superheaters seamless steel tube
Seamless carbon steel pipes for boilers and superheaters are critical piping materials used in high-temperature and high-pressure applications such as boilers and superheaters. These pipes exhibit characteristics including high-temperature resistance, creep resistance, and stable microstructure, with different standards and materials compatible with varying pressure and temperature grades. The following section elaborates on core standards, material properties, key performance characteristics, and application scenarios.
core standard system
table
Standard Number | applicable scene | Representative material | Key Requirements |
GB/T 3087-2022 | Low-and medium-pressure boilers (≤5.9 MPa, ≤450°C), such as superheated steam pipes and boiling water pipes | 10#,20# high-quality carbon steel | requires water pressure, flattening, and expansion tests, delivered in hot-rolled or normalized condition |
GB/T 5310-2017 | Boilers at high pressure and above (≥9.8MPa,≤580℃), such as superheaters and reheater tubes | 20G,20MnG, 25MnG, etc. | Strict control of sulfur-phosphorus content, requiring high-temperature tensile strength, long-term strength, grain size (≥4 grade), and 100% flaw detection |
ASTM A192/ASME SA192 | Seamless carbon steel pipe for high-pressure boilers, with an outer diameter of 12.7-177.8 mm and a wall thickness of 2.2-25.4 mm. | seamless carbon steel | Specify chemical components such as carbon and manganese, along with requirements for flattening, flaring, hardness, and hydraulic testing. |
ASTM A210/ASME SA210 | Medium carbon steel boilers and superheater tubes, such as A210GrA1 and A210GrC | medium carbon steel | High-temperature strength and good plasticity, suitable for water-cooled walls, superheaters, etc. |
Main Material Properties
- 20G (GB/T 5310-2017): Contains 0.17%-0.24% carbon, 0.35%-0.65% manganese, ≤0.30% silicon, and ≤0.025% sulfur-phosphorus. After normalizing treatment, it achieves a room temperature tensile strength of ≥410 MPa, yield strength of ≥245 MPa, and elongation of ≥24%. The material must also meet high-temperature yield strength requirements at 450°C, suitable for applications such as high-pressure superheaters and main steam pipes.
- 20# (GB/T 3087-2022): High-quality carbon structural steel with excellent plasticity, toughness, and weldability, suitable for use in low-and medium-pressure boiler heating surface tubes and steam pipelines.
- A210GrC (ASME SA210) features higher carbon and manganese content, delivering superior tensile and yield strength compared to A210GrA1. Its enhanced high-temperature resistance significantly extends the service life of superheater pipelines.
key performance requirements
- Mechanical properties: High-temperature tensile strength, yield strength, elongation, and creep strength must be ensured under high-pressure conditions. The 20G material must meet specific yield strength requirements at 450°C. Low-and medium-pressure materials must comply with room-temperature mechanical performance indicators.
- Process performance: All must pass hydraulic pressure, flattening, and expansion tests. High-pressure pipes must also undergo 100% non-destructive testing (ultrasonic or eddy current) to ensure defect-free.
- The high pressure tube should control the grain size and non-metallic inclusions to prevent the microstructure deterioration and creep failure during long-term service at high temperature.
Manufacturing and Application Points
- Manufacturing process: Typically employs hot rolling with piercing followed by continuous rolling or cold drawing. Cold drawing achieves superior dimensional accuracy (with outer diameter tolerance within ±0.1mm). High-pressure tubes require rigorous heat treatment (e.g., normalizing) to ensure microstructure and performance.
- Selection criteria: Select materials and standards based on boiler pressure and temperature. For high-pressure and high-temperature applications, 20G or A210GrC are recommended; for low and medium pressure applications, 20# or 10# is sufficient.
- Quality control: Focus on monitoring chemical composition, heat treatment, non-destructive testing, and mechanical testing to ensure compliance with relevant standards.
Comprehensive score