What is EN 10028-3 Grade P275NL2 Pressure Vessel Steel Plate

EN 10028-3 Grade P275NL2 is a pressure vessel steel specified under the EN 10028 standard, which supersedes older BS and DIN standards.

P275NL2 belongs to the group of non-alloy and alloy steels with specified elevated temperature properties, primarily intended for boilers, pressure vessels, and pipelines transporting hot liquids.

Compared with NL1 grades, P275NL2 provides enhanced low-temperature impact toughness, making it suitable for especially low-temperature service environments.

Steel Standard: EN 10028-3

Steel Grade: P275NL2

Steel Category: Steel for Boilers and Pressure Vessels

Available Dimensions

Thickness: 6 mm – 300 mm

Width: 1500 mm – 4050 mm

Length: 3000 mm – 15000 mm

P275NL2 steel is specifically designed for pressure equipment operating under low and especially low temperature conditions.
Thanks to its excellent low-temperature impact toughness, stable mechanical properties, and good weldability, P275NL2 steel plates are widely applied in the following fields:

Boilers

P275NL2 is commonly used in the manufacture of industrial and utility boilers, including boiler shells, drums, and pressure-bearing components.
Its stable yield strength and enhanced impact toughness make it suitable for low-temperature start-up and shutdown conditions, reducing the risk of brittle fracture.

Pressure Vessels

This grade is extensively applied in pressure vessels for gases and liquids, such as storage vessels, separators, and reactors.
P275NL2 meets stringent low-temperature Charpy impact requirements, ensuring structural integrity when vessels operate in cold climates or under fluctuating temperature conditions.

Pressure Pipes for Hot Liquids

P275NL2 steel plates are used for producing pressure pipes and pipelines that transport hot liquids under pressure.
The material offers a reliable balance between strength and ductility, enabling safe operation under thermal stress and internal pressure.

Petrochemical and Chemical Equipment

In petrochemical and chemical plants, P275NL2 is widely used for columns, towers, heat exchangers, and reactors.
Its resistance to brittle fracture and good weldability support complex fabrication processes and long-term service reliability in aggressive operating environments.

Energy and Power Plant Components

P275NL2 steel plates are commonly selected for power generation equipment, including pressure parts in thermal and energy facilities.
The grade performs well in environments involving low ambient temperatures, pressure loads, and temperature variations, making it suitable for energy infrastructure in cold regions.

P275NL2 steel plates can be supplied with the following additional tests and specifications upon request:

HIC Test

NACE MR0175 / ISO 15156

Z-direction testing: Z15 / Z25 / Z35

EN supplementary requirements: S1, S2, S3, S4.1, S5, S6, S7, S8, S9, S11, S12, S14, S17

(% by mass, max unless otherwise stated)

Carbon Equivalent (Ceq):
Ceq = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15 (%)

Delivery condition: Normalized (N)

(Exact equivalency may vary depending on application and specification.)

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Q1: What is EN 10028-3 P275NL1 steel plate?

A:
P275NL1 is a weldable fine-grain steel specified in EN 10028-3, intended for pressure vessels and boilers operating under low-temperature conditions. The material is supplied in the normalized (N) condition and is designed to provide reliable strength, toughness, and weldability.

Q2: What does the designation "P275NL1" mean?

A:

P – Steel for pressure purposes

275 – Minimum yield strength of 275 MPa (for thinner plates)

N – Normalized or normalized rolled delivery condition

L1 – Guaranteed low-temperature impact toughness level

Q3: What are the key mechanical properties of P275NL1?

A:
Typical mechanical requirements (depending on thickness) include:

Yield strength: ≥ 275 MPa

Tensile strength: approx. 390–510 MPa

Elongation: ≥ 23–24%

Charpy V-notch impact test: Guaranteed at low temperature (typically −40 °C, per standard requirements)

Exact values vary by plate thickness and must be verified against EN 10028-3 and the mill test certificate.

Q4: What are the main chemical composition requirements?

A:
P275NL1 has controlled chemical composition to ensure weldability and low-temperature toughness:

Carbon (C): Low carbon content to improve weldability

Manganese (Mn): Enhances strength and toughness

Silicon (Si): Used as a deoxidizer

Phosphorus (P) & Sulfur (S): Strictly limited to reduce brittleness

Micro-alloying elements (Nb, V, Ti): Used for grain refinement and improved impact performance

Q5: Is P275NL1 suitable for low-temperature service?

A:
Yes. P275NL1 is classified as a low-temperature quality steel, with mandatory impact testing at sub-zero temperatures. It is commonly used in pressure vessels and equipment exposed to cold climates or low operating temperatures.

Q6: What is the difference between P275NL1 and P275NH?

A:

P275NL1: Optimized for low-temperature toughness

P275NH: Optimized for elevated-temperature service

Selection depends on the design temperature of the pressure equipment.

Q7: How is P275NL1 supplied?

A:
The steel is supplied in the normalized (N) condition, ensuring a fine-grain microstructure and consistent mechanical properties across the plate thickness.