steel	NM360/400/450/500/NM300TP/400TP/450TP/ ABREX400/450/500/B-HARD450XKY/ CREUSABRO4800/8000/EH C400LE/450LE/500LE/ HADOX450/500	3.0-50x1250mm-3300mmxL
Cold Rolled Coil	DC01/RECC/REDT/SPCC/ST12	0.5-3.0x1250mm-1500mmxC
Galvanized Plate	DC51D+AZ/DC51D+Z/DX51D+Z/SGH340+Z275/Z275/Z120/S350GD+ZM275	0.45-3.0x1250mm-1500mmxC
Pickled Coil	DD11/SPHC	2.0-6.0x1500xC

Stainless Steel Material and Surface Specifications

TYPE	GRADE	THICKNESS	SURFACE
Austenitic	304/304H/304L/304J1	0.25-150mm	2B/BA/NO.4/8K/SB/HL/NO.1
Austenitic	321	0.4-80mm	2B/BA/NO.4/8K/SB/HL/NO.1
Austenitic	316/316L/317L/316Ti	0.3-80mm	2B/BA/NO.4/8K/SB/HL/NO.1
Austenitic	201(J1/J2/J5)	0.35-12mm	2B/NO.1/1D
Ferrite	430	0.4-3.0mm	2B/BA/NO.4/8K/SB/HL
Ultra Pure Ferrite	443	0.4-2.0mm	2B
Ultra Pure Ferrite	436L/439/444/441	0.5-3.0mm	2B/2D

Special Steel / Nickel Base Alloy

TYPE	GRADE	GRADE (ASTM)	GRADE (EN)	THICKNESS
Heat-resistant Steel	309S	S30908	1.4833	0.5-40mm
Heat-resistant Steel	310S	S31008	1.4845	0.5-40mm
Duplex Stainless Steel	2101	S32101	1.4162	1.5-50mm
Duplex Stainless Steel	2304	S32304	1.4362	3.0-50mm
Duplex Stainless Steel	2205	S32205/S31803	1.4462	0.5-60mm
Duplex Stainless Steel	2507	S32750	1.4410	1.0-60mm
Super Austenitic-Steel	904L	N08904	1.4539	0.6-50mm
Super Austenitic-Steel	254SMO	S31254	1.4547	0.5-50mm
Super Austenitic-Steel	1.4529	N08926	1.4529	0.5-50mm
Super Austenitic-Steel	AL-6XN	N08367	1.4478	0.5-50mm
Nickel Base Alloy	Alloy 31	N08031	1.4562	1.0-50mm
Nickel Base Alloy	800	N08800	1.4876	0.8-50mm
Nickel Base Alloy	800H	N08810	1.4958	0.8-50mm
Nickel Base Alloy	800HT	N08811	1.4959	0.8-50mm
Nickel Base Alloy	Alloy 28	N08028	1.4563	1.0-20mm
Nickel Base Alloy	Alloy 20	N08020	2.4660	1.0-20mm
Nickel Base Alloy	825	N08825	2.4858	0.8-40mm
Nickel Base Alloy	C276	N10276	2.4819	0.5-50mm
Nickel Base Alloy	C22	N06022	2.4602	1.0-50mm
Nickel Base Alloy	625	N06625	2.4856	0.8-20mm
Nickel Base Alloy	400	N04400	2.4360	1.0-20mm
Nickel Base Alloy	600	N06600	2.4816	1.0-50mm
Nickel Base Alloy	Pure Ni 201	N02201	2.4061	0.5-20mm
Titanium	TA1	Gr.1	Class 1	0.5-50mm
Titanium	TA2	Gr.2	Class 2	0.5-50mm

 

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