P265GH Carbon Steel: Pressure Vessel Steels (EN 10028-2)
P265GH carbon steel, designated under EN 10028-2 for flat products in pressure vessel applications, is a non-alloy quality steel widely used for welded structures requiring moderate strength and good weldability. With its controlled chemical composition, it offers reliable performance in moderate-temperature environments, making it ideal for boilers, pressure vessels, and piping systems. This article explores its chemical makeup, mechanical properties, manufacturing processes, applications, and comparative advantages.
1. Core Chemical Composition (EN 10028-2 Standard)
| Element | Content Range | Function |
|---|---|---|
| Carbon (C) | 0.08 – 0.20% | Provides basic strength and hardenability; controlled to ensure weldability |
| Manganese (Mn) | 0.80 – 1.40% | Improves strength, toughness, and deoxidation; enhances hot workability |
| Silicon (Si) | ≤ 0.40% | Aids in deoxidation and improves high-temperature scaling resistance |
| Phosphorus (P) | ≤ 0.025% | Limited impurity; excess reduces ductility and increases brittleness |
| Sulfur (S) | ≤ 0.015% | Controlled to minimize hot shortness and ensure good weldability |
| Chromium (Cr) | ≤ 0.30% | Trace element; slight enhancement of corrosion resistance |
| Molybdenum (Mo) | ≤ 0.08% | Improves creep strength at elevated temperatures |
2. Key Mechanical Properties (Room Temperature)
- Tensile Strength (Rm): 410 – 530 MPa (EN 10028-2 normalized condition)
- Yield Strength (ReH): ≥ 265 MPa (minimum for thicknesses up to 16 mm; ensures pressure containment)
- Elongation (A): ≥ 22% (good ductility for forming and fabrication)
- Impact Toughness (KV): ≥ 27 J at 20°C (longitudinal; suitable for moderate impact loads)
- Hardness (HB): ≤ 170 (Brinell; facilitates machining and welding)
3. Manufacturing Process Characteristics
- Steelmaking: Basic oxygen furnace (BOF) or electric arc furnace (EAF) followed by ladle refining to achieve low impurity levels and consistent composition.
- Hot Rolling: Rolled at 900-1100°C into plates or sheets, with controlled cooling to normalize the microstructure and prevent excessive grain growth.
- Heat Treatment: Normalizing at 880-950°C for 1 hour per 25 mm thickness, followed by air cooling to refine grain structure and improve toughness.
- Testing and Inspection: Ultrasonic testing (UT) for internal defects, tensile and impact testing per EN 10028-2; optional NDT for weld zones.
- Finishing: Edge trimming and surface shot blasting; optional pickling for scale removal to prepare for welding or coating.
4. Typical Application Fields
Pressure Vessels and Boilers
Shells, heads, and drums for steam boilers, hot water tanks, and chemical reactors operating up to 400°C and moderate pressures.
Piping and Fittings
Welded pipes, flanges, and valves for medium-pressure steam lines, heating systems, and industrial fluid transport.
Power Generation
Components in thermal power plants, including superheater tubes and economizers, compliant with PED 2014/68/EU directives.
General Industrial
Storage tanks, heat exchangers, and structural parts in petrochemical and manufacturing sectors requiring weldable, cost-effective steel.
5. Difference from Similar Grades (P265GH vs P295GH vs P355GH)
| Grade | Yield Strength (ReH) | Key Advantage | Suitable Scenario |
|---|---|---|---|
| P265GH | ≥ 265 MPa | Excellent weldability and moderate strength; cost-effective | Low to medium pressure vessels up to 400°C |
| P295GH | ≥ 295 MPa | Higher strength for thicker sections; better creep resistance | Medium-pressure boilers and higher load applications |
| P355GH | ≥ 355 MPa | Superior tensile properties; enhanced toughness | High-pressure equipment and elevated temperature service |
6. Selection & Usage Precautions
- Temperature Limits: Suitable for service up to 450°C; avoid prolonged exposure above 400°C to prevent graphitization and loss of strength — consider alloyed grades for higher temperatures.
- Welding Guidelines: Preheat to 150-200°C for thicknesses >20 mm; use low-hydrogen electrodes (e.g., E7018) and post-weld heat treatment if required to minimize cold cracking.
- Corrosion Protection: Susceptible to atmospheric corrosion; apply protective coatings or galvanizing for outdoor use; not recommended for highly corrosive environments without additional alloys.
- Quality Assurance: Verify compliance with EN 10028-2 via material certificates (EN 10204 3.1); perform hydrostatic testing for pressure vessel applications per ASME or PED standards.
7. Get a Carbon Steel Quote
If you need customized P265GH carbon steel products (plates, sheets, pipes) or want to get a detailed price quote for your pressure vessel projects, please contact our team directly. Our specialists will provide professional technical support and competitive pricing based on your requirements.