P265GH-TC2 Seamless Steel Pipe: High Temperature Pressure Vessel Tube
P265GH-TC2 is a non-alloy high-pressure seamless steel pipe manufactured in accordance with EN 10216-2. It is primarily designed for service under medium to high pressure at temperatures up to 450°C. Featuring stringent non-destructive testing standards and stable high-temperature mechanical properties, it serves as a key tubular product for boilers, pressure vessels, energy and chemical industries.
1. Grade Definition & Applicable Standards
1.1 Grade Interpretation
- P: Pressure vessel steel
- 265: Minimum yield strength of no less than 265 MPa at room temperature
- GH: Fine grain structure (G) and high-temperature resistance (H), ensuring excellent stability at elevated temperatures
- TC2: A testing grade specified by EN 10216-2 requiring 100% full-length inspection for longitudinal defects. Compared with TC1 which only tests pipe ends, TC2 delivers a higher level of operational safety.
1.2 Applicable Standards
Primary Standard: EN 10216-2 P265GH tube (Seamless steel tubes for pressure purposes — Part 2: Non-alloy and alloy steel tubes with specified elevated temperature properties)
Material Number: 1.0425 (European standard unified designation)
Quality Documentation: Products shall be delivered with EN 10204 3.1/3.2 inspection certificates to guarantee full traceability of chemical composition and mechanical properties.
2. Chemical Composition & Mechanical Properties
2.1 Chemical Composition (Cast Analysis, wt%)
| Element | C | Mn | S | P | Al |
|---|---|---|---|---|---|
| Specification | ≤0.20 | 0.80-1.40 | ≤0.015 | ≤0.025 | ≥0.020 |
The low carbon content ensures excellent weldability. Manganese improves material toughness and hardenability. Strict limitation on sulfur and phosphorus reduces the risk of intergranular corrosion. Aluminum refines grain structure and enhances high-temperature stability.
2.2 Main Mechanical Properties (Room Temperature, Wall Thickness ≤ 16 mm)
| Property | Value | Remarks |
|---|---|---|
| Tensile Strength (Rm) | 410-530 MPa | Suitable for medium and high pressure service |
| Yield Strength (ReH) | ≥265 MPa | Slightly decreased with increased wall thickness |
| Elongation (A) | ≥22% | Tested on 5x gauge length specimens, suitable for cold bending and expanding |
| Impact Energy (Akv) | ≥40 J | Tested at 20°C, ensuring good toughness |
2.3 High-Temperature Properties (200-450°C)
The yield strength is no less than 245 MPa at 200°C, with stable long-term rupture strength (≥60 MPa at 350°C for 10⁵ hours). No obvious high-temperature embrittlement occurs below 450°C, and its oxidation resistance fully meets the long-term service requirements of boiler superheaters and headers.
3. Production Process & Core Advantages of TC2
3.1 Full Production Process
- Billet Preparation: Low-sulfur and low-phosphorus continuous casting billets are adopted to ensure high material purity.
- Seamless Rolling: Adopt piercing and continuous rolling process with finishing rolling temperature above 850°C to achieve dense metallographic structure.
- Normalizing Treatment: Heated and held at 880-940°C, then cooled in still air for grain refinement, which improves the uniformity of mechanical properties by 30%.
- Finishing and Inspection: After straightening and dimensional calibration, pipes undergo dedicated TC2 non-destructive testing.
3.2 Key Differences between TC1 and TC2
TC1
Only longitudinal defect inspection on pipe ends, applied to low-pressure and non-critical components.
TC2 (Premium)
100% full-length ultrasonic testing for longitudinal defects. Cracks, laminations and other flaws are detected along the entire pipe length with no blind zones. Ideal for high-pressure and high-risk working conditions with superior safety margin.
4. Key Characteristics & Application Fields
4.1 Main Characteristics
- Excellent Weldability: Low carbon equivalent enables compatibility with submerged arc welding and manual metal arc welding. Low-hydrogen welding consumables are recommended. For thick-wall pipes under low ambient temperature, only local preheating is required, and post-weld heat treatment is not mandatory.
- Outstanding High-Temperature Stability: The fine grain structure provides good resistance to creep and thermal fatigue, with negligible performance degradation during long-term service below 450°C.
- Good Formability: High elongation allows cold bending, expanding, reducing and other forming processes for complex pipe fittings.
4.2 Major Applications
- Power Plant Boilers: Superheaters, reheaters, steam headers and main steam pipelines for supercritical and subcritical units conveying high-temperature steam.
- Pressure Vessels: Boiler drums, high-pressure storage tanks and heat exchanger shells, operating at pressure above 15 MPa.
- Petrochemical Industry: Piping for hydrogenation reactors, catalytic units and solvent recovery towers, with qualified resistance to hydrogen-induced cracking (HIC).
- Energy Equipment: Auxiliary piping for nuclear power plants, high-pressure gas storage tanks (20 MPa natural gas storage) and heating pipe networks.
5. Dimensions & Delivery Requirements
| Outside Diameter | 10.2 mm - 711 mm |
|---|---|
| Wall Thickness | 1.25 mm - 60 mm |
| Length | 1000 mm - 18000 mm (custom lengths available) |
| Delivery Condition | Normalized (+N). Surface finishes including anti-rust coating, blackening and polishing are optional. |
| Acceptance Inspection | Verify material certificates batch by batch, conduct random inspection on dimensions and mechanical properties, and review full-length TC2 non-destructive testing reports. |
6. Conclusion
With precise chemical composition control, reliable high-temperature performance and full-length non-destructive testing, P265GH-TC2 seamless steel pipe is a premium choice for medium and high pressure service at elevated temperatures. Compared with TC1 grade, its comprehensive inspection standard greatly reduces operational risks. Widely used in boilers, pressure vessels, energy and chemical sectors, it is a cost-effective and high-safety benchmark product among European standard pressure-bearing steel tubes.
EN 10204 3.1/3.2
Full traceability of chemical and mechanical properties with inspection certificates.
Normalized (+N)
Fine grain ensures uniformity and high temperature creep resistance.
TC2 100% NDT
Longitudinal defect inspection across entire length – zero blind zones, maximum safety.
* All technical data comply with EN 10216-2 : 2014 + A1:2019. Reliable for high-temperature and pressure applications up to 450°C.