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P245NB Steel Sheet and Strip for Welded Gas Cylinders

Q: What is the main difference between LR Grade AH32 and LR Grade AH36 shipbuilding steel plates?

Both are high-strength hull structural steels certified by Lloyd’s Register (LR). The key difference lies in their yield strength grades: LR AH32 has a minimum yield strength of 315 MPa, while LR AH36 has a minimum yield strength of 355 MPa.Therefore, LR AH32 is suitable for conventional-tonnage vessels and general offshore engineering projects, offering better cost-effectiveness; LR AH36, on the other hand, is intended for applications requiring higher strength, such as ultra-large vessels and high-load-bearing offshore structures.

Q: Does your LR Grade AH32 shipbuilding steel plate support third-party inspection?

Yes. All of our LR Grade AH32 shipbuilding steel plates support inspections by internationally recognized third-party organizations such as SGS, BV, and DNV. They come with complete official LR certification and original mill test certificates, ensuring full quality traceability.

Q: What processing services can you provide for LR Grade AH32 shipbuilding steel plates?

We offer one-stop value-added processing services, including precision cutting, bending, drilling, beveling, surface derusting, shot blasting, anti-corrosion treatment, and heat treatment, to meet all custom manufacturing and installation requirements for offshore engineering projects.

Q: Does LR Grade AH32 shipbuilding steel plate require special welding procedures?

LR Grade AH32 shipbuilding steel plate offers excellent overall weldability, stable material properties, and a low carbon equivalent. It is suitable for all conventional shipbuilding welding processes and does not require complex preheating or special protective measures.Standard marine welding operating procedures ensure consistent weld quality, effectively reduce construction difficulties, and improve project efficiency.

Q: What is the application of LR Grade AH32 shipbuilding steel plate?

LR Grade AH32 shipbuilding steel plate is primarily used in the construction of commercial vessels, conventional offshore platforms, coastal marine infrastructure, and the maintenance of marine equipment. It is suitable for various marine engineering applications that require high strength and stable overall structural performance.

Q: What is the weldability of LR Grade E shipbuilding steel plates?

The weldability is good, and the carbon equivalent (CEV) is typically controlled at ≤ 0.40% (depending on the specific thickness).For thicknesses of 40 mm or less, preheating is generally not required at ambient temperatures (≥0°C), but low-hydrogen electrodes must be used.For plates thicker than 40 mm or highly constrained joints, preheating to 50°C–100°C is recommended to reduce the cooling rate and prevent cold cracks.Important Note: Welding consumables approved by the classification society and compatible with LR Grade E must be used.

Q: What is the main difference between LR Grade D and Grade E marine steel?

The basic strength parameters of the two grades are the same; the key difference lies in low-temperature impact resistance and application scenarios.LR Grade D must pass an impact test at -20°C and is suitable for conventional cold-water regions; LR Grade E must pass an impact test at -40°C and offers superior low-temperature toughness and resistance to brittle fracture, making it suitable for polar and extremely cold marine environments.

Q: What is the application of LR Grade E shipbuilding steel plates?

LR Grade E shipbuilding steel plate is a high-performance, ordinary-strength marine structural steel plate with exceptional impact toughness at ultra-low temperatures of -40°C. It is primarily used in polar icebreakers, polar research vessels, ultra-cold ocean-going vessels, extremely cold offshore structures, and high-end marine infrastructure requiring resistance to brittleness at extremely low temperatures. It serves as an upgraded replacement for LR Grade D shipbuilding steel plate in polar and extremely cold marine environments.

Q: What are the delivery conditions for LR Grade D shipbuilding steel plates?

The standard delivery conditions for LR Grade D shipbuilding steel plates are as follows:1) Hot-rolled (HR): Suitable for thin plates with a thickness of ≤12 mm; this is the standard supply condition.2) Thermomechanically Controlled Process (TMCP): The primary delivery condition for medium- and thick plates; grain refinement ensures compliance with impact toughness requirements at -20°C without the need for additional heat treatment.3) Normalized (N): Suitable for thick plates with a thickness of ≥50 mm; used for critical components with stringent low-temperature toughness requirements.All delivery conditions must pass LR third-party inspection prior to shipment.

Q: What processing services do you offer for LR Grade D marine steel plates?

We provide one-stop value-added processing services, including precision cutting, bending, drilling, beveling, surface derusting, shot blasting, anti-corrosion treatment, and heat treatment, to meet all custom manufacturing and installation requirements for extreme-low-temperature offshore engineering projects.

P245NB Steel Sheet and Strip for Welded Gas Cylinders

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EN 10120 P245NB steel plates and strips exhibit good weldability, toughness, and cold formability, making them suitable for the manufacturing of medium and low-pressure welded gas cylinders under conventional service conditions.

Standard :
EN 10120
Grade :
P245NB
Thickness :
2.0 - 14.0 mm
Width :
1100.0 - 1500 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

EN 10120 P245NB is an economical, highly weldable steel specifically designed for medium to low-pressure gas cylinders. Its core advantages include low carbon content for easy welding and stable toughness, making it suitable for manufacturing welded gas cylinders under conventional working conditions. When selecting this steel, it is essential to focus on the mechanical properties corresponding to thickness, operating temperature (matching quality grade), and medium compatibility.

Grade	P245NB
Standard	EN 10120: European Standard - Steel sheet and strip for welded gas cylinders
Delivery Conditions	Normalized
Surface Quality	Free from surface defects such as cracks, inclusions, delaminations, etc.
Weldability	Good weldability, control the heat input.
Machinability	Excellent cold working plasticity
Quality Control	Material certificate Non-destructive testing (such as UT) can be added as required.

Chemical Composition

Grade	P245NB
Element	C	Si	Mn	P	S	Al (Total)	N	Nb	Ti
Content (%)	≤ 0.16	≤ 0.25	≥ 0.30	≤ 0.025	≤ 0.015	≥ 0.020	≤ 0.009	≤ 0.050	≤ 0.030

Carbon Equivalent of P310NB Steel Sheet and Strip for Welded Gas Cylinders: CEV ≤ 0.4% (Thickness ≤ 16 mm)

Carbon equivalent (CEV) is calculated using the International Institute of Welding (IIW) formula:

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

Mechanical Properties

Grade	Yield Strength (ReH) [min, MPa]	Tensile Strength (Rm) [MPa]	Elongation (A) [min, %]	Impact Energy (KV) [min]
P245NB	245	360 - 450	26 (t < 3 mm) 34 (3 ≤ t ≤ 5 mm)	27J (at 0°C)

Applications

The primary use of P245NB steel plates and strips is for manufacturing various refillable welded steel gas cylinders, suitable for non-corrosive or mildly corrosive gases. Common applications include:

1. Industrial gas cylinders: such as oxygen, nitrogen, argon, carbon dioxide, etc.

2. Medical gas cylinders: such as medical oxygen, nitrous oxide, etc.

3. Fire extinguisher cylinders.

4. Other medium to low-pressure welded pressure vessels.

Other Information

Usage Precautions

1. Medium Restrictions: Suitable only for non-corrosive or weakly corrosive gases (such as air, nitrogen, liquefied gas, natural gas, etc.). Use with highly corrosive media like strong acids, strong alkalis, or halogens is strictly prohibited (stainless steel or corrosion-resistant alloys must be used instead).

2. Thickness and Strength Matching: When the steel thickness exceeds 16mm, the yield strength will gradually decrease as required by standards. The wall thickness must be adjusted according to the cylinder's design pressure.

3. Low-Temperature Conditions: The impact energy test temperature for Grade B steel is 0°C. If used in low-temperature environments below -20°C, an upgrade to Grade C (-20°C impact) or Grade D (-40°C impact) is necessary to avoid the risk of brittle fracture.

International Equivalent Materials

Grade	Standard	Yield Strength (ReH) [min, MPa]	Tensile Strength (Rm) [MPa]	Elongation (A) [min, %]
P245NB	EN 10120	245	360 - 450	26 (t < 3 mm) 34 (3 ≤ t ≤ 5 mm)
HP265	GB/T 6653	265	410 - 520	21 (t < 3 mm) 27 (3 ≤ t ≤ 5 mm)

* Equivalent materials are only approximations, mechanical properties and chemical composition must be compared during application design.

FAQ

Q1:

What is the main difference between LR Grade AH32 and LR Grade AH36 shipbuilding steel plates?

Both are high-strength hull structural steels certified by Lloyd’s Register (LR). The key difference lies in their yield strength grades: LR AH32 has a minimum yield strength of 315 MPa, while LR AH36 has a minimum yield strength of 355 MPa.

Therefore, LR AH32 is suitable for conventional-tonnage vessels and general offshore engineering projects, offering better cost-effectiveness; LR AH36, on the other hand, is intended for applications requiring higher strength, such as ultra-large vessels and high-load-bearing offshore structures.

Q2:

Does your LR Grade AH32 shipbuilding steel plate support third-party inspection?

Yes. All of our LR Grade AH32 shipbuilding steel plates support inspections by internationally recognized third-party organizations such as SGS, BV, and DNV. They come with complete official LR certification and original mill test certificates, ensuring full quality traceability.

Q3:

What processing services can you provide for LR Grade AH32 shipbuilding steel plates?

We offer one-stop value-added processing services, including precision cutting, bending, drilling, beveling, surface derusting, shot blasting, anti-corrosion treatment, and heat treatment, to meet all custom manufacturing and installation requirements for offshore engineering projects.

Q4:

Does LR Grade AH32 shipbuilding steel plate require special welding procedures?

LR Grade AH32 shipbuilding steel plate offers excellent overall weldability, stable material properties, and a low carbon equivalent. It is suitable for all conventional shipbuilding welding processes and does not require complex preheating or special protective measures.

Standard marine welding operating procedures ensure consistent weld quality, effectively reduce construction difficulties, and improve project efficiency.

Q5:

What is the application of LR Grade AH32 shipbuilding steel plate?

LR Grade AH32 shipbuilding steel plate is primarily used in the construction of commercial vessels, conventional offshore platforms, coastal marine infrastructure, and the maintenance of marine equipment. It is suitable for various marine engineering applications that require high strength and stable overall structural performance.

Q6:

What is the weldability of LR Grade E shipbuilding steel plates?

The weldability is good, and the carbon equivalent (CEV) is typically controlled at ≤ 0.40% (depending on the specific thickness).

For thicknesses of 40 mm or less, preheating is generally not required at ambient temperatures (≥0°C), but low-hydrogen electrodes must be used.

For plates thicker than 40 mm or highly constrained joints, preheating to 50°C–100°C is recommended to reduce the cooling rate and prevent cold cracks.

Important Note: Welding consumables approved by the classification society and compatible with LR Grade E must be used.

Q7:

What is the main difference between LR Grade D and Grade E marine steel?

The basic strength parameters of the two grades are the same; the key difference lies in low-temperature impact resistance and application scenarios.

LR Grade D must pass an impact test at -20°C and is suitable for conventional cold-water regions; LR Grade E must pass an impact test at -40°C and offers superior low-temperature toughness and resistance to brittle fracture, making it suitable for polar and extremely cold marine environments.

Q8:

What is the application of LR Grade E shipbuilding steel plates?

LR Grade E shipbuilding steel plate is a high-performance, ordinary-strength marine structural steel plate with exceptional impact toughness at ultra-low temperatures of -40°C. It is primarily used in polar icebreakers, polar research vessels, ultra-cold ocean-going vessels, extremely cold offshore structures, and high-end marine infrastructure requiring resistance to brittleness at extremely low temperatures. It serves as an upgraded replacement for LR Grade D shipbuilding steel plate in polar and extremely cold marine environments.

Q9:

What are the delivery conditions for LR Grade D shipbuilding steel plates?

The standard delivery conditions for LR Grade D shipbuilding steel plates are as follows:

1) Hot-rolled (HR): Suitable for thin plates with a thickness of ≤12 mm; this is the standard supply condition.

2) Thermomechanically Controlled Process (TMCP): The primary delivery condition for medium- and thick plates; grain refinement ensures compliance with impact toughness requirements at -20°C without the need for additional heat treatment.

3) Normalized (N): Suitable for thick plates with a thickness of ≥50 mm; used for critical components with stringent low-temperature toughness requirements.

All delivery conditions must pass LR third-party inspection prior to shipment.

Q10:

What processing services do you offer for LR Grade D marine steel plates?

We provide one-stop value-added processing services, including precision cutting, bending, drilling, beveling, surface derusting, shot blasting, anti-corrosion treatment, and heat treatment, to meet all custom manufacturing and installation requirements for extreme-low-temperature offshore engineering projects.

Q11:

Does your LR Grade D shipbuilding steel plate support third-party inspection?

Yes. All of our LR Grade D shipbuilding steel plates are fully compatible with inspections by internationally recognized third-party organizations such as SGS, BV, and DNV. They come with complete official LR certification and original factory test reports, ensuring comprehensive quality traceability.

Q12:

What is the difference between LR Grade B and Grade D marine steel?

The key difference lies in low-temperature impact resistance. LR Grade B is tested at 0°C and is suitable for temperate and mildly cold waters; LR Grade D is subject to a mandatory -20°C low-temperature impact test, offering greater cold resistance and making it suitable for cold waters and extremely cold marine environments. Both grades have the same basic tensile strength and yield strength.

Q13:

Do you provide official certification for your LR Grade D marine steel plates?

Yes. All of our LR Grade D shipbuilding steel plates hold valid official certification from Lloyd’s Register (LR) and EN 10204 3.2 mill test certificates. These certificates are internationally recognized and fully support global project bidding, high-standard engineering acceptance, and cross-border customs clearance requirements.

Q14:

What is the range of available dimensions for your LR Grade B marine steel plates?

Thickness: 5 mm - 150 mm (thicknesses ≥ 40 mm: require normalizing or TMCP heat treatment)

Width: 1,500 mm - 4,000 mm

Length: 6,000 mm - 18,000 mm

We offer custom flame-cutting or plasma-cutting services based on shipyard drawings, with cutting tolerances meeting LR rules requirements.

Q15:

Does your LR Grade B shipbuilding steel plate support third-party inspection?

Yes. All of our LR Grade B shipbuilding steel plates are subject to inspection by internationally recognized third-party organizations such as SGS, BV, and DNV, and come with complete official LR certification and original Mill Test Certificate (MTC) to ensure full quality traceability.