ASTM A213 T91 Seamless Tube | ASME SA213 T91 Alloy Steel Boiler Tubes
ASTM A213 / ASME SA213 T91 Seamless Alloy Steel Tubes
ASTM A213 T91 seamless tubes, also known as ASME SA213 T91 boiler tubes, are high-performance ferritic alloy steel tubes designed for high-temperature and high-pressure service.
Grade T91 (9Cr-1Mo-V-Nb alloy steel) contains approximately 9% chromium and 1% molybdenum, micro-alloyed with vanadium and niobium. This composition significantly improves:
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High-temperature creep strength
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Oxidation resistance in steam environments
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Long-term microstructural stability
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Resistance to thermal fatigue
Because of these properties, T91 seamless alloy steel tubes are widely used in supercritical power plants, HRSG boiler tube, petrochemical plants, and high-temperature heat exchangers.
What Is ASTM A213 / ASME SA213?
ASTM A213 (ASME SA213) is the standard specification covering seamless ferritic and austenitic alloy steel tubes for high-temperature service.
These tubes are mainly used in:
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Boilers
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Superheaters
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Reheaters
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Heat exchangers
The specification defines requirements for:
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Chemical composition
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Mechanical properties
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Heat treatment
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Manufacturing methods
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Inspection and certification
ASTM A213 tubes are widely used in ASME Boiler and Pressure Vessel Code (BPVC) applications.
Download ASTM A213 standard pdf
Material Grade – T91 (9Cr-1Mo-V-Nb Alloy Steel)
T91 alloy steel is a modified 9Cr-1Mo martensitic steel developed to replace older grades such as T11 and T22.
Key advantages include:
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Higher creep rupture strength
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Improved oxidation resistance in steam
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Better long-term stability at elevated temperatures
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Increased thermal efficiency for power plants
These properties make ASTM A213 T91 boiler tubes ideal for supercritical and ultra-supercritical power generation systems.
ASTM A213 T91 Tube Specifications
Product Type
Seamless ferritic alloy steel tube
Manufacturing Process
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Hot finished
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Cold drawn
Delivery Condition
Normalized and Tempered (N&T)
Size Range
Outside Diameter
12.7 mm – 114.3 mm (1/2″ – 4-1/2″)
Wall Thickness
2.0 mm – 14.0 mm
Length
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Random length
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Fixed length
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Custom lengths available
Chemical Composition of ASTM A213 T91
| Element | Content (%) |
|---|---|
| C | 0.07 – 0.14 |
| Mn | 0.30 – 0.60 |
| Si | 0.20 – 0.50 |
| Cr | 8.0 – 9.5 |
| Mo | 0.85 – 1.05 |
| Nb | 0.06 – 0.10 |
| Ni | ≤0.40 |
| P | ≤0.020 |
| S | ≤0.010 |
The combination of Cr-Mo-V-Nb alloying elements provides excellent resistance to creep deformation and steam oxidation.
Mechanical Properties of T91 Boiler Tubes
| Property | Value |
|---|---|
| Tensile Strength | ≥585 MPa |
| Yield Strength | ≥415 MPa |
| Elongation | ≥20% |
| Hardness | 190 – 250 HB |
These mechanical properties allow T91 alloy steel tubes to withstand high-pressure steam environments.
Heat Treatment Requirements
ASTM A213 T91 tubes must be supplied in normalized and tempered condition.
Typical heat treatment parameters:
| Process | Temperature |
|---|---|
| Austenitizing | 1040 – 1080°C |
| Cooling | Air Cooling |
| Tempering | 730 – 800°C |
After welding, post-weld heat treatment (PWHT) is required to maintain mechanical integrity.
Inspection and Testing
All ASME SA213 T91 seamless tubes undergo strict inspection including:
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Chemical composition analysis
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Tensile testing
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Hardness testing
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Flattening and bend tests
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Eddy current testing
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Hydrostatic pressure testing
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Dimensional inspection
Certification available:
EN 10204 3.1 Mill Test Certificate
T91 vs T22 vs T92 Boiler Tubes
| Grade | Alloy System | Max Temperature | Typical Application |
|---|---|---|---|
| T22 | 2.25Cr-1Mo | ~580°C | Conventional boilers |
| T91 | 9Cr-1Mo-V | ~610-620°C | Supercritical boilers |
| T92 | 9Cr-0.5Mo-W | ~650°C | Ultra-supercritical plants |
Compared with T22, T91 offers higher creep strength and longer service life in high-temperature steam systems.
Applications of ASTM A213 T91 Tubes
Power Plants
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Superheater tubes
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Reheater tubes
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High-pressure steam pipelines
HRSG Systems
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Heat recovery steam generators
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Gas turbine exhaust heat exchangers
Petrochemical Industry
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Refinery heaters
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High-temperature process piping
Industrial Heat Systems
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Heat exchangers
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Pressure vessels
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High-temperature piping systems
Advantages of T91 Alloy Steel Tubes
✔ Excellent creep rupture strength
✔ Superior steam oxidation resistance
✔ Long service life in high-temperature boilers
✔ Improved thermal efficiency for power plants
✔ Reduced maintenance costs
FAQ – ASTM A213 T91 Boiler Tubes
What is ASTM A213 T91 tube?
ASTM A213 T91 is a 9Cr-1Mo-V alloy steel tube designed for high-temperature and high-pressure boiler applications.
What is the maximum service temperature for T91?
T91 tubes can typically operate at 610–620°C, making them suitable for supercritical power plants.
What is the difference between T22 and T91?
T91 provides much higher creep strength and temperature capability than T22, allowing more efficient power generation.
Is post-weld heat treatment required for T91?
Yes. PWHT is mandatory after welding to prevent cracking and restore mechanical properties.
ASTM A213 T91 Boiler Tube Supplier
We are a professional manufacturer and exporter of ASTM A213 / ASME SA213 T91 seamless alloy steel boiler tubes.
Our products feature:
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Strict quality inspection
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Competitive factory prices
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Custom manufacturing
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Global export packaging
All tubes are supplied with EN 10204 3.1 certification and full traceability.
ASTM A213 ASME SA213 T91 seamless tube
ASTM A213 / ASME SA213 T91 seamless ferritic alloy-steel boiler tubes provide superior creep strength, oxidation resistance, and long-term reliability for high-temperature and high-pressure boiler applications. Fully compliant with ASTM and ASME standards, T91 tubes are the preferred solution for modern power plants and advanced thermal systems.
For technical datasheets, pricing, and project support, contact us freely.
Download ASTM A213 / ASME SA213 T91 seamless tube specificaiton
