What is the delivery condition of P275NH?

P275NH is a non-alloy pressure vessel steel specified in EN 10028-2 standard. It belongs to the weldable fine-grain structural steel category, mainly used for manufacturing pressure-bearing equipment operating at moderate temperatures.

P275NH Processing Characteristics 

Normalization-Driven Performance Optimization：Normalization is a mandatory core process, involving heating to 890-950℃, sufficient heat preservation, and air cooling. This treatment refines the grain structure, effectively improving toughness and ensuring stable mechanical properties, which lays a foundation for its high-temperature and pressure-resistant service.

Excellent Formability：It exhibits good cold and hot forming performance. Cold forming can be completed at room temperature with low forming force, suitable for simple shapes like bending and stamping. Hot forming (700-1050℃) adapts to complex components, with optional post-forming stress relief to avoid residual stress.

Superior Weldability：Welding is easy without obvious cracks. Recommended processes include SMAW, GMAW, and GTAW. Preheating (80-150℃, based on thickness) and post-weld heat treatment (550-650℃) can optimize joint performance, ensuring no significant strength loss after welding.

Rigorous Post-Processing Inspection：Post-processing mainly includes grinding to remove burrs and defects. Strict ultrasonic inspection is required per EN 10028-3 to eliminate internal flaws, ensuring product consistency and reliability for critical industrial applications.

Main Applications

Boiler and Pressure Vessel Manufacturing：Core application field, used to produce boiler drums, steam headers, heat exchangers, high-pressure storage tanks, and reactor shells. It is the preferred material for equipment bearing high temperature and pressure in thermal power, chemical, and metallurgical industries.

Petrochemical Industry：Applied in oil refining, natural gas processing, and chemical synthesis equipment, including separators, desulfurization towers, pipeline fittings (flanges, valves), and medium storage tanks for crude oil, natural gas, and chemical reagents.

Power Generation Industry：Widely used in thermal power plants (high-pressure water supply pipes, turbine casings, economizers) and hydropower stations (pressure pipelines, surge tanks), as well as auxiliary equipment for nuclear power plants (non-core pressure-bearing components).

Other Fields：Used in marine engineering (pressure cabins, shipborne storage tanks), food processing (high-temperature sterilization pots), and bridge/building structures (load-bearing components requiring high strength and toughness).

Corresponding Application Conditions

Temperature Conditions：Suitable for long-term operation at -20℃ to 400℃. It maintains stable mechanical properties without deformation or failure under continuous high-temperature conditions, and resists low-temperature impact at -20℃, meeting cold and high-temperature working environment requirements.

Pressure Conditions：Adaptable to medium and high-pressure working environments, with a maximum allowable working pressure matching its yield strength (≥275MPa) and tensile strength (390-510MPa), suitable for equipment under combined pressure and thermal loads.

Medium Conditions：Resistant to mild corrosion from neutral and weakly corrosive media (water, steam, crude oil, natural gas). Not suitable for strong acid/alkali environments unless additional anti-corrosion treatment is applied.

Processing and Installation Conditions：Requires standardized forming, welding, and heat treatment processes (preheating 80-150℃, post-weld heat treatment 550-650℃). Must pass ultrasonic inspection to ensure no internal defects before application, ensuring safe operation of key equipment.

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What are the inspection methods for P275NH after manufacturing?

Common inspections: visual inspection (surface defects), ultrasonic testing (internal flaws), radiographic testing (weld quality), tensile testing, impact testing, and hardness testing, complying with EN 10028-2 and customer specifications.

What is the difference between P275NH and P275NL2?

The key difference is impact test temperature: P275NH (-20°C) vs. P275NL2 (-50°C). P275NL2 has better low-temperature toughness, suitable for colder environments, while P275NH is for moderate low-temperature conditions.

Is P275NH suitable for boiler drum manufacturing?

Yes, P275NH is widely used for boiler drums operating at moderate temperatures and pressures. Its good weldability, strength, and toughness meet the strict safety requirements of boiler drum manufacturing standards.

What is the maximum carbon equivalent (CEV) of P275NH?

The maximum carbon equivalent (CEV) of P275NH is 0.42%, calculated by CEV = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15. A low CEV ensures excellent weldability and avoids cold cracking during welding.

Can P275NH be machined easily?

Yes, P275NH has good machinability due to its moderate hardness and fine-grain structure. Ordinary cutting tools can be used, with proper cutting speed and feed rate to achieve high machining accuracy and surface quality.

What is the weight per square meter of a P275NH plate with 10mm thickness?

The density of P275NH is 7.85 g/cm³. A 10mm thick plate weighs 78.5 kg per square meter (calculation: 10mm × 7.85 g/cm³ × 100cm × 100cm / 1000 = 78.5 kg).

What are the storage requirements for P275NH plates?

Store P275NH plates in a dry, well-ventilated warehouse, away from moisture and corrosive substances. Stack them on wooden supports to prevent contact with the ground, and cover with waterproof cloth to avoid rusting.

Can P275NH be used in high-pressure applications?

It is suitable for moderate-pressure applications (usually ≤10 MPa, depending on temperature and thickness). For high-pressure conditions, high-strength pressure vessel steels with higher yield strength (e.g., P355NH) are recommended.

What is the thermal conductivity of P275NH?

The thermal conductivity of P275NH is about 45 W/(m·K) at room temperature. This good thermal conductivity makes it suitable for heat exchanger and boiler applications where heat transfer efficiency is important.

What certificates are required for P275NH supply?

Supply certificates for P275NH include EN 10204 3.1 or 3.2 certificates, which confirm compliance with standard requirements. They include chemical composition, mechanical properties, heat treatment, and inspection results.