EN10028 P275NL1 steel plate/sheet for boilers and Pressure Vessels steels

Under the EN 10028 standard, P275NL1 steel plate and sheet are classified as pressure vessel steels for boilers and pressure equipment.

EN 10028 P275NL1 is a normalized fine-grain steel specifically designed for service at low temperatures, and it is widely used in the fabrication of pressure vessels, boilers, and pipelines carrying hot liquids.

Thanks to its stable mechanical performance, good weldability, and reliable low-temperature toughness, P275NL1 is a commonly selected material in the energy, petrochemical, and process industries.

Note:
¹ Values depend on specific thickness and delivery conditions as defined in EN 10028-3.

Impact Test Requirements of EN 10028 P275NL1 Steel

Delivery condition: Normalized (N)

Due to its excellent performance under pressure and low-temperature conditions, EN 10028 P275NL1 steel plate is commonly applied in:

Low-temperature pressure vessels

Boilers and steam equipment

Heat exchangers

Storage tanks for gases and liquids

Petrochemical and chemical processing equipment

Power plant pressure systems

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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.