GB/T 5310 Seamless Steel Tubes and Pipes
For High Pressure Boiler – Current Standard: GB/T 5310-2023
Grades 20G, 25MnG, 15MoG, 15CrMoG, 12Cr2MoG, 12Cr1MoVG
Hot rolled, Cold drawn, or Hot expanded – Heat treated condition
Product Overview
GB/T 5310 is the Chinese national standard for seamless steel tubes and pipes used in the manufacture of high pressure boilers and high temperature pressure equipment. These tubes are specifically designed for service where temperatures reach 450°C to 650°C and working pressures exceed 9.8 MPa.
Key applications include:
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Superheater tubes
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Reheater tubes
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Economizer tubes
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Water wall tubes
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Boiler headers and steam pipelines
Standard Update – Important:
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Previous standard: GB/T 5310-2017 (effective 2018-09-01, expired 2024-04-01)
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Current standard: GB/T 5310-2023 (effective 2024-04-01)
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Key change: Hot expansion process now fully recognized in the seamless tube manufacturing system
Available Grades:
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Carbon steel: 20G (most popular), 25MnG
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Molybdenum alloy: 15MoG
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Chrome-molybdenum alloy: 15CrMoG, 12Cr2MoG, 12Cr1MoVG
✅ GB/T 5310-2023 compliant – Current standard (effective April 1, 2024)
✅ High pressure capability – Working pressure >9.8 MPa
✅ High temperature service – Up to 650°C
✅ Seamless construction – Pressure integrity assured
✅ Multiple manufacturing methods – Hot rolled, cold drawn, or hot expanded
✅ Heat treated – Normalized, normalized + tempered, or quenched + tempered
✅ 100% hydrostatic tested – Guaranteed pressure integrity
✅ EN 10204 Type 3.1 MTC provided with full traceability
✅ Factory direct | Global shipping
Key Specifications
| Parameter | Details |
|---|---|
| Standard | GB/T 5310-2023 (supersedes GB/T 5310-2017) |
| Product Type | Seamless Steel Tube and Pipe for High Pressure Boiler |
| Steel Grades | 20G, 25MnG, 15MoG, 15CrMoG, 12Cr2MoG, 12Cr1MoVG |
| Manufacturing Methods | Hot rolled, Cold drawn (rolled), Hot expanded |
| OD Range (Hot rolled) | 22mm – 530mm |
| OD Range (Cold drawn) | 10mm – 108mm |
| OD Range (Hot expanded) | Up to 820mm (by agreement) |
| Wall Thickness (Hot rolled) | 2.0mm – 70mm |
| Wall Thickness (Cold drawn) | 2.0mm – 13.0mm |
| Length | 4m – 12m (fixed or random) |
| Delivery Condition | Normalized, normalized + tempered, quenched + tempered |
| Surface Finish | Black / Bare / Oiled |
| End Finish | Plain / Beveled |
Steel Grade Overview
| Grade | Type | Max Temp (°C) | Yield Strength (MPa) | Tensile (MPa) | Typical Application |
|---|---|---|---|---|---|
| 20G | Carbon steel | 450 | ≥245 | 410-550 | Economizer, water wall, low temp superheater |
| 25MnG | Carbon steel (Mn) | 450 | ≥240 | ≥415 | Higher strength carbon boiler tubes |
| 15MoG | Mo-alloy | 500 | ≥270 | 450-600 | Medium temperature service |
| 15CrMoG | 1Cr-0.5Mo | 550 | ≥235 | 440-640 | High temperature superheater |
| 12Cr2MoG | 2.25Cr-1Mo | 550 | ≥280 | 450-600 | High pressure, high temperature |
| 12Cr1MoVG | 1Cr-1Mo-V | 580 | ≥255 | 470-640 | Advanced high temperature |
💡 20G is the most popular grade – widely used for general high pressure boiler service.
Chemical Composition – GB/T 5310 Grades
| Grade | C (%) | Mn (%) | Si (%) | Cr (%) | Mo (%) | V (%) | P,S max |
|---|---|---|---|---|---|---|---|
| 20G | 0.17-0.24 | 0.35-0.65 | 0.17-0.37 | — | — | — | 0.030 |
| 25MnG | 0.22-0.30 | 0.70-1.00 | 0.17-0.37 | — | — | — | 0.030 |
| 15MoG | 0.12-0.20 | 0.40-0.80 | 0.17-0.37 | — | 0.25-0.35 | — | 0.030 |
| 15CrMoG | 0.12-0.18 | 0.40-0.70 | 0.17-0.37 | 0.80-1.10 | 0.40-0.55 | — | 0.030 |
| 12Cr2MoG | 0.08-0.15 | 0.40-0.70 | ≤0.50 | 2.00-2.50 | 0.90-1.20 | — | 0.030 |
| 12Cr1MoVG | 0.08-0.15 | 0.40-0.70 | 0.17-0.37 | 0.90-1.20 | 0.25-0.35 | 0.15-0.30 | 0.030 |
💡 Low phosphorus and sulfur (≤0.030%) ensures excellent toughness and weldability.
Mechanical Properties – GB/T 5310 Grades
| Grade | Tensile Strength (MPa) | Yield Strength (MPa) min | Elongation (%) min |
|---|---|---|---|
| 20G | 410 – 550 | ≥245 | ≥24 |
| 25MnG | ≥415 | ≥240 | ≥22 |
| 15MoG | 450 – 600 | ≥270 | ≥22 |
| 15CrMoG | 440 – 640 | ≥235 | ≥21 |
| 12Cr2MoG | 450 – 600 | ≥280 | ≥20 |
| 12Cr1MoVG | 470 – 640 | ≥255 | ≥21 |
💡 20G offers excellent balance of strength (≥245 MPa yield) and ductility (≥24% elongation) – the workhorse grade for high pressure boilers.
Grade Selection Guide – High Pressure Boiler Application
| Boiler Section | Operating Temp | Recommended Grade | Key Property |
|---|---|---|---|
| Economizer | ≤400°C | 20G | Corrosion resistance |
| Water Wall | ≤400°C | 20G | Thermal fatigue resistance |
| Low Temp Superheater | ≤450°C | 20G | Creep strength |
| Medium Temp Superheater | 450-500°C | 15MoG | Mo-alloy creep resistance |
| High Temp Superheater | 500-550°C | 15CrMoG | Cr-Mo oxidation resistance |
| Reheater | 550-580°C | 12Cr1MoVG | V-alloy high temp strength |
| High Pressure Header | ≤550°C | 12Cr2MoG | Heavy wall capability |
💡 20G is suitable for temperatures up to 450°C. For service above 450°C, alloy grades (15CrMoG, 12Cr1MoVG) must be used .
Manufacturing Methods – GB/T 5310-2023
| Method | Description | OD Range | Typical Applications |
|---|---|---|---|
| Hot rolled | Rolled at high temperature | 22-530mm | Standard boiler tubes |
| Cold drawn (rolled) | Cold worked for precision | 10-108mm | Small diameter, precision tubes |
| Hot expanded | Expanded by heating | Up to 820mm | Large diameter boiler components |
💡 The 2023 standard officially recognizes hot expansion as a seamless tube manufacturing method.
Available Sizes – GB/T 5310 Boiler Tubes
Hot Rolled Tubes:
| OD (mm) | WT Range (mm) | Typical Grade | Application |
|---|---|---|---|
| 22 – 60 | 2.0 – 8.0 | 20G | Small boiler tubes |
| 60 – 114 | 3.0 – 12.0 | 20G, 15CrMoG | General boiler |
| 114 – 219 | 5.0 – 20.0 | 20G, 12Cr1MoVG | Main steam – most common |
| 219 – 325 | 6.0 – 30.0 | 12Cr1MoVG, 12Cr2MoG | Headers, large tubes |
| 325 – 426 | 8.0 – 40.0 | 12Cr2MoG | Superlarge headers |
| 426 – 530 | 10.0 – 70.0 | By agreement | Special applications |
Cold Drawn (Rolled) Tubes:
| OD (mm) | WT Range (mm) | Typical Grade | Application |
|---|---|---|---|
| 10 – 25 | 1.5 – 4.0 | 20G | Small diameter |
| 25 – 50 | 2.0 – 6.0 | 20G, 15CrMoG | Precision tubes |
| 50 – 76 | 2.5 – 10.0 | 15CrMoG | Superheater elements |
| 76 – 108 | 3.0 – 13.0 | 12Cr1MoVG | High strength small bore |
💡 Most popular size: 114.3mm to 219.1mm OD for main steam lines and headers.
Quality Assurance & Testing
| Test | Method | Coverage | Requirement |
|---|---|---|---|
| Hydrostatic Test | Water pressure | 100% | Mandatory |
| Ultrasonic Testing (UT) | Non-destructive | By agreement | Optional |
| Eddy Current (ET) | Non-destructive | By agreement | Optional |
| Tensile Test | EN ISO 6892-1 | Per lot | All grades |
| High Temperature Creep Test | GB/T standard | Per lot | For alloy grades |
| Flattening Test | Ductility | Per lot | All grades |
| Flaring Test | Tube end expansion | Per lot | All grades |
| Microstructure Examination | Metallographic | Per lot | Grain size, decarburization |
| Dimensional Inspection | Micrometer | 100% | All grades |
💡 100% hydrostatic testing is mandatory for all high pressure boiler tubes.
Heat Treatment Requirements
| Grade | Required Heat Treatment | Purpose |
|---|---|---|
| 20G, 25MnG | Normalized | Uniform grain structure, good strength |
| 15MoG, 15CrMoG | Normalized + Tempered | Improved toughness |
| 12Cr2MoG | Normalized + Tempered | High temperature strength |
| 12Cr1MoVG | Normalized + Tempered | Creep resistance at high temp |
💡 Microstructure and grain size requirements are specified – fine grain structure (≥5) is required for all grades.
Applications – High Pressure Boiler Tubes
| Industry | Application | Recommended Grade | Service Temp/Pressure |
|---|---|---|---|
| Power Generation | Superheater tubes | 15CrMoG, 12Cr1MoVG | 450-580°C |
| Power Generation | Reheater tubes | 15CrMoG, 12Cr1MoVG | 450-580°C |
| Power Generation | Economizer tubes | 20G | ≤400°C |
| Power Generation | Water wall tubes | 20G | ≤400°C |
| Power Generation | Boiler headers | 12Cr2MoG, 12Cr1MoVG | High pressure |
| Industrial Boilers | Steam boiler tubes | 20G | 450°C |
| HRSG | Heat recovery tubes | 15CrMoG | 500°C |
| Petrochemical | High temp transfer lines | 12Cr1MoVG | Up to 580°C |
💡 Working conditions: Temperature 450-650°C, pressure >9.8 MPa.
Why Choose Our GB/T 5310 High Pressure Boiler Tubes?
| Advantage | Description |
|---|---|
| Current standard | GB/T 5310-2023 – fully compliant with latest requirements |
| Full grade range | 20G to 12Cr1MoVG – one-stop sourcing |
| 20G in stock | Most popular grade – ready to ship |
| Multiple manufacturing methods | Hot rolled, cold drawn, hot expanded – all recognized |
| 100% hydrostatic tested | Mandatory per standard – guaranteed integrity |
| Heat treated | Normalized or normalized + tempered – proper microstructure |
| High temperature performance | Creep strength data available for alloy grades |
| Full traceability | EN 10204 3.1 MTC with heat number |
| Global export | Shipped to power plants and boiler manufacturers worldwide |
Contact for Quote
Please provide the following details:
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Grade : 20G / 25MnG / 15MoG / 15CrMoG / 12Cr2MoG / 12Cr1MoVG
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OD (mm) : _______
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WT (mm) : _______
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Length (m) : _______
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Quantity : _______ (pieces / meters / tons)
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Manufacturing : Hot rolled / Cold drawn / Hot expanded
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Application : Superheater / Reheater / Economizer / Water wall / Header
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Service Temperature : _______ °C
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Inspection : Standard / Third-party (SGS/BV/TUV)
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Tags: GB/T 5310 High Pressure Boiler Tube 20G Boiler Tube 15CrMoG 12Cr1MoVG Seamless Boiler Tube Chinese Standard Power Plant Tube Superheater Tube
