GB/T 5310 15MoG Seamless Steel Pipe for High-Pressure Boilers
15MoG Steel Tube: High-Temperature Boiler Pipe for Demanding Thermal Applications
Explore the properties, chemical composition, and applications of 15MoG seamless steel tube, a GB5310 standard material designed for high-pressure boiler and superheater systems. Ideal for elevated temperatures up to 530°C.
Hot-rolling, cold-drawing, normalizing, tempering, bending, welding (with suitable filler)
- Phone : +8618037372205
- Email : [email protected]
- WhatsApp: Contact via Whtsapp
- WeChat: +8618037372205
GB/T 5310 15MoG Seamless Steel Pipe for High-Pressure Boilers Introduction
15MoG is a low-carbon manganese-molybdenum alloy steel specified in GB 5310 for seamless steel tubes used in high-pressure boilers. It offers excellent heat resistance, good weldability, and adequate strength at elevated temperatures up to approximately 530°C. The addition of molybdenum enhances creep strength and resistance to graphitization. This steel is primarily employed in water-wall tubes, superheaters, reheaters, and steam pipelines within power generation and industrial boiler systems. Its fine-grained microstructure and controlled impurities ensure reliable performance under cyclic thermal loads and high internal pressures. The material is usually supplied in normalized or normalized and tempered condition, guaranteeing uniform mechanical properties and long-term service stability in corrosive flue gas environments.
GB/T 5310 15MoG Seamless Steel Pipe for High-Pressure Boilers Chemical Composition
The chemical composition of 15MoG steel is carefully controlled to achieve the required high-temperature strength and oxidation resistance. Molybdenum is the primary alloying element, improving creep strength and preventing temper embrittlement. Low sulfur and phosphorus contents ensure good ductility and weldability. Residual elements like chromium, nickel, and copper are tightly restricted.
| Element | Standard Value | Remarks |
|---|---|---|
| Carbon (C) | 0.12 – 0.20 | Core strength element |
| Silicon (Si) | 0.17 – 0.37 | Deoxidizer, improves oxidation resistance |
| Manganese (Mn) | 0.40 – 0.80 | Enhances hardenability and strength |
| Molybdenum (Mo) | 0.25 – 0.35 | Key element for creep resistance |
| Phosphorus (P) | ≤ 0.025 | Strict control for toughness |
| Sulfur (S) | ≤ 0.015 | Strict control for hot workability |
| Chromium (Cr) | ≤ 0.30 | Residual element |
| Nickel (Ni) | ≤ 0.30 | Residual element |
| Copper (Cu) | ≤ 0.20 | Residual element |
| Vanadium (V) | ≤ 0.08 | Residual element, may refine grain |
GB/T 5310 15MoG Seamless Steel Pipe for High-Pressure Boilers Thermal and Electrical Physical Properties
The physical properties of 15MoG are representative of low-alloy ferritic steels. Values are influenced by temperature and heat treatment condition. Thermal conductivity and expansion coefficients are critical for design under thermal cycling. Electrical resistivity is provided for completeness.
| Property | Standard Value | Unit | Test Condition / Temperature |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | Room temperature |
| Elastic Modulus (E) | 210 | GPa | Room temperature |
| Shear Modulus (G) | 81 | GPa | Room temperature |
| Poisson's Ratio (ν) | 0.3 | - | Room temperature |
| Thermal Expansion Coefficient (α) | 12.5 | 10⁻⁶/K | 20–300°C |
| Thermal Expansion Coefficient (α) | 13.1 | 10⁻⁶/K | 20–400°C |
| Thermal Expansion Coefficient (α) | 13.6 | 10⁻⁶/K | 20–500°C |
| Thermal Conductivity (λ) | 44 | W/(m·K) | 100°C |
| Thermal Conductivity (λ) | 40 | W/(m·K) | 300°C |
| Thermal Conductivity (λ) | 36 | W/(m·K) | 500°C |
| Specific Heat Capacity | 460 | J/(kg·K) | 20°C |
| Electrical Resistivity (ρ_e) | 0.23 | Ω·mm²/m | Room temperature |
GB/T 5310 15MoG Seamless Steel Pipe for High-Pressure Boilers Mechanical Properties
The mechanical properties of 15MoG tubes are tested at room temperature on longitudinal specimens. Minimum values depend on wall thickness. The steel exhibits a good combination of tensile strength and ductility, ensuring reliable forming and service performance. Impact testing is mandatory for wall thicknesses above a certain limit to guarantee toughness.
| Property | Standard Requirement | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) | ≥ 270 (wall thickness ≤ 16 mm) | MPa | Room temperature, longitudinal |
| Yield Strength (ReH) | ≥ 260 (wall thickness 16–40 mm) | MPa | Room temperature, longitudinal |
| Tensile Strength (Rm) | 450 – 600 | MPa | Room temperature, longitudinal |
| Elongation (A) | ≥ 22 (longitudinal) | % | Gauge length 5.65√S0 |
| Elongation (A) | ≥ 20 (transverse) | % | Transverse, when applicable |
| Impact Energy (KV2) | ≥ 40 | J | 0°C, longitudinal, for wall thickness ≥12 mm |
| Bend Test (bend angle 180°) | No cracks (d=3a) | - | Room temperature, for OD ≤ 60 mm |
GB/T 5310 15MoG Seamless Steel Pipe for High-Pressure Boilers Completely Equivalent Material Standards and Replaceable Grades
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| China | GB 5310 | 15MoG | Original standard; primary selection |
| No internationally identical grade | - | - | Closest matches are similar, not fully identical due to minor composition differences |
GB/T 5310 15MoG Seamless Steel Pipe for High-Pressure Boilers Application Introduction
15MoG is specifically engineered for high-pressure, high-temperature boiler components. Its balanced composition ensures long-term microstructural stability under stress and temperature. This material is suitable for forming, bending, and welding with appropriate preheating and post-weld heat treatment. It is not recommended for applications where the metal temperature exceeds 530°C for extended periods, as graphitization may occur. Alternative grades like 12Cr1MoVG or T22 should be considered for higher temperatures.
Product Applications: High-pressure boiler water-wall panels, Superheater and reheater tube bundles, Main steam piping and headers, Desuperheater shells and connecting pipes, Pressure parts in nuclear secondary loop (non-irradiated)
Processed into products: Boiler tubes (straight and U-bent), Elbow and tee fittings, Reducer and cap sections, Collector and manifold stub welds, Thermal expansion loops
Application industries: Power generation (coal-fired, gas-fired, biomass boilers), Industrial boiler manufacturing, Combined heat and power (CHP) plants, Petrochemical and refinery process heaters, Heat recovery steam generators (HRSG)
GB/T 5310 15MoG Seamless Steel Pipe for High-Pressure Boilers Similar / Alternative Material Recommendations
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| USA / International | ASTM A209 / ASME SA-209 | Grade T1 (K11522) | Similar C-Mo steel; Mo 0.44-0.65%, slightly higher strength; used for boiler tubes up to 530°C |
| EU | EN 10216-2 | 16Mo3 (1.5415) | Most commonly used European C-Mo steel; Mo 0.25-0.35%, very close to 15MoG; widely interchangeable |
| Japan | JIS G3461 | STBA12 | Molybdenum steel tube for boiler and heat exchanger; similar application range |
| Germany (historical) | DIN 17175 | 15Mo3 | Predecessor to EN 16Mo3; seamless tubes for high-temperature service, now superseded |
Notes:
Welding: 15MoG can be welded by GTAW, SMAW, SAW processes. Preheating to 150–200°C is recommended, and PWHT at 620–680°C is typically applied to relieve stress.
Inspection: Hydrostatic test, eddy current test, ultrasonic test, and dimensional checks are performed according to GB 5310. Surface quality must be free from cracks, laps, and injurious defects.
Maximum service temperature: 15MoG is generally suitable for metal temperatures up to 530°C. Above this, oxidation and graphitization risks increase. For higher temperatures, chromium-molybdenum steels (e.g., 12Cr1MoVG, T/P22) should be considered.
- Share
